RMZ MATERIALS AND GEOENVIRONMENT MATERIALI IN GEOOKOLJE Volume Letnik Ljubljana, November 2006 No. Št. RMZ - Materials and Geoenvironment RMZ - Materiali in geookolje Old title: Rudarsko-metalurški zbornik (Mining and Metallurgy Quarterly), ISSN 0035-9645, 1952-1997. Is issued quarterly by the Faculty of Natural Science and Engineering, Ljubljana, the Institute for Mining, Geotechnology and Environment Ljubljana and Premogovnik Velenje, Velenje. Izdaja Naravoslovnotehniška fakulteta Univerze v Ljubljani, Inštitut za rudarstvo, geotehnologijo in okolje Ljubljana in Premogovnik Velenje, štirikrat letno. Financially supported also by Ministry of Education, Science and Sport of Republic of Slovenia. Pri financiranju revije sodeluje Ministrstvo za šolstvo, znanost in šport Republike Slovenije. Editor-in-Chief (Glavni urednik) Jože Pezdič Editorial Management Jakob Likar Advisory Board Uredniški odbor Evgen Dervarič, Premogovnik Velenje Tadej Dolenec, Univerza v Ljubljani Stevo Dozet, GeoZS, Ljubljana Jadran Faganeli, Univerza v Ljubljani Vasilij Gontarev, Univerza v Ljubljani Mariusz Orion Jedrysek, University of Wroclaw František Kavička, Technical University of Brno Klaus Koch, Technische Universität Clausthal Tomaž Kolenko, Univerza v Ljubljani Jakob Lamut, Univerza v Ljubljani Jakob Likar, Univerza v Ljubljani David John Lowe, British Geological Survey Jernej Pavšič, Univerza v Ljubljani Andrej Paulin, Univerza v Ljubljani Jože Pezdič, Univerza v Ljubljani Simon Pire, Univerza v Ljubljani Esad Prohić, Sveučilište, Zagreb Anton Smolej, Univerza v Ljubljani Janez Stražišar, Univerza v Ljubljani Andrej Šubelj, ERGO Ljubljana France Šušteršič, Univerza v Ljubljani Rado Turk, Univerza v Ljubljani Milivoj Vulić, Univerza v Ljubljani Editorial Office (Uredništvo): Barbara Bohar Bobnar Iztok Anželj Nives Vukič Digital Layout (Priprava za tisk): Tomaž Sterniša s.p., Ljubljana Print (Tisk): R-TISK d.o.o, Ljubljana RMZ - Materials and Geoenvironment Aškerčeva cesta 12, p.p. 312 1001 Ljubljana, R. 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Ljubljana: UJP 01100-6030708186 Davčna številka: 24405388 ISSN 1408-7073 RMZ - MATERIALS AND GEOENVIRONMENT PERIODICAL FOR MINING, METALLURGY AND GEOLOGY RMZ - MATERIALI IN GEOOKOLJE REVIJA ZA RUDARSTVO, METALURGIJO IN GEOLOGIJO RMZ-M&G, Vol. 53, No. 3 pp. 285-417 (2006) Ljubljana, November 2006 Historical Review More than 80 years have passed since in 1919 the University Ljubljana in Slovenia was founded. Technical fields were joint in the School of Engineering that included the Geologic and Mining Division while the Metallurgy Division was established in 1939 only. Today the Departments of Geology, Mining and Geotechnology, Materials and Metallurgy are part of the Faculty of Natural Sciences and Engineering, University of Ljubljana. Before War II the members of the Mining Section together with the Association ofYugoslav Mining and Metallurgy Engineers began to publish the summaries of their research and studies in their technical periodical Rudarski zbornik (Mining Proceedings). Three volumes of Rudarski zbornik (1937, 1938 and 1939) were published. The War interrupted the publication and not untill 1952 the first number of the new journal Rudarsko-metalurški zbornik - RMZ (Mining and Metallurgy Quarterly) has been published by the Division of Mining and Metallurgy, University of Ljubljana. Later the journal has been regularly published quarterly by the Departments of Geology, Mining and Geotechnology, Materials and Metallurgy, and the Institute for Mining, Geotechnology and Environment. On the meeting of the Advisory and the Editorial Board on May 22nd 1998 Rudarsko-metalurški zbornik has been renamed into "RMZ - Materials and Geoenvironment (RMZ - Materiali in Geookolje)" or shortly RMZ - M&G. RMZ - M&G is managed by an international advisory and editorial board and is exchanged with other world-known periodicals. All the papers are reviewed by the corresponding professionals and experts. RMZ - M&G is the only scientific and professional periodical in Slovenia, which is published in the same form nearly 50 years. It incorporates the scientific and professional topics in geology, mining, and geotechnology, in materials and in metallurgy. The wide range of topics inside the geosciences are wellcome to be published in the RMZ - Materials and Geoenvironment. Research results in geology, hydrogeology, mining, geotechnology, materials, metallurgy, natural and antropogenic pollution of environment, biogeochemistry are proposed fields of work which the journal will handle. RMZ - M&G is co-issued and co-financed by the Faculty of Natural Sciences and Engineering Ljubljana, and the Institute for Mining, Geotechnology and Environment Ljubljana. In addition it is financially suported also by the Ministry of Education Science and Sport of Slovenian Government. Editor in chief Table of Contents - Kazalo Time - Dependent Processes in Rocks Časovno odvisni procesi v kamninah Likar, J., Vesel, G., Dervarič, E., Jeromel, G..............................................................................285 Možnost izvedbe visokotlačnega podzemnega skladišča zemeljskega plina na območju Rudnika Senovo High Pressure Storage of Gas in Area of Coal Mine Senovo VuKELIć, Ž., StERNAD, Ž., VuKADIN, v., ČADEŽ, F., HuDEJ, M., Pečovnik, i................................... 303 Assessment of surface deformation with simultaneous adjustment with several epochs of leveling networks by using nD relative pedaloid Ocena deformacij-s simultano izravnavo več terminskih izmer z nD relativnim daloidom Vulić, M., Vehovec, a..................................................................................................................315 Maximum Entropy Theory by Using the Meandering Morphological Investigation Yilmaz, L.......................................................................................................................................323 Structural maps of seismic horizons in the Krško basin Strukturne karte seizmičnih horizontov v Krški kotlini Gosar, A., Božiček, B....................................................................................................................339 Uporaba petrofizikalnih preiskav pri oceni obstojnosti in stopnji preperevanja naravnega kamna Use of petrophysical analysis for durability assessment and weathering degree of natural stone Kramar, s., Mirtič, B....................................................................................................................353 Ladinijske plasti na območju Oble Gorice, osrednja Slovenija Ladinian Beds in the Obla Gorica Area, Central Slovenia DozET, S.........................................................................................................................................367 Effect of the grain refinement, modification and the cooling rate on microstructure of the AlSi10Mg alloy Vpliv udrobnevanja, modificiranja in ohlajevalne hitrosti na mikrostrukturo zlitine AlSi10Mg Petric, M., Medved, J., Mrvar, P..................................................................................................385 Temperature field analysis of tunnel kiln for brick production Duraković, J., Delalić, S..............................................................................................................403 Autor's Index, Vol. 53, No. 3 ........................................................................................409 Instructions to Authors.................................................................................................410 Template.........................................................................................................................412 Number of paper indexing in diferent bases...............................................................417 Število indeksiranih člankov v posameznih bazah Time - Dependent Processes in Rocks V Časovno odvisni procesi v kamninah Jakob Likar1, Gregor Vesel1, Evgen Dervarič2, Gregor Jeromel2 1Faculty of Natural Sciences and Engineering , University of Ljubljana, Aškerčeva 12, 1000 Ljubljana, Slovenia; E-mail: jakob.likar@ntf.uni-lj.si, gregor.vesel@ntf.uni-lj.si 2Velenje Lignite Mines, Partizanska 78, 3320 Velenje, Slovenia: E-mail: evgen.dervaric@rlv.si, gregor.jeromel@rlv.si Received: November 02, 2006 Accepted: November 14, 2006 Abstract: Time-dependent transformations in rocks, which occur primarily as a consequence of their natural properties, are a significant factor in the analysis of deformations developing during the construction of underground structures and afterwards. The excavation method used and the method of supporting an underground structure depend to a considerable degree on the intensity of the time development of deformations and their size. The contribution analyzes the basic rheological models used for computational analyses of time-dependent displacements in the linings of underground structures using the so-called friendly cross sections, and provides a comparison between the measured and calculated displacement values. The exposure of a complex rock structure, which is a frequent occurrence in the construction of underground structures such as, for example, tunnels, is explained using back analyses. These are significant both from the perspective of proper selection of construction technology, and in cases when it is necessary to decide on the basic orientations to be used in the method of supporting a specific underground facility. Izvleček: Časovno odvisne spremembe v kamninah, ki so posledica predvsem njihovih naravnih lastnosti, so pomemben dejavnik pri analizi deformacij, ki se razvijejo v času gradnje podzemnega prostora in po njej. Od intenzivnosti časovnega poteka razvoja deformacij in njihovih velikosti, je v veliki meri odvisen način izkopa in podpiranja podzemnega prostora. V prispevku so analizirani osnovni reološki modeli, ki se uporabljajo za računske analize časovno odvisnih pomikov ostenj podzemnih prostorov s t.i. prijaznimi prečnimi profili in narejena primerjava med izmerjenimi in izračunanimi vrednostmi pomikov. Izpostavljenost kompleksne hribinske zgradbe, ki je pogosto primer pri gradnji podzemnih prostorov, kot npr. predorov, je pojasnjena s povratnimi analizami. Te so pomembne tako v pogledu pravilne izbire tehnologije gradnje, kakor tudi takrat, ko se je potrebno odločiti o osnovnih usmeritvah načina podpiranja določenega podzemnega objekta. Key words: rheological models, time-dependent deformations, viscoelasticity, Permian-Carboniferous rocks Ključne besede: reološki modeli, časovno odvisne deformacije, viskoelestičnost, permokar-bonske kamnine Introduction As is often the case in rock mechanics, a question that frequently arises with rheologi-cal models is how far we can go in applying various theories, developed on the basis of the elasticity or elastoplasticity theory, for the evaluation of actual occurrences in complex natural materials. Deformation occurrences in nature, including rocks, are often considerably more complicated than we can actually describe. That is why any progress towards such occurrences is encouraging and will pave the way for the scientific explanation of such processes. A knowledge of time-dependent processes in rocks is highly significant from the engineering aspect. In our case, we have in mind those processes involving the time development of stress changes and deformations in the vicinity of underground structures. These processes, which are of long duration and may last for several days or even decades, affect the transformation and redistribution of stresses in the vicinity ofthe underground structures. One of the consequences of this is an increased load on the supporting system and the reduced stability of the structure, which in extreme cases may even lead to collapse. Analyzing time-dependent processes in rocks and preparing evaluations of possible effects on the stability of an underground structure are of extreme importance in planning the construction schedule, selecting the appropriate supporting method, and ensuring the long-term stability of the structure. To determine or describe these processes, we frequently make use of various rheological models that are linked to individual parameters which can be determined on the basis of various procedures. These parameters may be determined in laboratories or with the help of back analyses, which is shown in this contribution. This paper is divided into an introductory theoretical part presenting basic information on time-dependent processes in rocks, and a practical part in which back analyses are used to determine the parameters of a simple linear, viscoelastic rheological model, which may be used to describe the time development of deformations while taking into account specific assumptions. Rheological Characteristics of rocks When calculating deformations in rocks in the vicinity of underground structures, equations are often used in which time does not appear as a variable and we have to content ourselves with so-called final deformations. Such cases are quite frequent and this method of calculating deformations may be completely satisfactory for the needs of standard dimensioning. However, one should be aware that no phenomena in nature is only of a momentary character, and that time is a parameter which can to a great degree influence the final result in rheologically sensitive rocks. In equations uniting the stresses and deformations of a deformable body, the introduction of an independent time variable leads to complicated mutual relations resulting in quite unfriendly mathematical solutions. Yet this method provides us with more detailed insight into the time development of deformations, which is of great significance in the construction of underground facilities with long-term use. There are some known cases in which insufficient attention was devoted to the investigation of such phenomena, neither in the period of designing a specific structure, nor during the course of its construction. The long-term effects of such actions appeared even after ten or more years. The consequences of these influences were numerous rehabilitation works on facilities, in some cases even demolitions. Today, the systematic investigation of time-dependent phenomena in rocks using numerical procedures and analyses enables better comparative analyses, particularly as regards considering no homogenity and anisotropy, which are frequently present in rocks. The rheology of rocks deals primarily with the following sub areas, which are thematically and conceptually oriented towards: • searching for and analyzing the causes of the occurrence of time-dependent processes, • the development and testing of rheolog-ical models and influential parameters for describing such processes, • the method of determining influential parameters, • searching for mathematical combinations presenting time-dependent processes, etc. Causes of time changes in stress and deformations The stresses and deformations occurring in the vicinity of underground facilities may change over time for various reasons. The most frequent among these are changes in loads or rock pressures occurring in and affecting rocks. Such cases occur, e.g. due to flowing strata waters (abundant precipitation, drainage), changes in the geometry of an excavated area (excavation round or gradual, phase construction of a specific type of facility), changes in size and additional loads on an area (construction of new structure in the immediate vicinity), changes in the deformation properties of rocks (weathering), and similar. A specific example of time-dependent changes in rock stresses and deformations is represented by the viscose properties of rocks. The viscose behavior of rocks causes the material to gradually deform under constant load, depending on the time period, which may last several decades. This phenomenon is also known as creep, whose causes may be explained by two principal factors, i.e. rock mass yielding and the formation of cracks. Some rocks, such as rock salt, tar sands, compact shales, etc. creep at relatively small deviatory stresses, despite their uncracked or undamaged, intact base. In the case of rock salt, the creep process includes movement of dislocations and intercrystalline sliding; in unconsolidated clayey rocks, the creep process includes water migration and movements of clayey particles; bituminous rocks, such as tar sands, are characterized by rock mass yielding, which occurs in particular at higher temperatures. Even solid rocks such as granite and limestone may creep as the result of deviatory stress activity, resulting in the formation and growth of new cracks. A change in deviatory stress may cause changes in the crack network because, after the initial closing of cracks, the old cracks will expand once again and new cracks will appear. A specific example of time-dependent deformations is also rock swelling, which is characteristic of anhydrite, certain types of shales, grey clay, etc... All these factors cause rocks in the phase of additional load to undergo both momentary and delayed deformation, the latter of which is time-dependent. This kind of rock is therefore referred to as viscoelastic or viscoplastic, provided the process occurs in a plastic area. Similar to elasticity, rocks can show different forms of nonlinearity, yet the majority of vis-coelasticity theories are based on the treatment of rocks as a linear, viscoelastic material. Creep, Dilatation and Compression Two principal factors essentially influence the mode of deformation and, in the final phase, the collapse of the rock mass. One of these is determined by the geotechnical properties of rocks, while the other depends on the size and speed of loading. Both processes are time-dependent, which means that for a realistic definition of rocks, time is a crucial factor to be considered in constitutive equations presenting the association between deformations and stresses. A typical time-dependent phenomenon found primarily in low-bearing-capacity and soft rocks is creep. Creep is defined as the irreversible deformation of rock mass in the period leading up to its collapse. In general, deformations resulting from creep depend primarily on three main parameters: time, temperature and stress. The influence of time on the development of time deformations is evident from the creep curve, i.e. as time versus a specific axial deformation, which is schematically shown in Figure 1. As is evident in this figure, the initial elastic deformation is followed by primary creep with a decreasing speed of deformations, then secondary creep, where the change in deformations is constant and tertiary creep, where the speed of deformations increases until final collapse. Temperature has a negative influence on the development of time deformations, as a rising temperature will increase the speed of creeping. An even greater influence on the development of time deformations is shown by load speed, which is reflected in the following facts: • comparatively speaking, a higher load speed causes smaller deformations, • a higher load speed gives a higher peak stress in smaller collapse deformations, • the yield limit and creep phenomenon already occur at very small loads. o =const. T=const. failure time ШШШЯ. e-axial strain a-uniaxial stress Г-temperature Mime I- primary state П-secondary state Ш-tertiary state Figure 1. Typical time dependent creep curve Slika 1. Značilna oblika krivulje lezenja How the volume of a rock mass will deform in the creep phase depends on the stress state dominating the rock. This is because the volume deformation of a sample may be positive (compression) or negative (dilatation). In an area with smaller stresses, the volume diminishes (contracts) due to the contracting or closing of micro cracks and pores. Areas with higher stresses will witness the irreversible growth of volume, as new micro cracks begin to form and the existing ones begin to expand. The compressibility and dilatation area obtained using the triaxial test is presented in Figure 2. In this figure, area Dc represents the compression area, and area Dd represents the dilatation area. The boundary between the two areas is called the dilatation limit. Another interesting figure in addition to the above-mentioned is Figure 3, which shows the development of volume deformations during an unconfined pressure test on a rock sample. The decreasing volume is evident in the first nonlinear part due to the closing of micro cracks and pores. This is followed G2 by the second, almost linear part between stresses C and I, with a reversible volume deformation. The last, nonlinear part is characterized by the opening and expansion of micro cracks, i.e. dilatation. Creep, Dilatation and Compression in the Vicinity of Tunnels Knowledge of the dilatation and compression areas in the vicinity of underground structures is of essential importance in their design and construction. Two parameters significantly influence the size and distribution of an individual area. These are: the relation between the horizontal and vertical stress components (ch/cv), and the effect of the primary supporting system. On the basis of laboratory tests and field measurements, we have arrived at the following conclusions on the behavior of rocks in the vicinity of tunnels and other underground structures: • a rock is much more unstable when it is c, ф с than when it is c, h 1 v h с the dilatation area diminishes substantially if the ch/cv ratio is higher and if the supporting is taken into account, creep is more rapid in the direction of the smallest soil pressure component, the convergence size depends on the ch/cv ratio, the height of the overburden, and the functioning of the supporting system. V2ai=V2CTi Figure 2. Domains of compressibility and of dilatancy Slika 2. Območje stiskanja in dilatacije сsi [МРа] 80 \ / 1 / 1 / ]/ 60 I 40 С ------У- 20 yy // // S A , , , i i i i ai - main stress e v - volumetrie strain I-C - linear area 0 0,02 0,04 0,06 0,08 6v [%] Figure 3. Stress strain curve showing dilatancy Slika 3. Razvoj volumskih deformacij pri enoosnem tlačnem preiz- Why is it important to have a knowledge of time-dependent deformations? In the construction of underground structures, a knowledge of time-dependent deformations will enable the following: • to select the proper rigidity of supporting, • to determine the sequence of excavations and supporting, • to predict a suitable time for incorporating the interior lining, • to determine the course of increasing load on the supporting, • to predict the period of eventual rehabilitation of the structure, • to forecast the long-term stable shape and size of the underground structure, • to determine the required over profile of the excavation, • to determine the areas where collapse may occur due to excessive deformations, etc. All the above-mentioned may be determined with some certainty, if, of course, we are able to correctly assess or forecast the time development of deformations. In doing so we shall have to consider the effect of interactions between the rock mass and supporting, as we are dealing with two materials (rock mass and supporting) that are both time-dependent, but do not behave in the same way in a specific time interval. In this contribution, we shall deal only with time-dependent processes in rocks that can be described using various rheological elements interconnected in various models. Burger's linear viscoelas-tic rheological model is presented in more detail below. BURGER's RHEOLOGICAL MODEL The dependence of normal specific deformations on time, also referred to as creep curves, which are obtained in laboratory or field investigations, may be described using various rheological models. In this case we shall limit ourselves to linear viscoelastic rheological models comprised of two basic rheologi-cal elements. These are Hook's spring and Newton's vessel, which are interconnected in various ways and, through these interconnections, determine various rheological models. Several basic linear viscoelastic rheological models are known, such as Maxwell's, Kelvin's, Generalized Maxwell's, Generalized Kelvin's, and Burger's model. The last mentioned is the most broadly accepted model in rock mechanics, as it best describes and presents the development of rock deformations in dependence of time. Burger's rheological model is obtained as a consecutive link of Maxwell's and Kelvin's rheological models, as shown in Figure 4. One can see that the model has four rheologi-cal elements, whose notation is as follows: • G : shear modulus, which controls the size of delayed elasticity, • G2: shear modulus, which defines the size of instantaneous elastic deformation, • nj dynamic viscosity, which determines the stage of delayed elasticity, • n2: dynamic viscosity, which describes the stage of viscose yielding, • Y1, Y2, Y3: shear strains. The response of time deformations with respect to the instantaneous and constantly active shear load т, begins with the instantaneous elastic shear strain y;, followed by the exponentially diminishing shear strain Y2, which then approaches the asymptote and continues into the constantly growing shear strain j3. In addition to the shear stress т, the sample may also be burdened with a normal load G. By increasing (decreasing) this load, the sample measures the axial specific deformations £, which is the laboratory procedure for determining the parameters of Burger's model. In this procedure, the cylindrical rock sample is subjected to a uniaxial pressure load by means of an instantaneous load Gj, during which the time development of specific axial deformations e; are measured. This is observed for as long as the creep curve does not approach the asymptote. The load is then increased and the procedure of strain measurement is repeated. The test is performed in several load stages, and for each stage a characteristic creep curve is obtained, as shown in Figure 5. v■ gi ni Kelvin body уз Gì Ц2 -шзч Maxwell body Figure 4. Burger's rheological model and a diagram of shear strains у versus time t Slika 4. Burgerjev reološki model in diagram strižnih specifičnih deformacij у v odvisnosti od časa t 81 : Tei шш® Si - axial strain t - time e о - creep curve intercept with ordinate 8 в - asymptote intercept with ordinate q - vertical distance between creep curve and asymptote Figure 5. Time dependent curve of the axial strains Slika 5. Krivulja osnih specifičnih deformacij v odvisnosti od časa t The size of axial specific deformations by time e/t) for the relevant Burger's model, burdened with constant axial load ap is presented using the equation: , . 2ст, ст. су, ст, . e, (t) = —- + + —---- ■ e 1 9 К 3 G2 3 G1 3 G1 "(G,'/ TI,) , CT1 + —W 3n2 (1) In this equation, the compression module K is independent of time and is calculated using the equation _K"=a1/3(81+283). The sizes of axial e; and transversal £3 strains are determined using resistance strain gages. The remaining parameters G p G2, n and ц2 are determined with the help of Figure 5 and the equations presented below. In this diagram, one can see that in time t=0, the curve bisects the ordinate at point e0 whereas in time t the curve approaches the asymptote, which has a gradient cjj /3r|2 and bisects the ordinate at point £B. On the basis of this data, the following three parameters can be calculated: 1 9 K 3G. 2 У (2) 3n2 2 1 1 9K + 3G^ + 3G1 n2 Gl (3) (4) If, in the above diagram, the distance between the curve and the asymptote is designated by q, then at a given moment of time t the semi logarithmic diagram log q may be drawn in dependence of time t. In this diagram (Figure 5) we obtain a straight line, which is presented by the equation: logtf = log f \ 3 Gx Gi 2,3-Л! (5) The first part of the given equation represents the intersection point of the line and the ordinate, which gives value G, and the second part of the equation represents the line gradient, which gives value пг G, 2,3-л, ili (6) In practice, the rheological model shown above can be satisfactorily used in the majority of cases to describe the curve of so-called secondary creep all the way up to the limit of tertiary creep. If we wish to describe the process of time-dependent creep in rocks, taking into account the plastic deformations, a more complex model will need to be selected, which may also be obtained by connecting additional rheological elements. The deficiency of the linear viscoelastic rheologi-cal model is primarily in the fact that it cannot be used to describe the dilatational and compressive specific deformations linked to collapse mechanisms in rocks. In such cases, the elastic viscoplastic rheological model may be used to describe time occurrences in the plastic area as well. Analysis of time-dependent DEFORMATIONS DURING TUNNEL construction in compressive low-bearing-capacity rocks In the text below, the behaviour of a tunnel during its construction, which took place in rheologically highly sensitive rocks (Figure 6) with varying geotechnical properties, is compared with a computer model of the time development of displacements in the tunnel tube walls. A typical example of such rocks are Permian-Carboniferous layers, which are comprised primarily of Figure 6. Geological site conditions of the covered area Slika 6. Geološka sestava analiziranega območja L«gsnd j ~J Tnctortc di) j "ТЙ~ j $J«lDne and diyslone т«Иш inno.lem «»»ttwed гот» Wots г appea rance x droppmo Y IMt v, bVnm) M 3-1 ЕялЬкЛ nHlUI SN. Aawimcr dr ±СЙ?П molded shaley claystones, tectonic clay and siltstones intercalated with various clay minerals, which in reality provide a physical basis for the interpretation of more or less intensive creep. The description of time deformations is performed using an appropriate rheological model, but one should bear in mind that we are dealing with two time-dependent systems in interaction. These are the rock strata base as the principal medium, and the primary lining comprised of sprayed concrete and other supporting elements, such as rock bolts, steel supports, etc. In the case discussed, only the rheological properties of the rock mass have been taken into account, while the supporting system is treated as an elastic structural element comprised of sprayed concrete or supports. In the analyzed practical example, equations were used within the scope of a simple analytical method, the so-called closed form solutions[1]. With the help of these equations and measured displacements of the roof measuring point in the tunnel tube, the rheological parameters of surrounding rocks in the analyzed profile were determined by means of a back analysis. The procedure used in the above-mentioned analysis is based on the use of Burger's model and the Generalized Maxwell's model. Because the parameters of surrounding rocks were not known for the above-mentioned two models, a back analysis was used. Taking into account the actual variability and structural damage of Permian-Carboniferous rocks, and indirectly also the interwoven ness of their individual lithological types, the employed method of determining parameters has, in comparison with classical methods (laboratory, in situ with dilatometer or load plate), several advantages. These are the following: • problem of acquiring adequate samples for conducting creep tests is eliminated, • dependence of creep parameters on the structure of tested samples is also excluded, and • application of laboratory-measured values of creep parameters on the broader rock mass areas is not necessary. Pi Pi t m t Pi - primary horizontal stress P2 - primary vertical stress a - hole diameter r - radial point distance 9 - radial point angle P2 Figure 7. Cross section of an unlined tunnel tube Slika 7. Shematski prikaz stanja pred vgradnjo primarne obloge v predorsko cev The back analysis was conducted by dividing the curve of measured displacements in the analyzed profile into three parts, each of which was examined separately. For the entire displacement curve we therefore obtained: • initial displacements occurring immediately after excavation (using Kirsch's equation for circular opening, Figure 7). • displacements occurring in the period from the excavation of the calotte until the incorporation of the complete primary lining of the tunnel (using equations for describing the creep of rocks around the unsupported tunnel, Figure 7). • displacements occurring after the completed incorporation of primary lining along the entire circumference of the tunnel tube (using equations for describing the creep of rocks around the supported tunnel, Figure 8). For the curve of measured displacements, we took the measured vertical displacements in the left (south) tunnel tube, on the west part of the Trojane tunnel, at cross sections 86, 87, 88 and 89. Relevant data are available in the Report on geological and geotechnical monitoring of the Trojane tunnel excavation no.151[4]. It should be mentioned that an initial displacement u0 was added to the measured displacements. This displacement is of the same size as the one used in the curve of calculated displacements. However, it is not included in the measured values, as it occurs before the incorporation of measuring points in the analyzed measuring profile. The equations used for the calculation of displacements are presented in[1] and have the following form: Initial displacement: pa Щ = 2 G (7) Po ■ Po Po - initial stress a - internal tunnel radius b - external tunnel radius Figure 8. Cross section of a lined tunnel tube Slika 8. Prikaz predorske cevi z vgrajeno primarno oblogo An unlined tunnel displacement: *r(t) = A + B v2 Ar' j G2 Gl r|2 Ä=Pi+Pi a 4 r CL В — (pj -p2)—cos20 r A lined tunnel displacement: рьеГ*) (9) (10) (11) G, 2 0 = ^ G, 1 t^äs2 + G' \ +VÌ + Gv /П2 (i -»i) 1+Vì+Gy (12) Vi) /Th г л л (13) (l-2v')62+a 2 _2 v 2 . 2Л 5 + — = 0=>Г15Г2 П2 (14) b -а у (15) _ _ b2rpb (l - 2v ' + a2 j r2) 2G'(62-fl2) u=- for ab (8) With the help of back analyses and the iteration of various parameters, n, П2, G1 and G2, we obtained diagrams showing the measured and calculated vertical displacements of roof measuring points in the above-mentioned measuring cross profiles. On the basis of calculations performed, diagrams shown (Figure 9) and relevant analyses, we may summarize as follows: • The curve of measured values may be easily followed until approx. day 13, when the primary lining in the tunnel tube was completed. From here on the supported tunnel equation was used, in which we observed a sharp rise in displacements in dependence of time, followed by rapid stabilization. Roof displacement of point P In tunnel section 86 0 ? 1- E -200 fc -250 Я n » -350 o -400 -450 Time [day] Roof displacement of point P In tunnel section 87 Time [day] Roof displacement of point P in tunnel section 88 Time [day] Roof displacement of point P In tunnel section 89 Time [day] Figure 9. Comparison between measured and calculated vertical displacements of a roof point Slika 9. Primerjava med izmerjenimi in izračunanimi pomiki stropne točke Since the phase of support creeping of primary lining was not taken into account in the supported tunnel equation, which means that its constant solidity and rigidity is assumed from the moment of incorporation, the description of displacements in this phase is not entirely realistic because a certain average value was used. This equation is thus applicable in cases when a tunnel is supported by prefabricated, reinforced concrete segments, which are frequently used in construction works where TBM machines (for cutting the entire tunnel profile) are used. The average values of rheologi-cal parameters for the above-mentioned profiles are: G;=5,5MPa, G2=115MPa, n,=65000MPa^min, n2=5,05-108MPa^min. It should be mentioned that the average maximum displacements in the analyzed area were approx. 360 mm. The established values of rheological parameters were considerably lower than those normally obtained in laboratory tests. It should be taken into account that the excavation of the tunnel tube was performed in a rock mass with low strength and deformability properties, which indirectly called for the immediate incorporation of supporting elements. It is evident from the measuring data that the curves of measured time-dependent displacement are of varying shape and size in the observed time period. This is due to the geological composition and structure of surrounding rocks, which are characterized by rapid changes both as regards the content of individual lithological components and the position of rock strata. In the given case, it was thus practically impossible to obtain representational rheological parameters of existing rocks in the laboratory. Based on the above-mentioned, we may conclude that describing the time development of deformations in rocks depends on a large number of influential factors which are difficult to include in calculations or whose interrelations are hard to determine. The procedure used in the given case may be suitable for the preparation of preliminary analyses of more simple cases of creep, which by their complexity do not surpass the cross section of an underground structure or the structure of the rock mass. Part of the complexity of a specific problem may be solved by means of numerical methods, which are available within the scope of complex software applications. Conclusions • Time-dependent processes in rocks which, depending on natural conditions, are more or less intensive play a significant role in the construction of underground structures. These processes indirectly influence the design and execution of construction works, including the supporting method, and have a long-term effect on the stability of the structure. • Typical time-dependent occurrences in rocks often have the character of creeping soft and low-bearing-capacity rocks or rock mass containing soils. • Typical rock masses with distinctive rheological properties are also Permian-Carboniferous layers, which can be found in several areas throughout Slovenia, such as in the Karavanke mountains, Idrija, Mežica, Trojane, Ljubljana (Golovec hill, Šentvid), and elsewhere. • The presented practical example of the use of viscoelastic rheological models in the calculation of time-dependent displacements of tunnel tube walls has opened the question of the applicability of such calculations in practice. • The analyzed comparisons between measured and calculated values of displacements professionally justify the presented calculation methods alongside sufficiently known simplifications and assumptions. • Quick calculations coupled with practical experience are adequate bases for rough estimates of the method of primary supporting of underground structures being built in rheologically sensitive rocks. • In describing the creeping of rock masses, it would be necessary to use, for supported underground structures, a more detailed equation that would also take into account the creep of a support system made of sprayed concrete cement or any other time-dependent support system. POVZETEK Časovno odvisni procesi v kamninah Poznavanje časovno odvisnih procesov v kamninah, je z inženirskega vidika zelo pomembno. V mislih imamo procese, ki zajemajo časovni razvoj napetosti in deformacij v hribinah in okolici podzemnih objektov. Ti procesi, ki so dolgotrajni in se lahko odvijajo več dni ali celo desetletij, vplivajo na spremembe in prerazporeditve napetosti v hribinah v katerih so zgrajeni podzemni prostori. Posledice tega so med drugim povečanje obremenitev podpornega sistema oz. zmanjšanje stabilnosti objekta, kar v skrajnem primeru lahko privede celo do porušitve. Dejavnike, ki povzročajo omenjene spremembe napetosti in deformacij v kamninah gre pripisati različnim vzrokom. Med najpogostejše štejemo spremembe obtežb ali hribinskih pritiskov, ki delujejo v kamninah in so lahko posledica pretakanje vode, spremembe geometrije izkopanega prostora, preperevanja in podobno. Drugi pomembni dejavnik, ki prav tako povzroča časovno odvisne procese v kamninah pa je lezenje, čigar vzroke lahko razložimo s tremi glavnimi vplivi. To so plastično tečenje hribinskih mas, širjenje vezanih in nastajanje novih razpok ter nabrekanje. Vsi ti dejavniki povzročajo, da kamnine v fazi dodatne obremenitve, poleg trenutne deformacije, kažejo tudi zakasnelo - časovno odvisno deformacijo, ki je lahko različno velika tako po obsegu kot tudi po času trajanja. Kamnine ali širše gledano hribine, ki imajo te lastnosti, imenujemo viskoelastične oz., v kolikor se ti procesi odvijajo v plastičnem območju, tudi viskoplastične. Poznavanje časovno odvisnih sprememb deformacijsko napetostnega polja v okolici podzemnih objektov, je z vidika načrtovanja in gradnje podzemnih objektov velikega pomena, saj nam omogoča pravilnejšo izbiro togosti podporja, določitev zaporedja izkopa in podpiranja, napovedovanje primernega časa vgradnje notranje obloge, določiti potek naraščanja obremenitve podporja, določiti potreben nadprofil izkopa prostora, itd. Eno od pomembnih področij znanstvene vede, ki je se ukvarja s časovno odvisnimi procesi v hribinah, je tudi razvoj in preizkušanje reoloških modelov, s katerimi opisujemo časovno odvisne napetostno deformacijske spremembe v hribinskih sistemih. V pričujočem delu smo se omejili na linearne viskoelastične reološke modele, med katerimi je Burgerjev model dobro uporaben v mehaniki kamnin. Ta model je določen z zaporedno vezavo Maxwellovega in Kelvinovega reološkega modela. Lastnosti modela podajata dva elastična in dva viskoelastična parametra G, G2, n in n2, katere določimo s pomočjo krivulje lezenja, dobljene na osnovi laboratorijskih oz. in-situ raziskav. Poznavanje omenjenih parametrov, lahko uporabimo za napovedovanje časovnega razvoja deformacij hribine, izpostavljene določenemu napetostnemu stanju ali spremembi napetosti. Ker je določitev viskoelastičnih parametrov v laboratoriju oz. in-situ v posameznih primerih lahko vprašljiva, se v ta namen pogostokrat poslužujemo povratne analize, kjer se na osnovi poznanih oz. izmerjenih vrednosti npr. pomikov določenih točk ostenja podzemnega prostora, z iteriranjem poišče iskane realne vrednosti. Ta način dela je prikazan tudi v pričujočem prispevku, kjer smo s pomočjo povratne analize poiskali viskoelastične parametre za Burgerjev in posplošeni Max-wellov model. Navedena reološka modela se uporabljata za napovedovanje časovnega razvoja deformacij nepodprtega in podprtega predora krožnega prereza. Enačbe omenjenih modelov so podane v[1] in spadajo v kategorijo t.i. preprostih analitičnih enačb zaprte oblike. Ker gre za analitične enačbe, ki opisujejo dogajanje v okolju, ki je izjemno kompleksno in odvisno od številnih parametrov, seveda ni za pričakovati popolnega ujemanja med napovedanimi in izmerjenimi vrednostmi. V pričujočem prispevku je obdelana tematika, ki obravnava v kolikšni meri so omenjene enačbe za napovedovanje časovnega razvoja deformacij nepodprtega in podprtega predora uporabne ter kolikšne so vrednosti viskoelastičnih parametrov analiziranega območja. Analizirano območje, skozi katero je potekala gradnja predora sestavljajo permokarbon-ske kamnine, med katerimi prevladujejo pregneteni skrilavi glinavci, tektonska glina in meljevci z različnimi vsebnostmi mineralov glin. Omenjene kamnine imajo izrazite reološke lastnosti in jih lahko srečamo širom Slovenije, kot npr. v Karavankah, Idriji, Mežici, Trojanah, Ljubljani (Golovec, Šentvid) in drugod. Povratna analiza je potekala tako, da smo s pomočjo iteriranja dosegli ujemanje med krivuljo izračunanih in krivuljo izmerjenih pomikov. Krivuljo izračunanih pomikov smo dobili kot vsoto treh različnih pomikov, katere podajajo tri različne enačbe. To so začetni elastični pomik, viskoelastični pomik nepodprtega predora in viskoelastični pomik podprtega predora. Za krivuljo poz- nanih vrednosti pa smo privzeli izmerjene vertikalne pomike ostenja predora v štirih zaporednih prečnih profilih na analiziranem odseku predorske cevi. Na osnovi primerjave rezultatov in oblike krivulj lahko ugotovimo, da enačba časovnih deformacij nepodprtega predora lepo sledi izmerjenim pomikom, dočim pri uporabi enačbe podprtega predora pride do manjšega odstopanja. Vzrok slednjemu je dejstvo, da imamo v našem primeru opravka z dvema časovno odvisnima materialoma, to je hribino in podporjem. Ker v enačbi podprtega predora ni upoštevana faza lezenj a podporja oz. primarne obloge, kar pomeni, da je privzeta njegova konstantna trdnost in togost od trenutka vgradnje, opisovanje pomikov za to fazo ni povsem realno, saj upoštevamo določeno povprečno vrednost. Enačba za izračun pomikov podprtega dela predora je zato bolj uporabna v primeru podpiranja predora s prefabriciranimi armirano betonskimi segmenti, kateri se pogosto uporabljajo pri gradnjah z uporabo strojev za rezanje celotnega profila predora (TBM). Absolutne velikosti viskoelastičnih parametrov imajo precej nižje vrednosti, kot jih dobimo iz laboratorijskih preiskav. Upoštevati je potrebno dejstvo, da je izkop predorske cevi potekal v izjemno heterogeni hribini z nizkimi trdnostnimi in deforma-bilnostnimi lastnostmi, kar je posredno narekovalo takojšnjo vgradnjo podpornih elementov. Poleg tega je omenjeno dejstvo povezano tudi z geološko sestavo in strukturo okoliških hribin, za katere je značilno hitro spreminjanje tako glede zastopanosti posameznih litoloških členov, kot tudi glede lege hribinskih plasti. Iz vsega podanega lahko povzamemo, da je opisovanje časovnega razvoja deformacij v hribinah povezano z velikim številom vplivnih dejavnikov, ki jih je v izračunih težko v popolnosti zajeti in poiskati njihove medsebojne povezave. Postopek, ki je bil uporabljen v obravnavanem primeru, je uporaben za izdelavo preliminarnih analiz enostavnejših primerov lezenja, ki po svoji kompleksnosti ne presegajo niti oblike prečnega profila podzemnega prostora niti strukture hribinske zgradbe. Del kompleksnosti določenega problema, ki je prisoten pri analiziranju časovno odvisnih pojavov pri gradnji podzemnih prostorov, je rešljiv z numeričnimi metodami, ki so danes na voljo v sklopu zahtevnih programskih orodij. References [1] Richard E. Goodman: Introduction to Rock Mechan- ics, 2nd edition, New York, 1989; [2] N. Cristescu: Rock Rheology, Dordrecht, 1989; [3] B.H.G Brady & E.T. Brown: Rock Mechanics For Underground Mining, 2nd edition, Dordrecht, 2004; [4] Geološka in geotehnična spremljava izkopa predora Trojane; Izvajalec del: Grassetto S.p.A,-151 poročilo, Ljubljana, 2003; Možnost izvedbe visokotlačnega podzemnega skladišča zemeljskega plina na območju Rudnika Senovo High Pressure Storage of Gas in Area of Coal Mine Senovo Željko Vukelić1, Željko Sternad2, Vladimir Vukadin2, Franc Cadež2, Marjan Hudej3, Ivan PeCovnik3 'Naravoslovnotehniška fakulteta, Aškerčeva 12 Oddelek za geotehnologijo in rudarstvo, 1000 Ljubljana, Slovenija; E-mail: zeljko.vukelic@ntf.uni-lj.si 2Inštitut za rudarstvo, geotehnologijo in okolje, Slovenčeva 93, 1000 Ljubljana, Slovenija; E-mail: zeljko.sternad@i-rgo.si, vladimir.vukadin@i-rgo.si 3RGP, Rudarska 6, 3320 Velenje, Slovenija; E-mail: marjan.hudej@rlv.si, ivan.pecovnik@rlv.si Received: November 05, 2006 Accepted: November 14, 2006 Povzetek: V članku smo predstavili možnost izgradnje podzemnega skladišča zemeljskega plina (PSZP) v karbonatnih kamninah na področju rudnika Senovo. Področje je bilo geološko preiskano. Izvedenih je bilo pet strukturnih vrtin do maksimalne globine 279 m. Jedro iz vrtin je bilo popisano s poudarkom na stratigrafici, razpokah, tektonskih prelomov, RQD ...., vzeto pa je bilo veliko število vzorcev za laboratorijske preiskave. V vrtinah smo izvedli geofizikalne, presiometrične in hidrogeološke preiskave. S preiskavami smo potrdili območje (cca. 16,000 m2), kjer je pod globino površine 150 m, možno izdelati do štiri komore za podzemno skladišče zemeljskega plina. Abstract: A paper for underground storage of gas (PSZP) in carbonate rocks was carried out in the area belonging to the Senovo mine. The area was geological surveyed and in addition five structural boreholes were drilled up to the depth of 279 m. The cores were logged with emphasis on stratigraphy, layering, rock joints, tectonic zones, RQD and addition characteristics samples were taken for the laboratory investigations. In boreholes geophysical, pressiometric and hydrogeological investigations were also carried out. The results of the investigations have revealed the occurence of a rock volume (area of 16.000 m2) of 150 m where the geological and geotechnical conditions are appropriate for construction of several (up to 4) gas chambers for underground storage of gas. Ključne besede: podzemno skladišče zemeljskega plina (PSZP), karbonatne kamnine, prevlečena podzemna komora Key words: underground storage of gas (PSZP), carbonate rocks, The Lined Rock Cavern UVOD Slovenski plinovodni sistem ima skladišča zemeljskega plina zakupljena v tujini. Termoelektrarna Brestanica (TEB) je eden večjih porabnikov zemeljskega plina v Sloveniji , s svojim načinom delovanja kot tipična konična elektrarna z velikimi urnimi in dnevnimi odjemi, pa povzroča v relativno majhnem plinovodnem omrežju precejšnje težave, posebno še v zimskem času. Takrat se pojavljajo zaradi velikega odjema plina 304 VUKELIĆ, Ž. ET AL. tudi omejitve pri obratovanju TEB. Tako smo v letu 2005 pričeli s terenskimi in laboratorijskimi raziskavami na področju Rudnika Senovo v zapiranju. Raziskave so vsebovale geološko kartiranje površine, strukturno vrtanje petih globokih vrtin na jedro, terenske geotehnične meritve v vrtinah (presiometer, geofizikalne meritve, hidrogeološke meritve) in laboratorijske preiskave jedra vrtin za določitev njihovih geomehanskih parametrov. Na območju , kjer smo opravili raziskave prevladujejo apnenci, dolomiti in breče. Z opravljenimi raziskavami smo potrdili možnost izgradnje visokotlačnega podzemnega skladišča zemeljskega plina (PSZP) po tehnologiji LRC (Lined Rock Cavern). Pri PSZP se najprej izdelajo trije pristopni tuneli v treh različnih nivojih. Po izvedbi pristopnih tunelov se prične z izkopom podzemne komore projektiranih dimenzij. Nato se izvede jekleni plašč komore (debelina plašča obloge je 10 - 15 mm). Prostor med hribino in jeklenim plaščem se zalije z betonom. Podzemna komora je s površino povezana z vertikalnim jaškom v katerem so cevi za polnjenje, hlajenje in praznenje plina iz podzemnega skladišča. Na površini je objekt s pripadajočo elektro-strojno opremo, ki zavzema površino 350 m x 300 m. Tehnologija izgradnje je povzeta po projektu PSZP na Švedskem, kjer tako skladišče že obratuje s tem, da je skladišče izdelano v granitnih kamninah. OPIS TEHNOLOGIJE LRC PODZEMNEGA SKLADIŠČA PLINA Na švedskem so od leta 1960 intenzivno raziskovali možnost za izgradnj o visokotlačnega podzemnega skladišča plina.[1] Raziskave so bile usmerjene predvsem v možnost skladiščenja v globokih vodonosnikih in opuščenih vrtinah za nafto in plin. Ker se je izkazalo, da v omenjenih variantah ni možno skladiščiti plina, so zadnjih dvajset let intenzivno raziskovali v smeri LRC (The Lined Rock Cavern - z oblogo prevlečen podzemni prostor/ skladišče). Tako danes obratuje podzemno skladišče v Skallenu od začetka leta 2003. LRC demonstracijski projekt je izveden blizu obalnega mesta Halmstad na severozahodnu Švedske. Objekt leži blizu glavnega plinovoda, ki poteka ob zahodni obali Švedske in ima odlično izhodišče za oskrbo trga s plinom. Gradnja skladišča se je pričela leta 1998. Načrtovanje LRC podzemnega skladišča in izgradnja skladišča Podzemna komora izkopa je bila načrtovana s strani strokovnjakov NCC iz Göteborga v sodelovanju z investitorjema Sydkraft in Gaz de France. Projekt je izveden na podlagi več letne študije, ki je definirala LRC (angl. Lined Rock Cavern, sl. Prevlečena podzemna komora) koncept. Načrt podzemnega skladišča je bil skrbno pregledan in odobren s strani švedskega pooblaščenega vladnega organa. Obenem so LRC koncept revidirali strokovnjaki ameriškega Ministrstva za energijo in ga predstavili kot možno opcijo za ameriško tržišče. Rezultati revizije so vzdržali presojo o izvedljivosti projekta in so predstavljeni v letnih poročilih ameriškega Ministrstva za energijo (U.S. Department of Energy,2001; U.S. Department of Energy,2002). PSZP je izdelano v granitnih kamninah. Izvedba skladišča, od podzemne gradnje, pa do inštalacije elektro-strojne opreme, Preglednica 1. Dimenzije podzemne komore Table 1. Dimension of storage cavern Skupni volumen plina lOMNm3 Volumen skladišča 40 000 m3 Premer skladišča 37 m Višina skladišča 50 m Tlak 200 bar Globina skladišča pod površino 115 m Čas polnjenja skladišča 20 dni Čas praznjenja skladišča 10 dni je trajala približno 4 leta. Ker je šlo v tem primeru za razvojni projekt je gradnja trajala nekoliko dlje kot bi bilo to pri običajni izgradnji tovrstnega skladišča (predvidoma dve leti). Pri podzemnem skladišču plina se najprej izdela pristopni tunel, ki je povezan s tremi pristopnimi tuneli v treh različnih nivojih. Tuneli so namenjeni za transport materiala med izgradnjo podzemne komore. Po izvedbi pristopnih tunelov se prične z izkopom podzemne komore projektiranih dimenzij (slika 1, preglednica 1). Na površini je objekt s pripadajočo elektro-strojno opremo, ki zavzema površino 350 x 300 m. Izdelava podzemne komore oziroma podzemnega skladišča se je pričela z izkopom dostopnih tunelov. Tuneli in komora so izkopani v gnajsu. Najprej je bila izkopana zgornja kalota komore. Nato so nadaljevali z izkopom do dna komore. Izkop se je izvajal z miniranjem. Po končanem izkopu komore so na stene pritrdili drenažen cevi in jih zaščitili z brizganim betonom. Po izkopu komore so pričeli znotraj komore z montažo prosto stoječe jeklene obloge - posode. Jeklena obloga je varjena in je sestavljena iz prefabriciranih jeklenih plošč povprečne debeline 12 mm. Izjemen poudarek je bil na izvedbi varjenja in kvaliteti jeklene obloge. Zvari jeklenih plošč so bili 100 % pregledani z neporušitvenimi metodami. Vso varjenje in kontrola zvarov je bila opravljen do zaključka izdelave obloge. Vertikalna dvigala so bila uporabljena za dviganje posode. Zadnja faza izgradnje PSZP je bilo polnjenje prostora med j ekleno oblogo in steno izkopane komore z betonom. Uporabljen je bil kvaliteten beton, ki ga ni bilo potrebno vibrirati. Posoda se je naponila z vodo tako, da se je vzpostavilo hidrostatično ravnovesje med samim polnjenjem prostora med jekleno oblogo in steno izkopane komore z betonom. Podzemna komora je povezana s površino v vertikalnim jaškom, ki je bil izvrtan. V jašku so jeklene cevi za polnjenje in praznjenje skladišča plina. Oprema za vtiskanje plina v podzemno skladišče je enaka opremi kot se uporablja pri podzemnih skladiščih plina, ki so izdelani v opuščenih rudnikih soli. PSZP je vodeno iz kontrolne sobe, ki je na površini in bo v bodoče povezano s centralnim kontrolnim objektom plinovodnega omrežja v Malmöju na Švedskem. 306 VuKELIć, Ž. ET AL. Izgradnja PSZP je bila končana poleti 2002. Po izgradnji so pričeli s testiranjem podzemnega skladišča in obremenjevanjem komore s tlakom do 22 MPa. Izvajali so monitoring hribine in jeklene obloge podzemnega skladišča med obremenilnimi testi. Preliminarne raziskave so pokazale, da so deformacije hribine in jeklene obloge nekoliko nižje kot so jih predvideli pri načrtovanju objekta. V začetku leta 2003 so vključili podzemno skladišče plina v plinovodno omrežje Švedske. Geološke razmere v okolici Rudnika Senovo v zapiranju Podatki pridobljeni z geološkim kartiranjem ter geološkim popisom jedra vrtin, potrjujejo Slika 1. Shematski prikaz podzemnega skladišča zemeljskega plina PSZP (C. Noren &, 2006)[3] Figure 1. Layout of storage cavern PSZP nastopanje apnencev in dolomitov na vzhodnem območju Rudnika Senovo.[2,4] V vrtinah se pretežno menjavajo sivi do temno sivi apnenci in dolomiti s sivorumenimi brečami. V apnencih in dolomitih se često pojavljajo tanke nekaj mm do nekaj cm debele pole zelenkastih laporjev. Kamnine so zato plastovite. Breče imajo peščeno karbonatno vezivo, kjer je vezivo peščeno lapornato, te breče hitreje razpadajo in imajo slabše geomehanske karakteristike. Prehodi med apnenci in dolomiti so mestoma zvezni mestoma pa so vezani na cone breč. Kamnino presekata navadno 2 sistema razpok, ki jih običajno zapolnjuje kalcit, redkeje se v njih pojavlja lapor. Nekatere žilice so izvotljene, v njih nastopajo drobni kristalčki. Prostorski odnosi med plastovitostjo in dvema sistemoma razpok, ki presekata plasti pod skoraj pravim kotom so lepo vidni na sliki 2. Na površju smo ugotavljali zelo spremenljive vpade, ki so posledica sedimentacijskih razmer, lokalno pa tudi posledica gubanja majhnega merila. V vrtinah se večinoma pojavljajo zmerni do strmi vpadi med 45 in 90°. Že omenjene razpoke so običajno približno pravokotno orientirane med seboj in na plastovitost. Širina diskontinuitet je med 1mm do nekaj centimetrov, njihova medsebojna oddaljenost pa se spreminja od 0,1 do 1 dm in več. Mestoma se pojavlja tudi tektonska breča, kjer so kosi apnenca, dolomita in laporja sprijeti v meljasto peščeni osnovi. Tektonsko pretrto jedro smo v krajših odsekih opazovali v vrtinah V-4, V-5 in V-2, kjer pripada manjšim lokalnim prelomom. Večji prelom pa povzemamo z rudniške geološke karte, to je Reštanjski prelom, ki se nahaja na vzhodnem robu karte, ob njem pa so bile oligocenske plasti premaknjene za cca 200 m proti severozahodu. Slika 2. Plast apnenca na površini z dvema sistemoma razpok Figure 2. Layer of limestone with two crack system 308 VUKELIĆ, Ž. ET AL. Potencialno primeren odsek za izvedbo podzemne komore, se na podlagi raziskav v vrtini V-1, in nato posledično na ostalih vrtinah, nahaja med globino 196 m in 276 m. V tem delu se zgoraj pojavljajo apnenci spodaj pa dolomiti, ki so močneje razpokani, pogostejše so v njih tudi tanke laporne pole. Razpoke imajo subvertikalno do položno lego, zapolnjene so s kalcitom, ponekod tudi z laporjem. Povprečna vrednost enoosne tlačne trdnosti za ta odsek je znašala 55 MPa, RQD 47 %. Za primerjavo povejmo, da ima odsek nad tem, to je med 143 in 196 m vrednosti с = 23 MPa, RQD = 29 %. Vrednost RMR za predlagani odsek tako znaša 48, GSI 40. Po vrednosti RMR uvrščamo ta del v III. skupino s srednjo kvaliteto hribine. Za zgornji odsek so vrednosti RMR/GSI 37/30, karje po RMR IV skupina s slabo kvaliteto hribine. Terenske preiskave Vse vrtine so bile geološko-geotehnično popisane, pri čemer smo poleg litologije popisovali razpoke: njihovo usmeritev, debelino, polnilo in pogostnost. Izmerjen je bil RQD jedra, posebaj pa smo izdvojili pojavljanje pretrtih con ter pojave različnih mineralov (pirit, železovi oksidi in hidroksidi, ter kalcit). Iz vrtin so bili odvzeti vzorci za laboratorijske preiskave, v samih vrtinah pa so bile izvedene različne geotehnične in hidrogeološke preiskave. Presiometrske preiskave Presiometrske preiskave so bile izvedene v vrtinah V2 in V4. Rezultati so pokazali, da se moduli elastičnosti (E0) v vrtini V2 gibljejo v razponu od 0.103 GPa do 44,9 GPa, ter od 0,295 GPa do 71,36 GPa v vrtini V4. Nižje vrednosti so značilne za apneno-dolomitne breče z glinasto-lapornim vezivom, glinavce in laporje, ter močno razpokane kamnine, višje vrednosti pa za kompaktne dolomite, apnence in breče s karbonatnim vezivom. Za močneje razpokane kamnine in kamnine z nižjim modulom elastičnosti je značilno, da je razbremenilni modul (Eur) do 10 krat višji od obremenilnega, za kompaktne kamnine pa je razbremenilni modul 2-3 krat višji. Primerjava rezultatov meritev elastičnih modulov s presiometrom (E0) in modulov izmerjenih v laboratoriju (E), kaže da so razponi in velikostni red izmerjenih vrednosti podobne. Direktna primerjava med izmerjenima moduloma je bila možna le v vrtini V2 in sicer na globini 192,5, kjer se pojavljajo brečasti karbonati z različnim vezivom. Vrednost izmerjena s presiometrom znaša 8,3 GPa, v laboratoriju pa smo dobili vrednost 66,9 GPa. Vzrok za tolikšno odstopanje je v dejstvu, da smo s presiometrom izmerili elastični modul hribine, pri čemer na rezultat posredno vplivajo prostorske variacije, kot so razpokanost, spremembe litologije itd... Vpliv prostorskih variacij je na laboratorijskem vzorcu bistveno manjši zaradi česar je modul višji. S presiometričnimi meritvami se bolj približamo dejanskemu modulu kompaktne kamnine z razbremenilnim modulom, (E ), ' v ur7' ki v tem primeru znaša 42,6 GPa, kar je veliko bližje laboratorijski vrednosti. Del rezultatov preiskav iz vrtineV4 so povzeti v preglednici 2. Preglednica 2. Rezultati presiometrskih meritev v vrtini V4 Table 2. Pressiometric tests in well V4 Zap.št. Vrtina Globina Б0 Eur(l) Eur(2) H H/V Eo/Eur m obremenilni GPa razbremenilni GPa razbremenilni GPa MPa 1 V4 163,5 71,36 2,63 0,60 0,00 2 V4 164,5 10,85 40,81 2,49 0,56 3,76 3 V4 165,5 51,71 76,65 2,50 0,56 1,48 4 V4 166,5 3,82 31,70 2,54 0,57 8,30 5 V4 167,5 26,10 61,66 2,70 0,60 2,36 6 V4 168,5 2,74 19,25 2,47 0,54 7,03 7 V4 196,5 0.29 0,85 1,2 3.03 0,57 2,92 8 V4 197,5 0,91 3,13 1,9 4,70 0,88 3,45 9 V4 198,5 3,17 7,20 5,0 4,09 0,76 2,27 10 V4 199,5 1,80 8,5 2,90 0,54 0,00 Geofizikalne meritve Na območju predvidene izgradnje PSZP so bile izvedene tudi geofizikalne preiskave in sicer seizmični crosshole ter geoelektrični crosshole med obstoječimi raziskovalnimi vrtinami. Izmerjene so bile 2 seizmični in 2 geoelektrični preslikavi. Cilj preiskav je bil ugotoviti morebitne anomalne cone v pretežno karbonatni kamnini, ki jih MPa 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00 90,00 163,5 164,5 165,5 166,5 — 167,5 n C o 168,5 o> 196,5 197,5 198,5 199,5 - 1 - - 1 - ^-- _! 1 -1-1- b 1 1 i b 1 1 □ □ E0 □ Eur Slika 3. Rezultati presiometrskih meritev v vrtini V4 Figure 3. Pressiometric tests in well V4 310 VuKELIć, Ž. ET AL. Preglednica 3. Rezultati nalivalnih preizkusov v vrtinah V2, V3 in V4 Table 3. Groundwater tests in wells V2, V3 and V4 Vrtina V2: Datum izvedbe Globina izvedbe (m) Izračunan K (m/s) 22. 2. 2006 90,3-99,3 1,64*10"® 12. 3. 2006 150-172 9,38*10"5 16. 3. 2006 201-213 б.ЗШО"5 Vrtina V3: Datum izvedbe Globina izvedbe (m) Izračunan K (m/s) 11.4. 2006 146 -152 1,41*10"5 18. 4. 2006 174-186 1,35*10"5 Vrtina V4: Datum izvedbe Globina izvedbe (m) Izračunan K (m/s) 18. 4. 2006 154 -160 2,58*10"® povzročajo nekatere plasti klastičnih usedlin, predvsem laporni in skrilavi sedimenti. Z geofizikalnimi preiskavami nismo ugotavili obstoja večjih prelomnih con. Hidrogeološke preiskave V okviru hidrogeoloških preiskav smo v vrtinah V2, V 3 in V4 izvedli nalivalne preizkuse v različnih globinah. Poleg tega pa smo izvedli serijo meritev nivoja gladine podtalnice. Rezultati nalivalnih preizkusov, ki so prikazani v preglednici 3 so bili ovrednoteni po različnih metodah (po HVORSLEV-u in po SCHNEEBELLI-ju). Na osnovi izmerjenih vrednosti lahko preiskovane kamnine uvrstimo med srednje prepustne s koeficienti prepustnosti med 10-5 in 10-6 m/s. Laboratorijske preiskave V okviru laboratorijskih preiskav smo na vzorcih odvzetih iz vrtin opravili naslednje preiskave: • enoosne tlačne trdnosti (oc ); • enoosne natezne trdnosti (ot); • prostorninske teže(y); • modula elastičnosti (E); • poissonovega koeficienta (v). Rezultati laboratorijskih preiskav v vrtini V4 so podani v preglednici 4. 2 n > > й M ft гй g. S Л - Is 1 o ? ■§ .s 3 s N U & « CJ 'iS ■e i? о "оз о ■§ J M ■— ^ -о Jr S Рч H Poissonov količnik > ■ 0,16 I 0,2 I 0,28 1 T— o" 0,22 I 0,27 I 0,12 I Modul elastičnosti (0 Ш L 85080 54330 86670 98520 80000 61150 53600 Trdnost Zemljine Enoosna natezna VAU a 4,3 I 2,4 I CM" 0,3 I 3,3 1 2,7 I 2,9 I 5,5 I 6,8 I см" 4,3 I ю" 4,7 I 6,5 I 4,7 I 7,2 I 0,2 I Enoosna tlačna VALJ a 58,9 1 73,5 I 1,00 I 51,80 I 7,7 I 22,3 I Tf T— 65,9 1 42,6 I 71,9 I 62,8 I 76,4 I 7,8 I 22,4 I 58,2 I 49,0 I 70,1 I 57,8 I 25,9 I 41,9 I CO. t— Prostominska teža suhega materiala a i JC lo со CM I 26,6 I 22,7 I 26,4 I 26,2 I 25,8 I 22,3 1 26,4 I 26,0 I 26,5 I 26,2 I 26,0 I 25,0 I 25,7 I 26,5 I 26,3 I 26,5 I 26,3 I 26,1 I 26,6 I 24,0 Vzorec Material apnen skrilavec I apnenec I tektonska breča | brečast apnenec I apnenec z meljevcem | apnenec z meljevcem | tektoniziran meljevec I apnenec | apnenec | apnenec | apnenec I apnenec | apnenec z meljevcem | apnenec z laporjem I apnenec | apnenec I apnenec I brečast apnenec I apnenec I apnenec I breča z vložki gline I Interval globine E 27,0-27,3 1 45.3-45.5 I 72,1 - 72,4 I 82.4-82.7 I 100,1 -100,4 I со cd" o ю со" o 111,0-111,3 I 126,2-126,6 I 129,8-130,0 I 131,3-131,9 I 133,4-133,7 I со Tf со o tf со 143,0 -143,3 I 146,1 -146,3 I 150,0-150,3 I 150,5-150,9 I cm cm" lo о см" lo co of ю о of ю 174,5-174,9 I 178,5-178,9 I co. о) t- о) Vrtina ozn. V-4 Zap. št. CM со ю со со o) o - cm со lo co co o> о CM cm 312 VUKELIĆ, Ž. ET AL. Zaključek Z izvedenimi raziskavami smo natančneje omejili blok karbonatnih kamnin na površini, s petimi vrtinami in odvzetimi vzorci pa raziskali geološke in geotehnične razmere na obravnavanem prostoru. Preliminarne preiskave kažejo, da so geološko-geotehnične razmere v izdvojenem območju, čigar površina znaša cca 16.000 m2 (230 x 75 m), primerne za izdelavo večjh (do štirih) komor dimenzij premera cca. 24 m in višine cca. 45 m, pod površjem nad globino cca. 150 m v plasteh apnenca, dolomita in breče.[4] Skladišče bi bilo lahko zgrajeno za tlak 15 do 20 MPa. Po podatkih kartiranj in geofizikalnih meritev se različne plasti hitro menjajo med seboj, z geomehanskega stališča pa ni bistvenih razlik med njimi. Območja ne seka nobena večja tektonska cona. Vrednosti RMR ( vrednosti 40 do 50 - Slika 5)[3] uvrščajo ta del v srednji razred po kvaliteti hribine. Za optimalno določitev parametrov PSZP bo potrebno opraviti analizo na podlagi načrtovanja, ki je prikazana na sliki 4. PAKAMETRI HRIBINE LASTNOSTI hribine DIMENZIJE KOMORE У IZRAČUN PARAMETRI SKLADIŠČA Deformacija hribine DEFINIRANJE RAZPOK V BETONSKI OBLOG! Kjer sta: DOLOČITEV OBMOČJA NAJVEČJE DEFORMACIJE HRIBINE POD POVRŠJEM Ж DELOVANJE STR1ŽN1 ODPOR DRSNIH PLOSKEV LASTNOSTI JEKLENE OBLOGE SPREMEMBA TEMPERATUR IZRAČUN Deformacije sten komore V DOLOČITEV OBMOČJA NAJVEČJE DEFORMACIJ E JE KLENE OBLOGE V KOMORI ODPOR NE Aejekin<2*ey ? H 1 r SPREMEMBA PARAMETROV 1 r NADALJNE RAZISKAVE - Ae. jeklo velikost deformacije elastična deformacija DA IZVEDLJIVO DEFINIRANJE MAKS TOLERANC Slika 4. Načrtovanje za PSZP[12] Figure 4. Layout of PSZP project e y 60 65 70 Vrednost RMR Slika 5. Izvedljivost PSZP v odvisnosti od RMR. (Noren, 2006)[3] Figure 5. Layout of geological feasibility Conclusions High Pressure Storage of Gas in Area of Coal Mine Senovo Investigations confirm that the rock mass quality is main factor for determining the maximum size for the cavern and maximum pressure. The rock mass at the proposed site consists of dolomites and limestone and is has been classified as Poor to Fair rock (RMR). It is concluded that a cavern with span of 24 m and height of 45 m is feasible. It is also concluded to consider storage pressure between 15 to 20 MPa. Underground 150 m is possible to construct 4 caverns in area of 230 m x 75 m. Literatura: [1] J. JoHANsoN: High Pressure Storage of Gas in Lined Rock Cavern, 2003, Stockholm, Švedska [2] Ž. VuKELič s soavtorji: Študija možnosti izgradnje visokotlačnega skladišča zemljskega plina v Rudniku Senovo, 2004, Naravoslovnotehniška fakulteta, Oddelek za geotehnologijo in rudarstvo; [3] C. Noren & ..:Underground Storage of Natural Gas in Lined Rock Cavern in Brestanica Area 2006, NCC, Stockholm, Švedska [4] Ž. Sternad s soavtorji: Končno poročilo o geološko- geotehničnih razmerah na področju PSZP Zakov/Senovo, 2006, RGP, Velenje Assessment of surface deformation with simultaneous adjustment with several epochs of leveling networks by using nD relative pedaloid Ocena deformacij-s simultano izravnavo več terminskih izmer z nD relativnim pedaloidom Milivoj Vulić1, Ana Vehovec2 1Faculty of Natural Science and Engineering, University of Ljubljana, Aškerčeva cesta 12, SI-1000 Ljubljana, Slovenia; E-mail: milivoj.vulic@ntf.uni-lj.si 2 DDC svetovanje inženiring, Kotnikova 40, 1000 Ljubljana, Slovenia; E-mail: ana.vehovec@ddc.si Received: November 02, 2006 Accepted: November 14, 2006 Abstract: Relative error hyperellipsoid, 3D relative error pedaloid and 2D relative pedal curve are discussed. Izvleček: V članku govori o 3D relativnem pedaloidu pogreškov in 2D relativni pedali. Key words : Adjustment by parameter variation, nD relative error hyperellipsoid and hyperel- lipsoid, 3D relative error ellipsoid, 2D relative ellipse. Ključne besede: Posredna izravnava, nD relativni hiperelipsoid pogreškov in hiperelipsoid, 3D relativni elipsoid pogreškov, 2D relativni elipsoid. INTRODUCTION Consequence of underground extraction of coal is surface alteration. Negative consequences of mining are reflected above all as ground deformation, field landslides, formation of lakes, climate changes due to alteration of landscape, influence on subterranean waters and thermal springs, seismic effects of subterranean blasting. Ground subsidence is the most intensive above extraction fields but can also be observed on the edge fields. That is the reason for planning local observation networks, by which expanse of deformation can be deter- mined. Observation of networks is important because of closeness of outbuildings and other buildings. With simultaneous adjustment of several epochs of measurements, the field deformation can be determined. Theoretical basis of adjustment by parameter variation in geodetic leveling network Ultimate aim for adjustment of geodetic networks are point coordinates. Definitive 316 Vulić, M., Vehovec, A. or most probable point coordinates can not be obtained by direct mathematical processing of measured quantities (angles, lengths, height differences, etc.), they can be only determined by process of adjustment. This process is possible only if the number of measured data is greater then necessarily needed. In the leveling network adjustment one point with known absolute height should be given (or assumed). This holds for adjustment by parameter (height coordinate) variation. In the adjustment there are three types of quantities: • given quantities (constant values, which don't change by adjustment), • measured quantities, • unknown quantities. By adjustment unknown quantities are determined from given quantities through series of measured quantities on condition that the sum of squares of their residuals is minimal. With observation equation coefficients a., b ,...u., and absolute terms f. Coefficients are partial derivatives of functional relation between given, measured and unknown quantities. Their values depend on configuration and size of network. Absolute terms can be symbolically expressed as f = approximate - measured. Approximate values are computed from approximate coordinates. The adjustment is done considering: vrQ^1v=min or vrPv=min (a) v residuals, Qll correlation matrix of measured quantities, P weight matrix of measured quantities. Observation equations can be written in matrix form: V1 a! h • X /i = «2 b2 . * У + Л a, b, • " Щ t f. (b) Or shortly: v vector of residuals, A design matrix of observation equations, x unknowns vector, f vector of absolute terms. Coefficient matrix of normal equations N reads: v = A-x + f N = A PA \paa\ \pab\ \pba] \pbb] [pwa] \pub\ ■ P = diag[_pj p2 ••• p] (c) \pau\ \pbu\ [P""]j(d) (e) When measurements are of the same accuracy then P = pi, where I is unit matrix. Vector of absolute terms of normal equations n: n = ATPf = WJl \pbf] .[pw/1 = AJpIf = pATf (f) Vector of unknowns is: X = -N_1n = -(АГРА У At Pf = -N"1 ArPf Then vector of residuals can be calculated: v = A-x + f (g) (h) Relative error curve Relative error curve does not depend on the network datum or coordinate origin. nD relative hyperpedaloid and hyperellipsoid Qhypereiupsoid in equation (9) can be written as product of unit matrix I, matrix - hyperellipsoid n,n ... a ' ' ' I - I п,п п,пт n,2n ' I n,n n,n n,n _ Q«ST Q^rV -1 n,n n, n n,n 2n,2 In,In i -.] n,2n n,n T _ t&sr n,n n,n 2n,n Qe Q^ss Q^r QJ&st Q gtyv n,n n,n n,n But also: - hyperellipsoid n,n a A n,n @Asfis Q&sfi,r Q As fir Qfiivfiv or QhfAjt, - Q&sfr Q^sfiv Q^sfiv+ Q&vfiv And after addition: Qà,tA£ = Q.ksfis ~ + Q^vfiv (i) (j) (k) (l) 318 Vulić, M., VEHOVEC, A. 3D relative pedaloid and ellipsoid Figure 1. 3D relative ellipsoid Slika 2. 3D relativni elipsoid The elements of relative error ellipsoid Qempsoid sv are linear combination of matrix Q elements: i ellipsoid SV Qazaz QàZàY Q&Z&X Q&z&y Qay&y Qayax Q&z&x Q&Y&X QàXàX "1 0 0" "1 0 0" 0 1 0 - 0 1 0 0 0 1 0 0 1 Qzszs QzsYs Qzsxs Qzszy QzsYy QzsXy 1 0 0" QzsYs QysXs Qyszv Qysyv Qysxv 0 1 0 Qzsxs Qysxs QXSXS _ QxsZy QxsYr Qxsxy 0 0 1 Qzszv Qyszv Qxszv Qzyzy QzFYy QzyXy =1 0 0" QzsYy Qysyv QxsYy QzyYy Qyvyy Qysxv 0 i 0 Qzsxv Qysxv Qxsxy _ QzyXy Qyyxv QxyXy 0 0 1 (m) After right multiplication: 'ellipsoid SV QbZbZ Qazay QtsZbX Q&z&y Q&z&x Qayay Qayax QAYAX QàXàX "1 0 0" "1 0 0" 0 1 0 - 0 1 0 0 0 1 0 0 1 Qzszs Qzsrs ^Zjlj Qzszy QzsYy QzsXy Qzsys Qysys Qysxs - QrsZy Qysyv Qysxv Qrsxs QxsXs _QxsZv Qysxv Qxsxy QzsZy Qysyv QxsZy özjrZf- QzyYy Q-ZyXy QzsYy QrsZy QxsYy - QzrYy Q-YyYy Qyvxv Qzsxv QrsXy Qxsxy _ QzyXy Q-YyXy QXyXy (n) And after left multiplication: Qazaz Qazay Qazax Qzszs QzsYs Qzsxs Q ellipsoid SV ~ Qazay Qayay Qayax = Qzsys Qws Qysxs _Qazax Qayax Qaxax _ Qzsxs QrsXs QxsXs ^QzsZy QzsYy ^ QysZv Qzyzy QzyYy QzyXy QysZv QzsYy 2Qysyr QysXv ^ QxsYy + QzyYy Qyvyv Qyvxv QxsYy QysXv ^QxsXy Q-ZyXy Qyyxv Qxrxr (o) Matrices in equation (15) are added up (or subtracted) and final value of matrix Qeinpsoidsv is obtained: Q ellivsou Qazaz Qazay Qazax Qazay Qayay Qayax _Qazax Qayax Qaxax ^QzsZy Q-ZyZy ellipsoid SV Qzszs @zsYv QyszV QzyYy @zsYs @zsYv @Yszv QzyYy Qy,n -2a,, +eK •sYs^s ~YSYV QYCXT QycXV QxcYy ',Yy7r + Q: YVXV Özjx^ QzsXy QxsZy ^^ZyXy ^^YeXt! QYVXV ^^XeYv QYvXv -'YgXg *z>YsXf QxcXc XcXi XSYV + Й XvXy (p) 320 VuLIć, M., VEHOVEC, A. 2d relative error pedaloid and ellipse Figure 3. 2D relative pedaloid and ellipsoid Slika 4. 2D relativni pedaloid in elipsoid By the analogy of relative ellipsoid, relative error ellipse is: Q ellipse SV Q&r&Y Qayax Qayax Qaxax Qrsrs QrsXs Qysyv QrsXy ' 1 0 1 0 -1 0" QYsXs Qxsxs QXsYv Qxsxv 0 1 0 1 0 -1 Qysyy QxsYy Qyvyv Qyyxv -1 0 QYsXy Qxsxy Qyvxv Q'XyXy 0 -1 Q&yay Qayax Qayax Qaxax . ' 1 0 Qrsrs Qysyv Qysxs Qxsyv Qysy¥ Qyvyv Qysxv Qyyxy 0 1 Qysxs ~ Qysxr Qxsxs QxsXy QxsYy ~ Qyvxy Qxsxv x у x у -1 0 0 -1 '.SV Qayay Qayax Qayax Qaxax . Qysys ~ 2qysyv + qyfyy Qy.IxS Qysxv Qxsyy Qyvxv QySxS Qxsyf Qysxy Qyvxv ^^ X r X i- ^öxjXn ^^XyXy (q) (r) (s) For given point: Zaključek ' ellipse ST Qay&y Qayax Qay&x Qaxax . summary ^^YyYy QYvXv Ök.A'it ^^XvXV (t) Multi epochs adjustment by parameter variation is simple enough, besides that the points subsidence is calculated directly. In this article nD hyperpedaloid and hyperellipsoid, error ellipse and error ellipsoid were formulated. Ocena deformacij s simultano izravnavo več terminskih izmer z nD relativnim pedaloidom Posredna izravnava več terminskih izmer je dokaj enostavna, poleg tega pa se ugrezke izračunava neposredno. V članku so predstavljeni nD hiperpedaloid in hiperelipsoid, elipsa pogreškov in elipsoid pogreškov. Prikazana je bila njihova izpeljava. Zanje je značilno, da so neodvisni od koordinatnega izhodišča. Their execution was shown. Their characteristic is that they do not depend on coordinate origin. Reference Mihajlovič, К., Vračarić, К., Geodezija III. Građevinski fakultet Beograd, Beograd, 1985. Mihajlovič, К., Vračarić, К., Geodezija I. Građevinski fakultet Beograd, Beograd, 1989. Mihajlovič, К., Geodezija II (2. deo), Naučna knjiga, Beograd, 1978. Mihajlovič, К., Geodezija: Izravnanje geodetskih mreža. Građevinski fakultet Beograd, Beograd, 1992. Todorović, R. Т., Uvod v rudarsko škodo II. Naravoslovnotehniška fakulteta, Oddelek za geotehnologijo in rudarstvo, Ljubljana, 1996. Todorović, R. Т., O relativni elipsi pogreškov. Rudar-sko-metalurški zbornik. 1994: 41, 169-174. Maximum Entropy Theory by Using the Meandering Morphological Investigation Levent Yilmaz Technical University of Istanbul, Hydraulic Division, Civil Engineering Department, Maslak, 80626, Istanbul, Turkey.; E-mail: lyilmaz@itu.edu.tr Received: November 02, 2006 Accepted: November 14, 2006 Abstract: Based on the principle of maximum entropy the primary morphologic equation is derived, and then the equations for hydraulic geometry of longitudinal profile and cross-section are established. For V-shaped cross-sections the relevant morphologic equations which are derived are compared with the existing empirical and semi-empirical formulae. They show good agreement with the prototypes. Key words: Principle of maximum entropy, hydraulic geometry, morphologic equation Introduction Einstein (1950) once pointed out that entropy theory is the first theory for overall science. The principle of maximum entropy has been extensively applied in many domains of natural science. In view of this fact, to apply the principle of maximum entropy is adopted to deal with characteristics of alluvial channels capable of carrying given water and sediment load in meandering boundary layers without causing excessive aggradation and degradation. Width adjustment may take place over a wide range of scales in time and space at meandering channels. In the past engineering analyses of channel width have tended to concentrate on prediction of the equilibrium width for stable channels. Most commonly the regime; extremal hypothesis, and rational (mechanistic) approaches are used. By meandering channels, more recently, attention has switched to channels that are adjusting their morphology either due to natural instability or in response to changes in meandering watershed land use, river regulation, or channel engineering. Characterizing and explaining the time-dependent behavior of width in such channels requires and understanding of the fluvial hydraulics of unstable channels, especially in the near-bank regions. Useful engineering tools are presented, and gaps requiring further field and laboratory research are identified. Finally, this research will consider the mechanics of bank retreat due to flow erosion and deposition at meandering bends, mass failure under gravity, and bank advance due to sedimentation and berm building. It will be demonstrated that, while rapid progress is being made, most existing analyses of bank mechanics are still at the stage of being research tools that are not yet suitable for design applications. Most mathematical models, however, neglect time- dependent channel width adjustments and do not simulate processes of bank erosion or deposition at meandering channels. Although changes in channel depth caused by aggradation or degradation of the river bed can be simulated, changes in width cannot. Meandering channel morphology usually changes with time, and adjustment of both width and depth, in addition to changes in planform, roughness, and other attributes are the rule rather than the exception (Leopold et al., 1964; simon and Thorne, 1996). As a result, the ability to model and predict changes in river morphology and their engineering impacts is limited. The meandering river width adjustments can seriously impact floodplain dwellers, riparian ecosystems, bridge crossings, bank protection works, and other riverside structures, through bank erosion, bank accretion, or bankline abandonment by the active river channel, which are very important for sustainable development of European Mediterranean countries. Considerable research effort has recently been directed towards improving this situation. The objectives of the river width adjustment research were as follows: • Review the current understanding of the fluvial processes and bank mechanics involved in river width adjustment • Evaluate methods (including regime analysis, extremal hypotheses and rational, mechanistic approaches) for predicting equilibrium river width • Assess the present capability to quantify and model width adjustment • Identify current needs to advance both state-of-the-art research and the solution of real world problems faced by practicing engineers To achieve these objectives, river width adjustments may occur due to a wide range of morphological changes and channel responses. Widening can occur by erosion of one or both banks without substantial incision (Everitt, 1968; Burkham, 1972; Hereford, 1984; pizzuto, 1992). Widening in sinuous channels may occur when outer bank retreat, due to toe scouring, exceeds the rate of advance of the opposite bank, due to alternate or point bar growth (Nanson and Hickin, 1983: Pizzuto, 1994) while, in braided rivers, bank erosion by flows deflected around growing braid bars is a primary cause of widening (Leopold and Wolman, 1957; Best and Bristow, 1993; Thorne et al., 1993). In degrading streams, widening often follows incision of the channel when the increased height and steepness of the banks causes them to become unstable. Bank failures can cause very rapid widening under these circumstances (Thorne et al., 1981; Little et al., 1982; Harvey and Watson, 1986; simon, 1989). Widening in coarse-grained, aggrading channels can occur when flow acceleration due to a decreasing cross-sectional area, coupled with current deflection around growing bars, generates bank erosion (simon and Thorne, 1996). Morphological adjustments involving channel narrowing are equally diverse. Rivers may narrow through the formation of in-channel berms, or benches at the margins. Berm/bench growth often occurs when bed levels stage following a period of degradation and can eventually create a new, low-elevation floodplain and establish a narrower, quasi-equilibrium channel (Woodyer, 1968; Harvey and Watson, 1986; simon, 1989; Pizzuto, 1994). Narrowing in sinuous channels occurs when the rate of alternate or point bar growth exceeds the rate of retreat of the cut bank opposite (Nanson and Hickin, 1983; Pizzuto, 1994). Croachment of riparian vegetation into the channel is often satisfied as contributing to the growth, stability, and initiation of berm or bench features (Hadley, 1961; Schümm and Lichty, 1963; Harvey and Watson, 1986; Simon, 1989). In braided channels, narrowing may result when a marginal anabranch in the braided system is abandoned (Schümm and Lichty, 1963). Sediment is deposited in the abandoned channel until it merges into the floodplain. Also, braid bars or islands may become attached to the floodplain, especially following a reduction in the formative discharge. Island tops are already at about floodplain elevation and attached bars are built up to floodplain elevation by sediment deposition on the surface of the bar, often in association with establishment of vegetation. Attached islands and bars may, in time, become part of the floodplain bordering a much narrower, sometimes single-threaded channel (Williams, 1978; Nadler and Schümm, 1981). If the flow regime and sediment supply are quasi-steady over periods of decades, the morphology of the river adjusts to create a metastable, equilibrium form (Schümm and Lichty, 1965). Such rivers are described as being graded or in regime (Mackin, 1948; Leopold and Maddock, 1953; Wolman, 1955; Leopold et al. 1964; Ackers and charlton, 1970a). Although the width of an equilibrium stream may change due to the impact of a large flood or some other extreme event, the stable width is eventually recovered following such perturbations (costa, 1974; Gupta and Fox, 1974; Wolman and Gerson, 1978). Unfortunately, predicting the time-averaged morphology of equilibrium channels remains, despite years of effort, a difficult problem (Ackers, 1992; Ferguson, 1986; Bettess and White, 1987). Many rivers, however, cannot be considered to have equilibrium channels even as an engineering approximation. These rivers display significant morphological changes. Under the assumption that the only information available on a drainage basin is its mean elevation, the connection between entropy and potential energy is explored to analyze drainage basins morphological characteristics. Nearly, 30 years ago, Leopold and Langbein (1962) applied for the first time the concepts of physical entropy to study the behavior of streams. Their application was based on the analogy between heat energy and temperature in a thermodynamic system and potential energy and elevation, respectively, in a stream system. Two ther-modynamic principles were applied. The first principle is that the most probable state of a system is the one of maximum entropy. The second is the principle of minimum entropy production rate. Using these principles, Yang (1971) derived for a stream system the law of average stream fall, and the law of the least rate of energy expenditure . Yang (1971) and others have since applied the latter law to a range of problems in hydraulics. The connection between entropy and potential energy, which these workers so successfully exploited to investigate river engineering, sediment transport, and other problems, was not exploited in hydrology. In this work we pursue this connection to derive relations between entropy and mean elevation for a drainage basin network and to derive relations for the river profiles. Much of the work employing the entropy concepts in hydrology has been with the application of informational entropy. The beginnings of such a work can be traced to Lienhard (1964), who used a statistical mechanical approach to derive a dimensionless unit hydrograph of a drainage basin. It may be visualized that the study of the landscape is the study of constraints imposed by geologic structure, lithology, and history. The way in which some constraints affect the river profile can be evaluated if one considers the profile to approximate its maximum probable condition under a given set of constraints. The most important observations are summarized as below: a) The absence of all constraints leads to no solution. b) The longitudinal profile of a stream system subject only to the constraint of base level is exponential with respect to elevations above base level. c) The profile of a stream subject only to the constraint of length is exponential with respect to stream length which is a logarithmic function with respect to elevation. d) Introduction of the constraint of a partial base level above that of the sea adds a measure of convexity in the profile. Principle of maximum discrete entropy For a discrete variable X, Shannon (1948) defines quantitatively the entropy in terms of probability as: H(X) = -fjP(Xi)LnP(Xi) ,=i (1) where P(Xi) is the probability of a system being in state Xi which is a member of i » (X, i = 1, 2, ...}, and ZjP(X.) = L It has i (=i been proved that H(X) defined by Equation 1 is the only function to satisfy the following three conditions: a) H(X) is the continuous function of P(Xi). b) If and only if all P(Xi) are equal, H (X) attains its maximum value. This conclusion is known as the principle of maximum discrete entropy. c) If the states X and Y are mutually inde -pendent, then H(XY) = H(X)+H(Y). Jaynes (1957) have proved that an equilibrium system under steady constraints tends to maximize its entropy. Based on this statement, the entropy of a river system, having reached its dynamic equilibrium, should approach its maximum value, also the principle of maximum entropy should be valid too for the case of regime rivers. Stream Power Although many formulas for sediment transport have been devised, most can be expressed in terms of stream power as suggested by Bagnold (1960). Power is an important factor in the formulation of the hydraulic geometry of river channels. As explained by Bagnold, the stream power at flows sufficiently great to be effective in shaping the river channel is directly related to the transport of sediment, whose movement is responsible for the channel morphology. Laursen (1958) gives several typical equations for the transport of sediment, based on flume experiments and the average relation shows sediment transport in excess of the point of incipient motion to vary about as (vDS)15 where vDS is the stream power per unit area. In terms of sediment per unit discharge, that is the concentration, C, the several equations average out as C x n (vD)0 5 S15, a result that is consistent with the conclusion reached by Bagnold (1960). There is in addition to be considered the effect of sediment size. Examination of several equations indicates that sediment transport varies inversely as about the 0.8 power of the particle size. There have been several attempts to relate particle size to the friction factor n and by using the Strickler relation that the value of n varies as the 1/6 power of the particle size. It is realized full well that both the sediment transport and the friction factor are influenced by many other factors such as bed form and the cohesive-ness, sorting, and texture of the material. These are the kinds of influences, themselves effects of the river, that prevent a straightforward solution of river morphology. In order to limit the number of variables only the effect of particle size on transport will be considered, as this factor varies systematically along a river from headwater to mouth. Thus, sediment transport concentration is given as C x (vD)05 S15 / n4. The sediment transport per unit discharge in the river system will be recognized as a hydrologic factor that is independent of the hydraulic geometry of a river in dynamic equilibrium. Consequently sediment concentration may be considered constant. Thus, there are three equations: continuity, hydraulic friction, and sediment transport. There are five unknowns. The two remaining equations will be derived from a consideration of the most probable distribution of energy and total energy in the river system. The probability of a given distribution of energy is the product of the exponential functions of the ratio of the given units to the total as pcoe E e E e E ...etc. (1a) The ratios of the units of energy E1, E2, etc., representing the energy in successive reaches along the river sufficiently long to be statistically independent, to the total energy E in the whole length, are E1/E ; E2/E;......En/E. The product of the exponentials of these is the probability of the particular distribution of energy. As previously, the most probable condition is when this joint probability, p, is a maximum and this exists when E1 = E2 = E3 ... = En. Thus energy tends to be equal in each unit length of channel (Leopold and Langbein, 1962). Equable distribution of energy corresponds to a tendency toward uniformity of the hydraulic properties along a river system. Considering the internal energy distribution, uniform distribution of internal energy per unit mass is reached as the velocity and depth tend toward uniformity in the river system. Since the energy is largely expended at the bed equable distribution of energy also requires that stream power per unit of bed area tend toward uniformity. An opposite condition is indicated by Prigogine's (1955) rule of minimization of entropy production which leads to the tendency that the total rate of work, ZQSAQ in the system as a whole be a minimum. Because S x Qz, then ZQ1+z AQ^a minimum. For a given drainage basin this condition is met as z takes on increasingly large negative values. However, there is a physical limit on the value of z, because for any drainage basin the average slope ZSAQ/ZAQ must remain finite. This condition is met only for values of z greater than -1, and therefore z must approach -1 or 1 + z approaches zero. The condition of minimum total work tends to make the profile concave; whereas the condition of uniform distribution of internal energy tends to straighten the profile. Hence, we seek the most probable state. The most probable combination is the one in which the product of the probabilities of deviations from expected values is a maximum. It is unnecessary to evaluate the probability function, provided one can assume normality, as we can then state directly that the product of the separate probabilities is a maximum when their variances are equal. \2 F \ У V ( V У \2 G F V F3 — etc. where F;, F2, F3 represent the several functions. The standard deviations с , с _ с , and m p z cy represent the variability of the several factors as may occur along a river system. Since these values are not known initially, the problem must be solved by iteration (Leopold and Langbein, 1962). Fortunately, the solution is not sensitive to the values of the several standard deviations, so the solution converges rapidly. Therefore, F2 ----1--— Fx G w = 0 2 у (3) for which there are two possible solutions: =0 f \ Fi F2 —-—I--- (J c- CJ cV '1 (4) or / =0 (5) To summarize, we have introduced three statements on the energy distribution: (2) 1 — z-v-»0 2 m + / + z-> 0 (l + z)->0 (6), (7),(8) The absolute values of the standard deviations need not be known, as we can infer their relative values. For example, letting Fj = (1/2)z - y , the standard deviation of Fj is д/(ст,/2)2+ст (9) and F2 = m + f+ z ; aFi - д/а F2=m+f+z (10) Leopold and Maddock (1953) describe and evaluate from field data the hydraulic geometry of river channels by a set of relations as follows: vistjLiHLL- nzdaljifrnj Figure 2. Interpretation of seismic reflection profile KK-02/99. Marked seismic horizons are described in Table 1. Slika 2. Interpretacija refleksijskega seizmičnega profila KK-02/99. Označeni seizmični horizonti so opisani v tabeli 1. KK-03/99 о 1сю0 2000 : »>; 4m» wxw tìhkn 7uoo htìoo ш loouhh l> v.iik,' - глМлЦл (m) Figure 3. Interpretation of seismic reflection profile KK-03/99. Marked seismic horizons are described in Table 1 Slika 3. Interpretacija refleksijskega seizmičnega profila KK-03/99. Označeni seizmični horizonti so opisani v tabeli 1 Gravity data The Krško basin area was investigated so far with gravity method in two detailed surveys, first for hydrocarbons exploration (Urh, 1955) and the second one for underground gas storage in aquifers (Starčević et al., 1989). Both maps showed good correspondence. Since the first survey comprises larger area, we used this map for contouring the maps of seismic horizons. The gravity study performed in 1955 (Urh, 1955) enclosed an area of258 km2 (Figure 1). Altogether 751 points were measured giving an average density of 3 points/km2. Bouguer anomalies were computed using a density of 2.0 g/cm3, derived from laboratory measurements and with Nettleton method. In the Bouguer anomaly map (Figure 1) the shape of the syncline is clearly reflected. Its axis is in WSW-ENE direction. At Drnovo there is a saddle which separates Raka and Globoko depressions. Bouguer anomalies range between +11 and +32 mGal. The minimum values in both depressions are +11 mGal. Two-dimensional gravity modelling was performed along six transversal seismic reflection profiles (Gosar, 2001) acquired in various projects across the Krško basin (Figure 1) including profiles KK-02/99 (Figure 2) and KK-03/99 (Figure 3). Modelled gravity anomalies were compared with observed anomaly profiles extracted from detailed gravity survey (Urh, 1955; Starčević et al., 1989) available in this area. The modelling was proved useful for the interpolation of the shape of the pre-Tertiary bedrock of the basin between seismic profiles. However the possibility to extrapolate the structures interpreted on seismic data to the area outside the grid of reflection seismic profiles is restricted due to the limited extent of the area covered by gravity surveys. Contouring the maps of seismic horizons In reflection profiles recorded in the frame of PHARE project six horizons were identified (Table 1). They include the Mesozoic basement (horizon C) of the Krško basin and five horizons within the Neogene sequence Table 1. Seismic horizons interpreted on profiles recorded in the Krško basin with generalized unit thicknesses (Poljak et al., 1996) and horizon depths drilled in Drn-1/89 borehole (Kranjc et al., 1990; Gosar, 1998) Tabela 1. Seizmični horizonti interpretirani na profilih posnetih v Krški kotlini z generaliziranimi debelinami posameznih enot (Poljak et al., 1996) in globinami horizontov navrtanimi v vrtini Drn-1/89 (Kranjc et al., 1990; Gosar, 1998) Horizon horizont Stage stopnja Thickness debelina (m) Depth in Drn-1 globina v Drn-1 (m) Lithology litologija P1 Pontian Pli2, Q 200 48 sand, gravel, clay pesek, prod, glina P2 A M pontij Pli1 600-700 sandy marl peščen lapor Pannonian panonij M32 150-300 marl lapor Sarmatian sarmatij M31 100 647 sandy marl, marly limestone peščen lapor, laporni apnenec В Badenian badenij M22 350 limestone, sandy marl apnenec, peščen lapor С Ottnangian ottnangij M21 300 969 sand, gravel, conglomerate pesek, prod, konglomerat Kl,2 or T3 marly limestone or dolomite laporni apnenec ali dolomit to capture its internal structure. The most prominent reflection was obtained from near the top of Badenian limestone (horizon B). For contouring the structural maps of seismic horizons we did some trials with computer contouring algorithms (Hamilton & Jones, 1992). These gave quite satisfactory results in case of pre-Tertiary basement (horizon C) (Gosar et al., 2005) which was imaged in all considered profiles, but not so good results in all other horizons inside Neogene sequence (Božiček, 2006). By using computer methods it was also not possible to support interpolation by the use of gravity data. Therefore we decided for manual contouring of maps (Tearpock & Bischke, 2003). We didn't consider the faults in contouring, because the vertical displacements of individual horizons are mostly very small. Time to depth conversion of seismic reflection profiles was based on velocity analyses data. The seismic velocities range from very low values in some parts of the near surface deposits to more than 2500 m/s for the Neogene sequences and 3000 m/s or larger for the Mesozoic. Lateral variations inside individual units are in general small and smooth (Božiček, 2006). For time to depth conversion of old single-fold profiles we used therefore an average velocity function derived from multi-fold reflection profiles. The depth control was available in five boreholes that reached the pre-Tertiary basement (Gosar et al., 2005). The most important is Drn-1 borehole (Kranjc et al., 1990) located near Drnovo in the central part of the basin close to the saddle which separates Raka and Globoko depression. The depths in all structural maps are shown from the elevation 0 m a.s.l., but in the text the depths are considered from the average elevation of the surface which is in the Krško basin 150 m a.s.l.. Seismic horizons The lithostratigraphic description of interpreted seismic horizons (Table 1) is summarized after Persoglia et al. (2000), Poljak et al. (2002), Gosar et al. (2005) and Poljak (2006, personal communication). The deepest horizon mapped was the top of Cretaceous flysch or of Triassic dolomite (horizon C). The lowermost Neogene sequence between horizon C and B represents the Ottnangian sediments transgressively deposited over the Mesozoic basement. These have relatively weak and diffuse seismic signals which is probably caused by their heterogeneous lithological content that consists of gravel, sand, sandy clay and conglomerate. They show several distinct angular discordances with visible onlaping structures that suggests a synsedimentary activity of the depression. In Badenian Lithothamnion limestone (horizon B) was transgressively deposited over Ottnangian sequence. Upwards it transits into sandy and marly limestone, and sandy marl of Badenian to Sarmatian age. They could be distinguished as a separate unit between horizons B and M. This sequence has relative uniform thickness of 200 m, except in the eastern part of the Krško basin (Globoko depression), where it shows a slight increase. This thickness increase is well expressed by overlapping of seismic horizon that corresponds to sandy marl. The next sequence is the Pannonian marl that corresponds to the unit between horizons M and A. Its almost uniform thickness (about 100 m) is slightly increased only in the Glo- Figure 4. Structural map of seismic horizon C (pre-Tertiary basement) Slika 4. Strukturna karta seizmičnega horizonta C (predterciarna podlaga) boko depression. Upwards, this marl transits into sandy marl of Lower Pontian age, which could be distinguished as a separate sequence between horizons A and P2. The Upper Pontian is represented by sand with rare lenses of gravel, except in the Globoko area, where a lateral equivalent consisting of gravel, sand and clay with coal is developed. The beginning of this sequence is recognized as the P2 seismic horizon. The main characteristics of this unit is variable thickness, from 100 m in the western part to up to 500 m in the Globoko depression in the east. The uppermost horizon P1 is related to no clear lithological change within Upper Pontian. Seismic horizon C (pre-Tertiary basement) (Figure 4) The structural map of the pre-Tertiary basement clearly shows the shape of the basin which is elongated in WSW-ENE direction. In the cross direction is the syncline rather symmetric. The average dip of the basement towards the central part is 200. This dip is similar to the average dip of Neogene sediments (Poljak et al., 1996) what is an indication of postsedimentary folding. The eastern Globoko depression has very regular elongated shape and reaches the maximum depth of 2050 m (from the surface) close to the intersection of KK-01/99 and KK-03/99 profiles south of Globoko. The western Raka depression is only partly seen in this map, which is limited to the extent of gravity data. This depression is smaller than the Globoko depression and reaches the maximum depth of 1600 m. Both depressions are separated by a wide saddle at a depth of 1150 m. Seismic horizon B (Badenian-Sarmatian boundary) (Figure 5) This prominent seismic horizon related to Lithothamnion limestone of Badenian age clearly shows a closed syncline in the Figure 5. Structural map of seismic horizon B (inside Badenian) Slika 5. Strukturna karta seizmičnega horizonta B (znotraj badenija) Globoko depression where it reaches the depth of 1650 m. On the other hand in the Raka depression there is no syncline visible at this horizon and the maximum depth is only 650 m. The average thickness of Ot-tnangian and Lower Badenian sediments (between horizons C and B) varies therefore considerably in the Krško basin. In the Globoko depression it is about 300 m, but in the western Raka depression these sediments reach thickness of up to 1000 m. Such a great thickness is anomalous even for the entire Sava folds (Placer, 1998). Thus, the presence of older Tertiary units should not be excluded. Onlaping structures visible in seismic profiles suggests a synsedimentary activity of the depression. Seismic horizon M (Sarmatian-Pannonian boundary) (Figure 6) The seismic horizon M has very similar shape as horizon B. The sequence of sediments in-between has therefore relative uniform thickness of 200 m, except in the Globoko depression, where it shows a slight increase. This thickness increase is well expressed by overlapping of seismic horizon that corresponds to sandy marl that lies over the Lithothamnion limestone. Seismic horizon A (Pannonian-Pontian boundary) (Figure 7) The prominent seismic horizon related to the boundary between Upper Miocene and Lower Pliocene shows again a closed syncline in the Globoko depression with the maximum depth of 950 m. At the saddle between both depressions is its minimum depth 450 m. The thickness of the Pannonian marls is from 200 m in the shallow western part to 400 m in the Globoko depression. Seismic horizon P2 (LowerPontian-Upper Pontian) (Figure 8) The depth of the P2 horizon which separates Lower Pontian sandy marl from Upper Pon- Figure 6. Structural map of seismic horizon M (Sarmatian-Pannonian boundary) Slika 6. Strukturna karta seizmičnega horizonta M (meja sarmatij-panonij) Figure 7. Structural map of seismic horizon A (Pannonian-Pontian boundary) Slika 7. Strukturna karta seizmičnega horizonta A (meja panonij-pontij) tian sand, gravel and clay varies considerably from 250 m in the western part to 650 m in the Globoko depression. The thickness of the Lower Pontian sandy marl is from 200 m in the west to 300 m in Globoko depression. Figure 8. Structural map of seismic horizon P2 (Lower Pontian-Upper Pontian boundary) Slika 8. Strukturna karta seizmičnega horizonta P2 (meja spodnji pontij-zgornji pontij) Figure 9. Structural map of seismic horizon P1 (inside Upper Pontian) Slika 9. Strukturna karta seizmičnega horizonta P1 (znotraj zgornjega pontija) Seismic horizon P1 (inside Upper Pontian) (Figure 9) The uppermost horizon P1 was imaged only along the axis of the syncline at shallow depths from 150 m at the crossing of KK-01/99 and KK-02/99 profiles to 250 m in the Globoko depression. The thickness of the Upper Pontian sand, gravel and clay between horizons P2 and P1 is highly variable, from 100 m in the western part to up to 500 m in the Globoko depression. Conclusions Structural maps of the pre-Tertiary basin and of five horizons inside the sequence of Neogene sediments were prepared based on the interpretation of eleven seismic reflection profiles recorded in three surveys performed in the Krško basin so far. Interpolation of Mesozoic basement between seismic profiles was supported by gravity data. The maps clearly shows rather regular synclinal shape of the Krško basin which is composed of two depressions. The larger Globoko depression in the eastern part is up to 2050 m deep and the smaller Raka depression in the western part is up to 1600 m deep (Figure 4). The thicknesses of some Neogene sequences in-between seismic horizons varies considerably. Most prominent is thickening of the Ottnangian and Lower Badenian sequence between horizons C and B from 300 m in the Globoko depression to up to 1000 m in the Raka depression. On the other hand the thickness of the Upper Pontian sand, gravel and clay increases from 100 m in the western part to up to 500 m in the Globoko depression. There are several indications of synsedimentary folding of the basin, but also some indications of postsedimentary activity. The structural models of seismic horizons will allow additional geophysical and structural-geological interpretations of the area. Together with seismic velocity models they served also as input data for the construction of two-dimensional cross-sections in arbitrary directions for numerical modelling of seismic ground motion in seismic hazard assessment for the location of Krško NPP (Carman, 2006). References Accaino, F., Gosar, A., Millahn, K., Nicolich, R., poljak, M., Rossi, G., zgur, f. (2003): Regional and high-resolution seismic reflection investigations in the Krško Basin (SE Slovenia). Ann. Univ. Sci. Bp. RolandoEötvösNomin., Sect. geol., 35, 116-117. Božiček, B. (2006): Izdelava hitrostnega in strukturnega modela Krške kotline na podlagi refle-ksijskih seizmičnih podatkov. Diplomsko delo, NTF, 54 pp. Carman, M. (2006): Amplification of ground motion at the area of Krško NPP due to local site effects. Ph.D. thesis, University of Nova Gorica, 153 pp. Gosar, A. (1996): Seismic reflection method in structural investigations for assessment of earthquake hazard in the Krško basin. Ph.D. thesis, Univ of Ljubljana, 288 pp. Gosar, A. (1998): Seismic-reflection surveys of the Krško basin structure: Implications for earthquake hazard at the Krško nuclear power plant, SE Slovenia. J. of Appl. Geoph., 39, 131-153. Gosar, A. (2001): Two-dimensional gravity modeling along seismic reflection profiles in the Krško basin. RMZ-Materials and Geoenvironment, 48/3, 473-497. Gosar, A., Komac, M., poljak, M. (2005): Structural model of the pre-Tertiary basement in the Krško basin. Geologija, 48/1, 23-32. (in Slovenian). Hamilton, D. E., Jones, Т. A. (1992): Computer modeling of geological surfaces and volumes. AAPG, 297 pp. Acknowledgments Slovenian administration for nuclear safety is acknowledged for the permission to use seismic reflection data. The authors is grateful to collaborators of the project Geophysical research in the surroundings of the Krško NPP for most recent seismic data. Thanks go to Karl Millahn, Rinaldo Nicolich and Marijan Poljak for many valuable discussions during data interpretation. Thanks go also to Martina Carman and Goran Vižintin for their help in preparation of maps. Kaloper, d. (1984): Krško polje-Brežice, analogna obrada. IGGG, 9 pp. (unpublished report) Kranjc, S., Božović, M., Matoz, Т. (1990): Končno poročilo o geoloških raziskavah na Krškem polju za potrebe podzemnega skladiščenja plina, vrtina Drn-1/89. IGGG, 19 pp. (unpublished report). Persoglia, s., Gosar, A., Millahn, K., Nicolich, R., Nieto, D., Poljak, M., Vesnaver, A., Wardell, N. (2000): Geophysical research in the surroundings of the Krško NPP. Final report. European Commission - PHARE, 68 pp. (unpublished report). Placer, L. (1998): Structural meaning of Sava folds. Geologija, 41, 191-221. Pleničar, M., Premru, u. (1977): Osnovna geološka karta SFRJ 1:100 000, Tolmač za list Novo mesto. Zvezni geološki zavod, 61 pp. (in Slovenian). Poljak, M., Živčić, M. (1995): Tectonics and seismicity of the Krško basin. 1. hrv. geol. kongr., Opatija, 475-479. Poljak, M., Verbič, Т., Gosar, A., Živčić, M., Ribičič, M. (1996): Neotektonske raziskave na območju JE Krško. IGGG, 70 pp. (unpublished report). Poljak, M., Gosar, A. (2001): Strukturna zgradba Krške kotline po podatkih geofizikalnih raziskav v letih 1994-2000. Geološki zbornik, 16, 79-82. (in Slovenian). Poljak, M., Rižnar, I., Verbič, Т. (2002): Geološka zgradba Krške kotline. 1. slov. geol. kongr., Crna na Koroškem, 73-74. Starčevič, M., Stopar, Г., Rihtar, B. (1989): Poročilo o gravimetričnih raziskavah na področju Krškega polja v letu 1989. IGGG, 8 pp. (unpublished report). Šikič, K., Basch, O., Šimunič, A. (1979): Osnovna geološka karta SFRJ 1:100 000, Tumač za list Zagreb. Zvezni geološki zavod, 81 pp. (in Slovenian). Tearpock, D. J., Bischke, Г. E. (2003): Applied subsurface geological mapping with structural methods. Prentice Hall, 822 pp. urh, I. (1955): Poročilo o detajlni gravimetrični izmeri na Krškem polju, 1953-1954. Geološki zavod Ljubljana, 7 pp. (unpublished report). Verbič, Т., Rižnar, I., Poljak, M. Toman, M., Demšar, M. (2000): Quaternary Sediments of the Krško Basin. 2. hrv. geol. kongr., Zbor. rad., Cavtat. 451-457. Uporaba petrofizikalnih preiskav pri oceni obstojnosti in stopnji preperevanja naravnega kamna Use of petrophysical analysis for durability assessment and weathering degree of natural stone Sabina Kramar1, Breda Mirtič2 'Zavod za varstvo kulturne dediščine Slovenije, Restavratorski center, Poljanska 40, 1000 Ljubljana, Slovenija; E-mail: sabina.kramar@rescen.si 2Univerza v Ljubljani, Naravoslovnotehniška fakulteta, Oddelek za geologijo, Aškerčeva 12, 1000 Ljubljana, Slovenija; E-mail: breda.mirtic@guest.arnes.si Received: November 02, 2006 Accepted: November 14, 2006 Izvleček: Poznavanje količine, oblike, velikosti in porazdelitve por v kamnini je ključnega pomena pri študiju propadanja kamnin na objektih oziroma določanja obstojnosti kamnine, ki bo uporabljena za vgradnjo. V pričujočem članku so predstavljene nekatere petrofizikalne metode, s pomočjo katerih lahko ocenimo lastnosti naravnega kamna. Določena je bila celotna in odprta poroznost, koeficient nasičenja, kapilarni dvig, dilatacija zaradi vpijanja vode ter porazdelitev velikosti por kamnine iz kamnoloma Sedovec. Pridobljeni rezultati so pokazali določene razlike v lastnostih obeh litoloških členov, ki sestavljajo kamnino v kamnolomu. Kremenov peščenjak ima večjo poroznost in večji Hirschwaldov koeficient nasičenja ter temu ustrezno nižjo volumsko gostoto kot drugi člen - peščen biosparit. Prav tako so vidne razlike tudi v vrednostih poroznosti med svežo in preperelo kamnino, ki so za slednjo višje. Meritve poroznosti s Hg-porozimetrom so pokazale, da se s stopnjo preperelosti peščenjaka poveča volumen por od 0,052 cm3/g na 0,080 cm3/g. Hirschwaldov koeficient ali koeficient nasičenja obeh členov je manj kot 0,8, zato naj bi bila kamnina malo dovzetna za poškodbe zaradi zmrzali. Abstract:Learning about quantity, shape, size and distribution of pores within the stone is a major significance when studying weathering phenomena or assessing durability of natural building stone. Article deals with petrophysical methods in order to estimate natural stone properties. Bulk and open porosity, saturation coefficient, capillarity, hydric dilatation and pore size distribution of stone from Sedovec quarry has been determined. Results show some differences in properties of both lithological sequences present in the quarry. Siliceous sandstone shows higher values of porosity and Hirschwald coefficient but lower bulk density than sandy biosparite. It is possible to observe the variety in porosity between fresh and deteriorated stone as well. Hg-porosity measurements show an increase of pore volume with augmentation of weathering degree of stone from value of 0.052 cm3/g to 0.080 cm3/g. Value of Hirchwald coefficient or saturation coefficient is less than 0.8 which tells us about low susceptility of studied stone to froze damages. Ključne besede: petrofizikalne preiskave, peščenjak, propadanje, poroznost, kapilarnost, dilatacija Key words: petrophysical analysis, sandstone, degradation, porosity, capillarity, hydric dilatation UVOD Poznavanje količine, oblike, velikosti in porazdelitve por v kamnini je ključnega pomena pri študiju propadanja kamnin na objektih oziroma določanja obstojnosti kamnine, ki bo uporabljena za vgradnjo. Obstojnost kamnine lahko ocenjujemo s petrofizikaln-imi preiskavami. V Sloveniji posamezne petrofizikalne lastnosti kamnine, kot so prostorninska masa, koeficient gostote, poroznost, vpijanje vode, merimo po SIST EN 1925, SIST EN 1936 in po SIST EN 13755 standardih. Z vsemi naštetimi lastnostmi bolj ali manj posredno vrednotimo parametre, ki so povezani s porami v kamnini. Obseg propadanja je močno odvisen od poroznosti, zato je pri ugotavljanju vzrokov poškodb na kamnini in ocenjevanju obstojnosti kamnine pomembno, da poznamo lastnosti pornega sistema. Na podlagi teh lastnosti lahko namreč ocenimo vsebnost in gibanje vode in soli v kamnini, ki spadata med pomembnejše povzročitelje njenega propadanja. Večina lastnosti materiala je odvisna od poroznosti, še posebno način transporta in čas zadrževanja vode v kamnini. Vsaka kamnina vpija, zadržuje in eventualno prepušča določeno količino vode. Količina vode predstavlja vezano, kapilarno in gravitacijsko vodo, ki jo kamnina vpije in zadrži v porah. Voda namreč igra pomembno vlogo pri propadanju kamnin (Winkler, 1997) bodisi z neposrednim delovanjem, npr. pri procesih raztapljanja in precipitacije mineralov, ali pa voda prispeva k ustvarjanju pogojev, kjer nastopajo drugi procesi preperevanja, kot npr. kristalizacija soli, rast mikroorganizmov, slabšanje mehanske trdnosti kamnine (Laurent, 2006). Poroznost materiala j e definirana kot razmeij e med porami materiala in celotnim volumnom poroznega materiala. Strukturo porne mreže določajo poroznost, ki nam podaja volumen por v kamnini ter porazdelitev velikosti por, ki nam podaja način porazdelitve pornega prostora v kamnini v smislu, ali je večje število manjših por ali manjše število večjih por. Slednje močno vpliva na obstojnostne lastnosti kamnine pri učinkih zmrzovanja in kristalizaciji soli (Knöfel et al., 1987, v Bos, 1990). Ločimo mikropore (< 0,01 pm), mezopore (0,01 - 0,1 pm) in makropore (0,1-100 pm) (Amoroso&Fassina, 1983). Pore s premerom, večjim od 1 mm, imenujemo tudi superkapilare, kjer se voda pretaka gravitacijsko (ne zadržujejo vode). Pri kapilarah (0,2 pm - 1 mm) je gibanje vode pod vplivom kapilarnih sil (tu se voda zaradi kapilarnih sil tudi zadrži) pri subka-pilarah (r < 0,2 pm) pa je voda vezana na površino mineralnih delcev z molekulskimi in elektrostatičnimi silami. Pore z radijem r > 0,03 pm ostanejo, z izjemo v izjemnih okoliščinah, nezapolnjene z vodo, zato ne povečujejo nevarnosti nastanka poškodb zaradi zmrzovanja. Zaradi mehanskih pritiskov novih mineralov na njihove stene se večje pore ožijo, manjše pa širijo (Brat-ley, 1998, v Golež, 1999). Kapilare tako v največji meri prispevajo k preperevanju kamnine. Mikroporoznost/makroporoznost je pri Hg-porozimetriji definirana za pore, ki so manjše/večje od 7,5 pm (Goni et al., 1968, v Gal, 2004). Kapilarnost je lastnost materiala, da absorbira tekočine v porah s kapilarnim dvigom. Pogojujeta jo poroznost in porazdelitev velikosti por (Mamillan, 1985 v Bos, 1990). Dilatacija zaradi vpi-janja vode je funkcija strukture in mineralne sestave kamnine. Temu fenomenu sta vzrok dva neodvisna faktorja, in sicer nabrekanje glinenih mineralov in kapilarne sile med mineralnimi zrni. Petrofizikalne preiskave so bile opravljene na peščenjaku srednjemiocenske starosti iz kamnoloma Sedovec, iz katerega je bila uporabljena kamnina za gradnjo pomembnih baročnih spomenikov (Golež, 1999, Vesel&Senegačnik, 2002, Golež et al., 2005). Kamnolom je bil nedavno ponovno odprt zaradi potreb pri restavratorskih posegih na kompleksu cerkve sv. Roka v okolici Šmarja pri Jelšah. Mineraloške spremembe tega peščenjaka, ki so nastale kot posledica preperevanja, so bile že predstavljene (Golež, 1999, Golež et al., 2005, Kramar et al., 2006). V pričujočem članku pa smo določili nekatere petrofizikalne lastnosti omenjenega peščenjaka, na podlagi katerih smo skušali oceniti vpliv mikrostrukture na obstojnost oziroma na propadanje peščenjaka. Eksperimentalni del Izbira vzorcev Preiskovan material je srednjemiocenski peščenjak iz področja Zahodnih Haloz, ki so ga v preteklosti uporabili pri gradnji različnih objektov. V kamnolomu se menjavajo plasti kremenovega peščenjaka s kalcitnim vezivom s plastmi peščenega biosparita. Kamnino od terigenih zrn v glavnem sestavljajo zrna kremena, medtem ko so glinenci, litična zrna in muskovit podrejeni. Med alokemičnimi komponentami močno prevladujejo fosili (predvsem ploščice ehinodermov, foraminifere, preseki iglic iglokožcev, briozoji), nekaj odstotkov pa je glavkonita.Vezivo je v glavnem ka-lcitni cement. Piritni cement je prisoten v sledovih, ki pa je povečini že limonitiziran. Ponekod se kot medzrnski in znotrajzrnski cement pojavlja tudi glavkonit. Nekaj je še mikritne in glinene osnove (Golež, 1999, Vesel&Senegačnik, 2002, Golež et al., 2005, Kramar et al., 2006). Odvzeta sta bila dva vzorca sveže kamnine obeh litoloških členov, sivozelen peščen biosparit (P1) in rjav kremenov peščenjak (P2). Nekatere preiskave so bile opravljene tudi na vzorcu preperele kamnine, da bi lahko opazovali spremembe v vgrajeni kamnini. Slednji je bil odvzet iz dekorativne krogle pete kapele kompleksa cerkve sv. Roka, in sicer na površini (KZ) in v notranjosti (KN) krogle. Uporabljene metode Meritve poroznosti ter kapilarno vpijanje vode so bile merjene po priporočilih RILEM-a (RILEM recomendations - Réunion Internationale des Laboratoires et Experts des Matériaux, Systèmes de Constructions et Ouvrages) (RILEM, 1980). Vzorci sveže Tabela 1. Mineralna sestava vzorcev, določena z optično mikroskopijo v presevni svetlobi (Kramar et al., 2006) Table 1. Mineral composition of used samples, determined by optical microscopy in transmitted light (Kramar et al., 2006) PI P2 KN in KZ kalcitno vezivo, mas.% 35 30 30 nekarb. zrna, mas.% (kremen, litična zrna, muskovit) 25 40 40 kalcitni drobci fosilov 40 30 30 kamnine P1 in P2 so bili oblikovani v kocke 4x4x4 cm, meritve so se izvajale pravokotno na plastnatost. Vrednost celotne poroznosti, ki je dostopna vodi v vakuumu (RILEM I.1) dobimo na podlagi treh meritev. Najprej izmerimo maso suhega vzorca - Ws, ki smo ga sušili v sušilnici na 65±5 °C do konstantne mase. Vzorec nato postavimo v eksikator, iz katerega izčrpamo zrak. Po pretečenem času v eksikator natočimo vodo, iz katere smo predhodno prav tako izčrpali zrak. Po namakanju vzorcev (24 ur) najprej izmerimo maso vzorcev pod vodo - hidrostatična masa W1. Sledi meritev mase vzorcev, prepojenih z vodo na zraku - masa W2. Razlika mas W2-Ws predstavlja volumen por, ki je zapolnjen z vodo - Vv. Iz izmerjene hidrostatične mase - W1 dobimo celotni volumen - Vt vzorcev po formuli: Vt = W2-W1. Celotno poroznost izračunamo po naslednji formuli: Nt = ■ W2-Ws 2 s W2-W1 ■ x 100 [%] (1) Poroznost po 48 urah - N48 (odprta ali efektivna poroznost) (RILEM II. 1) omogoči določiti odprto poroznost, ki je dostopna za vodo v naravnih pogojih (ne v vakuumu) pri atmosferskem tlaku. Gre za sposobnost vpijanja vode. Po sušenju vzorcev do konstantne mase - Ws , so 48 vzorci podvrženi kapilarnemu vpijanju vode za 24 ur, nato pa popolnemu potapljanju v vodo za naslednjih 24 ur. Ko izmerimo maso suhega vzorca - Ws pred namakanjem in maso po namakanju - W48, določimo poroznost kamnine po 48 urah: W -W 48 s N. =-------------x 100 [% 48 (2) W2-W! N48 je vedno manjša ali enaka Nt, ker vedno del mreže por ostane zapolnjen z zrakom. Ta vrednost je primerljiva s prosto poroznostjo oz. z volumnom por, ki jih lahko zapolni voda s kapilarnim dvigom. Razlika Nt-N48 omogoči, da ocenimo zaprto poroznost, ki predstavlja porni volumen, ki ostane zapolnjen z zrakom pri kapilarnem vpijanju vode pri atmosferskem tlaku. Na podlagi teh dveh meritev lahko izračunamo Hirschwaldov koeficient (S48) ali koeficient nasičenja z vodo po 48 urah iz razmerja N48/Nt. Hirschwaldov koeficient predstavlja največjo sposobnost vpijanja vode neke kamnine v naravnih pogojih. Podaja razmerje med praznimi in zapolnjenimi porami, s katerim je definirana odpornost kamnine na zmrzal. Kamnine s koeficientom, ki je večji od 0,8, naj bi bile dovzetne za poškodbe, nastale kot posledica zmrzali, tiste z manjšim koeficientom pa ne (Amoroso&Fassina, 1983, Bourgès, 2006). Na podlagi izmerjenih parametrov je nadalje mogoče izračunati tako volumsko kot skeletno gostoto kamnine (RILEM I.2). Volumska gostota (ang. bulk ali apparent density) predstavlja razmerje med maso in celotnim volumnom vzorca (enačba 3). Skeletna gostota (angl. real density) odgovarja volumnu mase brez por. Je razmerje med maso in volumnom brez por vzorca (enačba 4) in je vedno večja od volumske gostote. W vol W2 - W! x1000 [kg/m3] (3) W vol W - W s 1 x1000 [kg/m3] (4) Kapilarno vpijanje vode (RILEM II.6) omogoči določiti kinetiko absorpcije vode v kamnini v atmosferskih razmerah, ki je pomemben faktor pri ocenjevanju navlaževanja kamnine z vodo. Določeni so bili koeficienti kapilarnega dviga. Vsak vzorec je bil po predhodnem osuševanju do konstante mase (Ws) postavljen pravokotno na plastnatost na blazinico, prepojeno z destilirano vodo, ki je omogočila kapilarno vpijanje vode s spodnje površine. Nato merimo maso vode, ki jo vzorec vpije in višino kapilarnega dviga v odvisnosti od časa, dokler se vpijanje ne stabilizira. Metoda temelji na absorpciji vode skozi osnovno ploskev (ploskev, na kateri stoji vzorec) vzorca kamnine zaradi kapilarnih sil. V principu gre za zamenjavo manj močljivega fluida (zraka) z bolj močljivim fluidom (voda). Možno je definirati dva parametra kapilarnih lastnosti kamnine: • koeficient A, ki nam podaj a spremembo količine absorbirane vode, izražen v gcm-2h-1/2, • koeficient B, ki nam podaja linearno hitrost kapilarnega dviga, podana v cmh-1/2. Dilatacija predstavlja spremembo volumna materiala, ki nastane zaradi ogrevanja in ohlajanja kamnine ali močenja z vodo. V obravnavanem primeru smo merili linearno dilatacijo, ki je odvisna od hidričnih pritiskov, ki nastanejo pri absorpciji vode v vzorcu v odvisnosti od časa in temperature. Dilatacija zaradi vpijanja vode (RILEM II.7) je bila merjena z dilatometrom tipa Capteur LVDT (Low Voltage Transducer) Channel 122 v Laboratoire de Recherche des Monuments Historiques v Franciji. Vzorca, predhodno osušena do konstantne mase, sta bila vstavljena v dilatometer, kjer se je vzorec s kapilarnim dvigom postopoma močil do nasičenosti z vodo. Meritev se je avtomatično izvajala vsaki 2 minuti 48 ur pri stalni temperaturi 25 °C do stabilizacije. Z metodo lahko določimo koeficient linearne dilatacije a (mm/m) = AL/L0, pri čemer je AL sprememba dolžine vzorca med meritvijo, L0 pa začetna dolžina vzorca. Velikost in porazdelitev velikosti por v vzorcih P1 in P2 ter v vzorcih iz krogle KN in KZ smo določili s pomočjo Hg - porozimetra na Kemijskem inštitutu v Ljubljani. Uporabljen je bil inštrument PoreSizer 9310 (Micromer-itic Instrument Co., U.S.A.). Metoda temelji na neomočljivosti živega srebra na stene por kamnine. Ob povečanju pritiska vtiskovanja živega srebra v pore, se radij por, ki je lahko zapolnjen z njim, zmanjša in posledično se celotna količina vtisnjenega Hg poveča. Za izračun rezultatov so bile uporabljene standardne vrednosti parametrov: omočitveni kot med Hg in površino vzorca, 9 = 130° in površinska napetost Hg, у = 0,485 N/m. Gostota Hg pri temperaturi meritve, p = 13.527,6 kg kg/m3. Meritve so bile opravljene na sveže odlomljenih kosih kamnin, približne velikosti 0,5 cm3. Rezultati in razprava Za ocenjevanje mikrostrukture kamnine smo izmerili celotno poroznost - Nt in poroznost po 48 urah - N48 (odprta ali efektivna poroznost) ter kapilarno vpijanje vode. Porazdelitev velikosti por je bila na nekaterih vzorcih določena s Hg-porozimetrom. Prav tako smo testirali dilatacijo kamnine zaradi vpijanja vode. Na ta način smo poskusili oceniti vpliv mikrostrukture na propadanje peščenjaka. Meritev celotne poroznosti, ki je dostopna vodi v vakuumu, je pokazala, da ima peščen biosparit (P1) celotno poroznost Nt = 9,85 %, kremenov peščenjak (P2) pa ima Nt = 13,71 %. Če primerjamo rezultate s kremenovimi peščenjaki iz serije Bundsandstein, ki dosegajo vrednosti med 16,6 % in 24 % (Gal, 2004), vidimo, da ima preiskovan peščenjak dokaj nizke vrednosti. Poroznost N48 peščenega biosparita (P1) je 6,10 %, rjavega pa 10,58 %. Opazimo, da N48 predstavlja približno 2/3 Nt. Pri vzorcu P1 ostane 3,75 % pornega volumna zapolnjenega z zrakom, pri vzorcu P2 pa 3,13 %. Razlike lahko iščemo v znotrajzrnski poroznosti biosparita, saj le ta vsebuje nekatere fosile, ki so vir zaprte poroznosti (briozoji, foraminifere). Hirschwaldov koeficient ali koeficient nasičenja (S48) obeh členov je sicer manj kot 0,8, zato naj bi bila kamnina malo dovzetna za poškodbe zaradi zmrzali. Vendar pa vidimo, da je vrednost vzorca P2 na kritični meji. Dejansko lahko opazujemo, da slednji člen v naravi intenzivneje prepereva. Pri procesu zmrzovanja vode in taljenja ledu v primeru popolnega nasičenja kaže struktura kamnine raztezanje, nastalo zaradi povečanja volumna pri zmrzovanju vode, ki pa po od-tajanju ni reverzibilno. V primeru delnega nasičenja pa zmrzovanje kaže krčenje porozne strukture. Pojav lahko razložimo tako, da se zmrzovanje začne v večjih porah, kjer s tem rast ledu odvzame vodo iz manjših por, kar povzroči krčenje (Everet, 1961 v Snethlage et al., 1996, Stochausen, 1981 v Snethlage et al., 1996). Čeprav je proces pri eksperimentih v laboratorijih reverzibilen, pa lahko domnevamo, da v naravnem okolju po nekaj ciklih ostanejo ireverzibilni premiki, ki povzročajo utrujenost materiala. Rezultati meritev poroznosti s Hg-poroz-imetrom na svežih vzorcih kamnine (tabela 2) potrjujejo rezultate meritev, podanih v tabeli 1. Peščeni biosparit (P1) ima manjšo poroznost od kremenovega peščenjaka (P2). V obeh kamninah je površina por enaka, čeprav povprečni premer por kaže, da ima kremenov peščenjak več večjih por. Volum- Tabela 2. Poroznost svežih vzorcev kamnine, peščenega biosparita (P1) in peščenjaka (P2) Table 2. Results of porosity of samples of fresh stone, sandy biosparite (P1) and sandstone (P2) Oznaka vzorca Celotna poroznost Nt(%) Odprta poroznost N48 (%) Zaprta poroznost Nt -N 48 (%) Hirchwaldov koeficient nasičenja (S48) Volumska gostota (g/cm3) Skeletna gostota (g/cm3) PI 9,85 6,10 3,75 0,62 2,38 2,63 P2 13,71 10, 58 3,13 0,77 2,28 2,64 Tabela 3. Vrednosti preiskave vzorcev z živosrebrno porozimetrijo Table 3. Results of Hg-porosimetry Oznaka vzorca Volumen por (cm3/g) Površina por (m2/g) Povprečni premer po г(цт) Volumska gostota (g/cm3) Skeletna gostota (g/cm3) Pl 0,052 2,8 0,074 2,36 2,69 P2 0,065 2,8 0,093 2,27 2,66 KN (1. meritev) 0,075 3,3 0,092 2,21 2,65 KN (2. meritev) 0,077 2,4 0,127 2,20 2,65 Kz 0,080 2,7 0,120 2,19 2,66 * Specifične površine so izračunane iz izmerjenih premerov por in nj ihove porazdelitve ob predpostavki cilindrične oblike por. ska in skeletna gostota sta v obratnem sorazmerju s poroznostjo (volumnom por). Največjo poroznost ima vzorec kamnine, odvzet na površini krogle, ki je bil tudi najbolj izpostavljen dejavnikom preperevanja po vgradnji. Površina por se v vzorcih iz krogle ni veliko spremenila, pač pa se je znatno povečal povprečni premer por, kar dokazuje, da se v vgrajeni kamnini s časom večajo razpoke in da se slabo vezan material z vodo izpira iz kamnine. Zmanjšanje količine materiala na volumsko enoto se odraža tudi v znižanju volumske gostote. Skeletna gostota se ni značilno spremenila. Rezultati Hg - porozimetra kažejo, da je porazdelitev por v vzorcu P1 bolj nehomogena kot v vzorcu P2, pri vzorcu KN ter KZ pa močno nehomogena. Tabela 4. Porazdelitev velikosti por (%) Table 4. Pore size distribution (%) Količina velikih por (R>5 pm) je v primeru vzorcev sveže kamnine več kot trikrat manjša od tiste v vzorcih preperele kamine. Proces preperevanj a peščenj aka spremlj a povečanj e poroznosti na račun večje količine velikih por. Povečano poroznost praviloma spremlja zmanjšanje mehanske trdnosti kamnine. Krivulji kapilarnega dviga kažeta, da je struktura porozne mreže pri vzorcu P1 malo manj homogena kot v primeru vzorca P2 (slika 1). V začetku je hitrost kapilarnega dviga večja, nato pa vedno manjša. Posebno pri vzorcu P2 opazujemo da je hitrost kapilarnega dviga velika, potem pa se zmanjšuje oziroma se prične stabilizirati. Pri vzorcu P1 lahko opazujemo, da je v prvih petih urah hitrost kapilarnega dviga velika, potem se zelo zmanjša, šele po sedmih dneh se prične stabilizirati. Pl P2 KN (1., 2. meritev) KZ R>5pm 7 10 30,33 34 0,5 pm 0,01 um), vzorca iz krogle, KN in KZ pa 98 % por z R > 0,01um. Razlika je premajhna, da bi lahko iz nje sklepali na hitrost kapilarnega dviga. Glede na povprečni premer por lahko sklepamo, da ima vzorec P2 večje pore, zaradi česar bi morala biti tudi hitrost kapilarnega dviga manjša (manjša vrednost koeficienta B), česar pa meritve Čas (h1/2) Slika 1. Kapilarno vpijanje vode vzorcev sveže kamnine. P1 : peščeni biosparit, P2: kremenov peščenjak Figure 1. Curves of capillary imbibition. P1: sandy biosparite, P2: siliceous sandstone a) b) 0,5 1 1,5 Čas (h 1/2) Slika 2. Določitev kinetičnih parametrov kapilarnega vpijanja vode. a) Koeficient A in b) koeficient B Figure 2. Water absorption coeficients. a) Coefficient A and b) Coefficient B niso potrdile Povprečni premer por očitno ni zadosten dokaz o vrsti in količini posameznih por, ki vplivajo na hitrost kapilarnega dviga. Najvišji nivo kapilarnega dviga, ki ga lahko vidimo v vgrajeni kamnini po nekaj letih, je velikokrat zaznamovan z eflorescenco ali temnim robom, ki zadržuje vlago dalj časa zaradi koncentracije soli na tem nivoju (Bilbija, 1984). Med sušenjem se na meji med conama največje in najmanjše vsebnosti vode razvijejo notranji pritiski. Te napetosti so lahko vzrok za nastanek razpok in oslabitev strukture v coni največjega gradienta vsebnosti vode (Gal, 2004). Raziskava je pokazala, da z uporabljenimi metodami lahko ugotavljamo vrsto in jakost propadanja kamnin, ki so bile uporabljene v kompleksu Sv.Roka. Prav tako lahko z uporabljenimi petrofizikalnimi preiskavami primerjamo obstojnost apnenca in/ali peščenjaka po njuni vgradnji. Dilatacija zaradi vpijanja vode naj bi bil odločujoč parameter pri razumevanju načina obnašanja peščenjaka. Dilatacija je funkcija tako strukture kot mineralne sestave kamnine. Temu fenomenu sta vzrok dva neodvisna faktorja, in sicer nabrekanje mineralov glin in kapilarne sile med mineralnimi zrni. Učinek kapilarnih sil je odvisen od stopnje nasičenja kamnine z vodo. V kamnini, ki je malo nasičena, so meniski omejeni na medzrnske kontakte, njihove kapilarne sile pa delujejo tako, da se kamnina močno skrči. Ko se stopnja nasičenja poveča, se kapilarne sile zmanjšajo, hkrati pa se poviša višina meniska, zato pride do dilatacije. Časa, ki sta potrebna, da dosežemo maksimalno hidrično dilatacijo in kapilarno vpijanje vode, sta ekvivalentna. Dilatacija je torej sorazmerna s stopnjo nasičenja v kamnini. Velja tudi, da je vpijanje vode hitro, kjer je hitrost evaporacije majhna (Gal, 2004). Rezultati so pokazali, da je koeficient dilatacije peščenega biosparita (vzorec P1) 0,098 mm/m ter kremenovega peščenjaka (vzorec P2) 0,589 mm/m. Kremenov peščenjak se razteza kar 6 krat bolj. Iz dobljenih dilatometričnih krivulj vidimo, da dilatacija pri sivozelenemu členu poteka zelo počasi, medtem ko je pri rjavem členu silovita in hitra. Vzroke temu lahko iščemo v naravi zrn (glineni minerali) in poroznosti posameznih členov. Ob intruziji vode pride na začetku vedno do krčenja materiala, kar je razvidno tudi z grafa (slika 3). Vrednosti lahko primerjamo z rezultati, dobljenimi pri drugih raziskovalcih za kremenov peščenjak (Bundsandstein), ki se razteza v intervalu 0,14 - 0,18 mm/m, preperel različek pa 0,46 mm/m (Gal, 2004). Vrednost peščenega biosparita v primerjavi z omenjenim kremen-ovim peščenjakom je dokaj majhna, medtem ko se dilatacija kremenovega peščenjaka približuje vrednostim preperelega kremen-ovega peščenjaka (Bundsandstein) oziroma se razteza celo bolj. Dilatacija mehansko bolj odpornega peščenjaka (P1) je zelo majhna (0,1 mm/m), medtem ko se vrednost me- hansko slabše odpornega (P2) (0,6 mm/m) približuje vrednostim, navedenim v literaturi (Snethlage&Wendler, 1996). Glede na to, da se že sveža kamnina zelo razteza, lahko pričakujemo od preperele kamnine še večji faktor. Znano je, da porozni sistemi odražajo higrično in hidrično raztezanje in krčenje zaradi spreminjajoče se vlažnosti (in vode) kamnine. Z izrazom higrično definiramo omakanje zaradi vlage v plinasti fazi (v intervalu med 0 in 95 % RH), izraz hidrično (namakanje v vodi) pa definira omakanje zaradi vode. Po literaturi je vrednost hidrične dilatacije za peščenjake okoli 0,5 mm/m, lahko pa tudi 5 mm/m v primerih peščenjakov, ki vsebujejo veliko glinene komponente (Snet hlage&Wendler,1996). Prisotnost sadre ali drugih manj topnih produktov preperevanja poveča dilatacijo iz 0,5 na 2 mm/m (Wendler, 1996). Čeprav je dilatacija reverzibilen Čas(h) Slika 3: Dilatacija zaradi vpijanja vode vzorcev sveže kamnine. P1: peščeni biosparit, P2 : kremenov peščenjak, T: temperatura Figure 3: Hydric dilatation of stone. P1: sandy biosparite, P2: siliceous sandstone, T: temperature proces, je treba upoštevati, da lahko pride do utrujenosti materiala zaradi ponavljajočih se ciklusov sušenja in močenja. Utrujenost materiala je na področju proučevanja materiala dobro poznan fenomen, ki nastane zaradi neelastičnega obnašanja kamnine. Pogosto lahko vodi do resnih nepričakovanih poškodb, ki pa jih lahko predvidimo le skozi dolgotrajne preiskave. Preiskave kamnitih objektov, na katerih naj bi potekali restavratorski posegi, so zaradi varovanja objekta vedno narejene na minimalni količini in številu vzorcev. Zato ponovljivost meritev posameznih merjenih parametrov praviloma ni znana. Poleg tega kamnina ni material, ki bi bil vedno homogen čez celoten volumen objekta. Tako smo šele s primerjavo rezultatov vseh izvedenih preiskav lahko ugotavljali obstojnost litoloških členov kamnin, ki jih najdemo v kamnolomu Sedovec. Sklepi Preiskave so pokazale razlike med lastnostmi obeh litoloških členov, in sicer ima rjav laminiran kremenov peščenjak nekoliko slabše obstojnostne lastnosti, saj ima večjo poroznost, vpijanje vode in dilatacijo zaradi vpijanja vode ter je bolj podvržen poškodbam zaradi zmrzovanja. Oba litološka člena po vgradnji tvorita sistem, v katerem se vsak člen razteza drugače, kar lahko privede do nenenakomernih pritiskov na meji med plastmi. Ob absorpciji vode se vsak člen kamnine obnaša drugače, saj je tudi pretok vode v vsakem členu drugačen. Pred- postavljamo, da v kremenovem peščenjaku (dilatacija je 6x večja kot v peščenem biosparitu) verjetno prihaja do zastajanja vode na stiku v peščen biosparit, saj je evapo-racija obratnosorazmerna hitrosti vpijanja vode. Takšna struktura kamnine je namreč ugodna za retencijo vode, ki lahko privede do „mehčanja" strukture ter tudi povečanja nevarnosti razpadanja kamnine pri procesih zmrzovanja. Nasprotno pa je vpijanje vode pri peščenem biosparitu manjše in s tem evaporacija hitrejša. Kamnina ne zadržuje dolgo vlage, kar omejuje prevajanje vode med fazama močenje-sušenje, ki določajo „termo-hidrične" pritiske, ki delujejo na kamnino, vgrajeno na objektu. Oba mehanizma, sušenje in močenje ter zmrzovanje in taljenje ledu, očitno povzročata razmike med zrni in prispevajo k izgubi kohezije kamnine. Rezultati tudi kažejo, da se poroznost kamnine, ki je izpostavljena delovanju okoljskim dejavnikom, poveča. Glede na to, da je voda glavni dejavnik propadanja, je poznavanje pornega sistema, ki ga lahko ocenimo s petrofizikalnimi preiskavami, ključnega pomena pri študiju obstojnostih lastnosti in procesov propadanja kamnin. Pri tem je pomembno tudi natančna določitev parametrov vpijanja vode, ki nam osvetli razumevanje načina gibanja vode v določeni kamnini, saj na podlagi tega lahko sklepamo na posledice vpijanja vode in kristalizacije soli v njih. Vse te zgoraj uporabljene metode v kombinaciji s petrograf-skimi oz. mineraloškimi preiskavami so tako nujne pri proučevanju procesov propadanja naravnega kamna. Summary Use of petrophysical analysis for durability assessment and weathering degree of natural stone Learning about quantity, shape, size and distribution of pores within the stone is a major significance when studying weathering phenomena or assessing durability of natural building stone. Article deals with petrophysical methods in order to estimate natural stone properties. The bulk and open porosity, saturation coefficient, capillarity, hydric dilatation and pore size distribution of stone from Sedovec quarry has been determined. Studied stone is medium coarse siliceous calcium sandstone with transition to sandy biosparite. Sandstone consists mainly of quartz, on the contrary feldspars, lithic grains and muscovite are in minor proportions. Glauconite grains and fragments of different fossils (echinoderma, foraminifera, bivalvia, lithotamnia, briozoi) represent allochemical components of sandstone. Cements consist mainly of calcite, while pyrite and glauconite is present in trace. In attend to estimate stone microstructure the total porosity, porosity of 48 h, capillarity and hydric dilatation were measured. Results show some differences in properties of both lithological sequences present in the quarry. It is possible to observe the variety in porosity between fresh and deteriorated stone as well. Values of total porosity comprised between 9.85 % (sandstone) to 13,71 % (sandy biosparite). Values of porosity 48 h raised from 6.10 % /(sandstone) to 10.58 % (sandy biosparite). These two parameters allow us to determine the Hirchwald coefficient or saturation coefficient which value is in our case less than 0.8 what tells us about low susceptibility of studied stone to froze damages. Pore size distribution was given by Hg-porosimetry, which was carried out on fresh and weathered samples of stone. The main difference of both lithological sequences lies in quantity of large pores, which is higher in sandstone. Regarding fresh and weathered samples, it is obvious that bigger pores contain the sample, which was the most exposed to weathering phenomena. From capillary curves it is possible to obtain the A and B coefficients. Values of A coefficient are 0.043 gcm-2h-1/2 for sandy biosparite and 0.072 gcm-2h-1/2 for sandstone. Values of B coefficient are 0.46 cmh-1/2 for sandy biosparite and 0.65 cmh-1/2 for sandstone. Values of hydric dilatation are 0.46 mm/m in case of sandy biosparite and 0.6 mm/m in case of sandstone. Comparing both litological sequences, sandy biosparite in first of all because of its low porosity show quite better properties regarding susceptibility to weathering. Additionally it has lower velocity of capillarity and hydric dilatation as well and lower susceptibility to froze weathering. Anyway, both - the sandstone and sandy biosparite - form a system, within which each behaves differently. It is to believe that on the sandstone - sandy biosparite are because of different dilatation produced different forces; also they represent a barrier in capillary transfer. As water is considered to be one of the main factors of weathering, studying of pore system with petrophysical analysis means major significance in weathering phenomena of natural stone. Zahvale Avtorici se zahvaljujeva LRMH v Franciji, kjer so nam omogočili opravljanje nekaterih petrofizikalnih preiskav. Posebna zahvala gre tudi prof.dr. Venčeslavu Kavčiču iz kemijskega inštituta za opravljeno Hg-porozimetrijo. VIRI Amoroso, G.G. & Fassina, V., Stone decay and conservation, Atmospheric pollution, cleaning, consolidation and protection. Materials science Monographs.Vol.11. Amsterdam: Elsevier, 1983. 453 str. Bilbija, Nenad. Tehnička petrografija. Svojstva i primene kamene: Univerzitetski udžbenik. Beograd: IRO » Naučna Knjiga«, 1984. 239 str. Bilbija, Nenad in GRIMŠIčAR, Anton. Obstojnost arhitektonskega naravnega kamna iz Slovenije, Geološki zbornik, 1987, št. 8, str.151-160. Bos, K., Weathering and conservation of ferruginous sandstones used as building material in Northern Belgium:The degree of master. Brussel: Faculty of Medecine and Pharmacy of the Vrije Universiteit Brussel, 1990. 220 str. Bourges, A., Holistic Correlation of Physical and Mechanical Properties of Selected Natural Stones for Assessing Durability and Weathering in the Natural Environment, Dissertation der Fakultät für Geowissenschaften der Lunwigs-Maximil-ians- Universität München, 2006, 201p. Gal, G., Influence de la microstructure de différents grès en oevre et de carrière sur leur résistance à l'altération. Aplication aux grès à meules de la cathédrale Notre-Dame de Strasbourg. Travail de diplome. Ecole polytéchnique fédérale de Lausanne. 2004. 52 str. Golež, M., Geološko vrednotenje kamnitih izdelkov iz miocenskihpeščenjakov vzhodne Slovenije: magistrsko delo. Ljubljana: Naravoslovnotehniška fakulteta, Oddelek za geologijo,1999. 122 str. Golež, M., Mirtič, B. & Mladenovič, A., Študij procesov propadanja sljudnato-kremenovega peščenjaka iz Jelšingrada. Materiali in Tehnologije, 2004, let.38, št.1-2, str. 67-70. Golež, M., Mirtič, В., Mladenovič, A. & Kramar, S., Reopening of an abandoned quarry of calcareus sandstone for the restoration of two cultural monuments in Slovenia. 10th Euroseminar on microscopy Applied to Building Materials. Paisley, 2005. Gosselin, c. Le ciment romain. Une source potentielle de sulfates dans la dégradation des pierres de la Cathédrale de Bourges: Travail du Master. Paris: Université Paris 7 et Laboratoire de Recherche des Monuments Historiques, 2005. 81 str. Kramar, S., Mirtič, В., Gunde-cimerman, N., zalar, P.&Golež, M., Vpliv mineralne sestave in mikroorganizmov na propadanje peščenjaka iz kamnoloma Sedovec. Influence of mineral composition and microorganisms on sandstone degradation from Sedovec quarry. RMZ-Materi-als and Geoenvironment. 2006, v tisku Laurent, J.-R, Capillary Water Transfert in Stone Materials: Theoretical and Experimental Aspects. Dostopno na svetovnem spletu: http://www.lthe. hmg. inpg.fr/~laurent/PDF s/Communications/ 98EASCParis.PDF RILEM 25 - PEM, Recommended tests to measure the deterioration of stone and to asses the ef-fectivenes of treatment methods, Bordas-Du-nod.1980 SIST EN 13755:2002 - Preskušanje naravnega kamna - Ugotavljanje vpijanja vode pri atmosferskem tlaku - Natural stone test methods - Determination of water absorption at atmospheric pressure. SIST EN 1925:2000 - Preskušanje naravnega kamna - Ugotavljanje vpijanja vode zaradi kapilarnega dviga - Natural stone test methods - Determination of water absorption coefficient by capillarity. SIST EN 1936:2000 - Preskušanje naravnega kamna - Ugotavljanje prostorninske mase brez por in votlin in prostorninske mase s porami in votlinami ter skupne in odprte poroznosti -Natural stone test method - Determination of real density and apparent density, and of total and open porosity. snethlage, R. In Wendler, E. Moisture Cycles and Sandstone degradation. V Saving Our Architectural Heritage. The Conservation of Historic Stone Structures. Dahlem Workshop Report. Edited by Baer, N.S. in Snethlage, R. Berlin: Freie Universität Berlin, 1996. str.7-24. Vesel, J. & Senegačnik, A., Poročilo o rezultatih predhodnega raziskovanja naravnega kamna -peščenjaka na območju opuščenega kamnoloma Sedovec pri Šmarju pri Jelšah. Ljubljana: Geološki zavod Slovenije, 2002. 10 str., 5 pril. Wendler, E. New materials and approaches for the Conservation of Stone. V Saving Our Architectural Heritage. The Conservation of Historic Stone Structures.Dahlem Workshop Report. Edited by Baer, N.S. in Snethlage, R. Berlin: Freie Universität Berlin, 1996. str.181-198. Winkler, E.M., Stone: Properties, Durability in Man's Environment. Verlag, Berlin Heidelberg New York: Springer, 1997. 313 str. Ladinijske plasti na območju Oble Gorice, osrednja Slovenija Ladinian Beds in the Obla Gorica Area, Central Slovenia Stevo Dozet Geološki zavod Slovenije, Dimičeva 14, 1000 Slovenija; E-mail: stevo.dozet@geo-zs.si Received: September 25, 2006 Accepted: November 14, 2006 Izvleček: Oblo Gorico in njeno okolico grade skitske, anizijske, ladinijske in cordevolske kamnine. Med njimi so najbolj pestro razvite okoli 225 m debele ladinijske plasti, sestavljene iz različnih sedimentnih in vulkanoklastičnih kamnin. Vulkanoklastične kamine in karbonatni sedimenti z roženci ter ladinijskimi fosili leže diskordantno na anizijskem dolomitu, krovnino ladinijskega zaporedja pa predstavlja masivni cordevolski dolomit z ostanki dazikladacej Diplopora annulata Schafhäutl. Ladinijske plasti Oble Gorice so razčlenjene v sedem litostratigrafskih enot. Starost obravnavanega zaporedja je določena z makrofavno. Abstract: Obla Gorica and its surroundings is composed of various Scythian, Anisian, La-dinian and Cordevolian rocks. Among them are most heterogeneously developed about 225 m thick Ladinian beds, composed of different sedimentary and volcaniclastic rocks. Volcaniclastic rocks as well as carbonate sediments with cherts and Ladinian fossils lie discordantly over the Anisian dolomite, while teh hanging wall of the Ladinian rock succession is represented by the massive Cordevolian Dolomite with remains of the Dasicladacea Diplopora annulata Schafhäutl. The Ladinian beds of Obla Gorica are subdivided in seven lithostratigraphic units. The age of the considered stratigraphic sequence is proved by macrofauna. Ključne besede: litostratigrafska razčlenitev, opis enot, fosili in starost, okolje nastanka, ladinij, Posavske gube, osrednja Slovenija Key-words: lithostratigraphic subdivision, description of units, fossils and age, environment, Ladinian, Sava Folds, Central Slovenia. UVOD Na mejnem ozemlju med Posavskimi gubami in Dolenjskim krasom je zaradi dostopnosti terena, odkritosti kamin in neprekinjenega zaporedja plasti za študij ladinijske sedi-mentacije in geoloških dogodkov izbran profil na območju Oble Gorice (slika 1), ki se začne v Obli Gorici, poteka po zahodnem in vzhodnem pobočju Vinjega vrha in se vleče naprej ob makadamski cesti vse do kontakta s cordevolskim dolomitom pod Starim gradom. Prvi detajlnejši opis ladinijskih plasti na območju med Posavskimi gubami in Dolenjskim krasom je podal Germovšek (1955). K ladinijskim plastem je prištel klastične sedimente, temen apnenec, svetle apnence in breče ter dolomit. jeinivrh /Г-ОЫо gonca ,;Jezee gori Л ^ 503 11 JY/ Mišji dol 1.' У ' ^ 59 oi o \ Gradišće \ 1 ^T f •о tj l .Otečvrti \ ai ft ■i \ Л Profil .Temenica ) Cross section ,S Ljubljana rJ-^j 11 " n S ° JL a Jfle Slika 1. Lega raziskanih profilov Figure 1. Location map of the investigated cross- sections Triasni vulkanizem na Dolenjskem je opisal Rakovec (1946). Prišel je do zaključka, da so tufske kamnine v Posavskih gubah produkt istega vulkanizma kot tiste z Bohorja, Orlice in Rudnice. Buser (1976) je detajlno raziskal in opisal profil ladinijskih plasti ob cesti Mišji Dol-Primskovo. Mejno ozemlje med Posavskimi gubami in Dolenjskim krasom je doslej skarti-rano dvakrat. Prvič je bilo kartirano v merilu 1:10 000 v okviru raziskav Dolenjske (Germovšek, 1955), drugič v merilu 1:25 000 v okviru izdelave Osnovne geološke karte SFRJ list Ribnica 1:100 000 (Buser, 1969, 1974). Glavni namen naših detajlnih stratigrafskih raziskav je bil, da v okviru kartiranja za Geološko karto Slovenije 1:50 000 te plasti nadrobno stratimetrijsko raziščemo, kar je omogočilo detajlno litostratigrafsko razčlenitev ladinijske skladovnice v tem delu Slovenije. Geološka zgradba ozemlja Geološka zgradba obravnavanega ozemlja je najbolj razvidna iz stratimetrijskega profila Preska (Obla Gorica)-Mišji Dol-Slivnikov vrh, ki na dolžini več kilometrov preseka grödenske, spodnjetraisne (skitske), anizij-ske, ladinijske in cordevolske plasti s skupno debelino okoli 2000 metrov (slika 1). Od grödenskih plasti seka profil le nj ihov 100 m debel zgornji del, ki je sestavljen iz sivka-stordečega, svetlordečega in zmerno rdečega srednjezrnatega do zrnatega, pogosto kon-glomeratičnega in redkeje drobnozrnatega močno sljudnatega kremenovega peščenjaka. V kompleksu rdečih grödenskih klastitov ni nikjer sledov plastnatosti, zato sklepamo, da gre za masivne kopenske sedimente v katerih se pogosto, zlasti pa na površini razpok opaža tirkiznomodra in modrikastosiva oksidna prevleka. Rdeči grödenski sedimenti prehajajo ponekod v bočni in navpični smeri v zelenkastosive klastite s podobno mineralno sestavo. Nedaleč od tod je na Ježnem vrhu ohranjena celotna skladovnica grödenskih klastitov, ki je debela okoli 400 m, med rdečimi drobno-zrnatimi klastiti pa se pojavljajo tudi vložki kompaktnega, plastnatega, debelozrnatega kremenovega peščenjaka in konglomerata. Nad grödenskimi plastmi ni v profilu niti temnih zgornjepermskih karbonatnih kamnin niti sedimentov dveh bazalnih skitskih členov, zato smatramo, da je v zgornjem permu in najspodnjejšem skitu obstajalo v tem delu Slovenije kopno, na katerem pa ni bilo akumulacije kopenskih sedimentov. Gre za občutno stratigrafsko vrzel in odsotnost sedimentacije, saj se skitske plasti pričenjajo šele s klastiti seiskega člena, ki sestoji iz zaporedja sivkastordečega lističastega in tankoploščastega sljudnatega peščenjaka sivkastorumenega in sivkastooranžnega peščenega (sljudnatega) laporovca. Srednjemu skitu bi lahko prišteli pisane sljudnate klastite z okoli 4 m debelim vložkom ploščastega in plastnatega (3-40 cm), drobno in sre-dnjezrnatega, sivkastordečega oosparitnega apnenca s preseki gastropodov /Holopella gracilior Schauroth/ ter 2,5 m debelih vložkov sivkastorumenega, kompaktnega, ploščastega in plastnatega (3 cm do 30 cm), močno peščenega apnenčevega laporovca. Zgornji (campilski) del skitskega zaporedja sedimentov sestoji iz treh členov. Spodaj je okoli 50 m debel klastični člen, ki sestoji iz tankoploščastih pisanih peščenjakov, peščenih laporovcev in skrilavih glinavcev, navzgor sledi okoli 125 m debel člen ru-menkastosivega, ploščastega in plastnatega peščenega (sljudnega) dolomita z interkala-cijami peščenega dolomitnega laporovca. Na vrhu skitskega zaporedja je okoli 50 m debel člen črnega plastnatega apnenca, ki je deloma gomoljast in vsebuje krinoidne ostanke. Nepopolna skitska skladovnica (manjkata najspodnjejša člena) je debela okoli 300 m. Konkordantno na črnem plastnatem gomo-ljastem skitskem apnencu leži plastnat, zelo svetlosiv, drobno do srednjezrnat anizijski dolomit. Skladovnica anizij skega dolomita j e debela okoli 75 m. Tudi v tem profilu je meja med anizijskim dolomitom in ladinijskimi plastmi precej pokrita. Kontakt grödenskih in skitskih plasti je razkrit tudi ob cesti severozahodno od Oble Gorice. Diskordantno na opekastorde-čem, lističastem in zelo tankoploščastem (1-2 cm) rdečem skrilavem glinavcu z vložki zelenkasto in modrikastosivega ter rjavkastordečega, ploščastega (2-10 cm), drobnozrnatega peščenjaka leži okoli 45 m debelo zaporedje pretežno ploščastega (2-5 cm), tu in tam plastnatega (10-29 cm), izredno močno peščenega (sljudnatega), sivega, olivnosivega, temnoolivnosivega, oranžnorumenega, sivkastorumenega, ope-kastordečega, mestoma rdečega, tirkiznomo-drega in zelenosivega dolomita, peščenega laporovca in peščenjaka. Na lezikah plasti opazujemo močno nakopičenje sljude. Nad opisanim klastično-karbonatnim zaporedjem leži okoli 15 m debela skladovnica rumenkastosivega do oranžno rumenega, močno peščenega (sljudnatega) dolomita. Po litološki sestavi pripada opisano zaporedje pisanih sedimentov nad kontaktom z grö-denskimi plastmi seiskemu členu werfen-a v Dolomitih. Nad opisanimi seiskimi platmi leži okoli 65 m debelo zaporedje izredno pisanih klastičnih in dolomitnih plasti, ki sestoji iz dveh približno enako debelih delov. V spodnjem delu prevladujejo izredno pisane klastične kamnine nad peščenim dolomitom, v zgornjem delu pa prevladujejo manj pisani ploščasti in tankoplastnati peščeni dolomiti. Te plasti lahko primerjamo s horizontom Andraz I v Tirolskih Dolomitih. Nad horizontom Andraz I je pri Kuhlju (Obla Gorica) in severno od tod razvit tudi gastro-podni oolitni člen, ki je debel okoli 50 m. V njem prevladujejo pisani skitski klastiti, kjer razlikujemo dva dela. V spodnjem delu so v pisanih klastitih plasti in leče srednje temnosivega do temnosivega, ploščastega in plastnatega (30-50 cm), mikritnega in drobno zrnatega apnenca z redkimi ooidi, v ope-kasto in sivkastordečem, tankoploščastem (1-5 cm) kremenovem peščenjaku in skri-lavem glinavcu pa so dokaj pogostne plasti in leče sivkastordečega oolitnega dolomita z Fe ooidi. Zgornji del skitskih sedimentov je odsekan s prelomom, tako da mejijo tukaj spodnjeskitske plasti z anizijskim dolomitom prelomno. Na svetlosivem do srednje temnosivem, plastnatem (15-40 cm), drobnozrnatem anizijskem dolomitu ležita v profilu Obla Gorica-Mišji Dol rumenkasto olivnozelen pelitni tuf in temno olivnozelen ter olivnosiv zelo drobnozrnat do srednjezrnat tuf z vložki črnega mikritnega apnenca in debelozrna-tega kalkarenita. Navzgor sledi 11 m debel apnenčev člen, ki v spodnjem delu sestoji iz sivkastočrnega in črnega, plastnatega (15-30 cm), mikritnega in drobnozrnatega apnenca, v zgornjem delu pa iz sivkastočr-nega in rumenkastosivega apnenčevega lapo-rovca s prehodi v laporni apnenec. V vrhnjem delu vsebuje apnenec roženec in tanjše vložke tufov. Nad apnenci s tufi leži okoli 100 m debela skladovnica srednje sivega, ploščastega (2-10 cm) in plastnatega drobnozrnatega dolomita z gomolji in tankimi vmesnimi plastmi črnega roženca. Nato se v debelini 65 m menjavajo črni laporni apnenec, apnenčev laporovec in redkeje kalkarenit z več tankimi vložki tufa in tufskega pešče- njaka. Preostali del ladinijske skladovnice izpolnjuje bledorumenkastosiv, ploščast (5-15 cm) drobnozrnat dolomit z gomolji roženca. Izmerjena debelina ladinijskega litološkega zaporedja znaša 400 m. Kon-kordantno na ladinijskih plasteh leži precej debela skladovnica srednjesivega in svetlosi-vega do belega, masivnega, debelozrnatega, luknjičastega cordevolskega dolomita, tu in tam z ostanki in preseki diplopor. V tektonskem pogledu leži obravnavano ozemlje v mejnem prostoru med severno ležečimi Posavskimi gubami in južno ležečimi mezozojskimi grudami. Med njimi doslej ni ugotovlj ena izrazitej ša tektonska meja. Da je stik Posavskih gub in Dolenj skega krasa bolj ali manj normalen so menili Kossmat (1913), Germovšek (1955), Rakovec (1956) in Buser (1974), tektonske elemente tega stika pa so ugotovili sedlar et al. (1948), Buser (1965) in Dozet (1966, 1985). V tektonskem pogledu prevladujejo na obravnavanem ozemlju strukture s smerjo severozahod-jugovzhod. Material in metode Podatki, uporabljeni v tem članku, so pridobljeni pri regionalnem geološkem karti-ranju za izdelavo Geološke karte Slovenije 1:50 000, kjer je prevladovala metoda profiliranja. Najnovejši, predvsem sedimentološki podatki so dobljeni pri stratimetrijskem profiliranju. Istočasno s stratimetrijskim profiliranjem je potekalo vzorčevanje kamnin za različne laboratorijske preiskave. Karbonatne kamnine so določene po Folkovi (1959) in Dunham-ovì (1962), klastične pa po Pettijohn-ovì klasifikaciji. STAROST AGE ZAPOREDJE SUCCESSION ^ w з: U. — 2 -J ьс ш L CÜ = ш * О t- L 1 TOST R A T 1 G R A F S K E ENOT E LITHOSTRATIGRAPHIC UNITS о <л LO < ÙL i— г < ш щш (71) m Sve t losi vi masivni deheiozrnati dolomit Light grey massive coarse-grained dolomite m ода оо ш 7 tn (N Plastna ti in ploščasti zrnati apnenec Bedded and piaty grainea limestone з: < •ж. о < _i —> z О < _i z 7 1 6 О m Л А л v v ^ Л А А v V v V AAA Tufi z vložki tufskih peščenjakov Tuffs with interbeds of tuff sandstones 5 m CN — 1 — i- Temni laporni apnenec in laporovec Dark marly limestone and marls tone \ — 1 — 1 4 in YJ1Ч4, fc V'-oV-. С" ft SP i Гr ir VA j- чай! Pf \ Wik b i лЯ^ч?- - ач я * ■ •■■ -- (b) Cone probe-С (19 K/s) J jf _ (c) Cone probe - B (38 K/s) Figure 10. Microstructure of the sample Vz.l (d) Cone probe - A (176 K/s) (basic alloy) As a result two diagrams are showing the relationship between largeness of the micro-structural constituents and the cooling rate for the range of 6 K/s to 176 K/s. Figures 12 and 13 are showing relationship between largeness of the crystals and of the eutectic silicon particles as the function of the cooling rate. We also calculated the physical model for the grain size reduction and the eutectic silicon particle reduction as the function of the cooling rate. Fitted exponential curves are also shown on Figures 13 and 14. Equations and parameters of the fitted curves are collected in Table 7. (с) Cone probe - В (3 8 K/s) (d) Cone probe - A ( 176 K/s) Figure 11. Microstructure of the specimen Vz.4 (grain refined with B, modified with Sr) Table 7. Equations and parameters of the calculated physical models Grain size Model R2 У0 Al ti Vz.l y=A 1 exp(-x/t 1 )+y0 0.99999 307.41226 +/-4.21092 4080.72927 +/-40.58991 7.55081 +/-0.09232 Vz.4 0.97071 97.10749 +/-0.47917 142.64657 +/-4.3781 17.38183 +/-0.63481 Vz.ll 0.97292 262.866 +/-1.97866 1079.5082 +/-24.6731 14.59254 +/-0.35247 Particle length Vz.l y=A 1 exp(-x/t 1 )+y0 0.99044 5.52465 +/-0.61155 34.20882 +/-19.42654 5.17144 +/-2.49776 Vz.4 0.99994 0.52289 +/-0.02266 8.84548 +/-0.13965 9.12575 +/-0.20775 Vz.ll 0.86737 0.54676 +/-0.20373 0.89092 +/-0.37989 25.70911 +/-22.90963 У MP ' (a) Quick cup (6.3 K/s) ФГ7ЧК - I (b) Cone probe - C (19 K/s) (c) Cone probe - B (38 K/s) (d) Cone probe - A (176 K/s) Figure 12. Microstructure of the specimen Vz.11 (grain refined with Ti, modified with Na) 2200-, 20001800 1600-1 „ 1400- li 1200-dx (4) Second, desire field function U(x) is obtained by equation (5): U(x)=G(x)+A-x + B (5) where A and B are the random constants. A and B are defined according to boundary conditions of field function U(x), that are: U»^ U(l)=uL. U(x) = G(x) + \uL-uO-G(L) + G(0)]- -+uO- G( 0) L (6) If upon the temperature field acts external force F(x), it cause "echo", so the temperature field U(x) has obtained form. Function U(x) is echo function of temperature field equilibrium (the balance of thermal state of the system). Function U(x) is produced through the balance of external force F(x) and force that causes changes in U(x) field only when x variable is changing time independent. This working regime is characteristics for many heat aggregates. While keeping the temperature during the time, thermal aggregate is in state of equilibrium. This state became stationary after some time of oven heating. To determine real U(x) function all before mentioned parameters must be defined: the length L, then U0 and UL. The most important step is determination of parameter K- giving its value followed by dimension and unit. H function influence on equilibrium state might be negligible since it is assumed that U is time independent function, so it can be written that H = 1. Function F(x) depends of heat conducted into the kiln. The discretization above aimed to enable easier computer modeling and calculation, but also form step approximation of function F(x). Sense of the discretization is to replace all functions F(tTxyz) which depend of time, spatial coordinates and place inside the kiln, with set of discrete values. Equilibrium function Starting point is assumption that there exists a relationship between final product characteristics and factors such as: temperature field regime inside the kiln, refractory linings, carriage and product. This relationship is very complex by its nature (affected by nature of factors by itself as well as by number of different influencing factors). Manufacturing process essentially is a mechanism that realizes mentioned relationships in a way that each product is accompanied by values of certain campaign for which temperature equivalent of heating the chamber, that is actually fuel consumption per 1 kg of product, can be measured. Temperature equilibrium data has been presented by measured heating curve (Figure 1) from which values of the coordinates x and Table 1. Measuring points and temperatures in the chamber Tj (0.0 m, 30 °C) T2 (3.9 m, 65 °C) T3 (19.9 m, 400 °C) T4 (25.1 m, 440 °C) T5 (30.8 m, 460 °C) T6 (36.9 m, 600 °C) T7 (43.2 m, 710 °C) T8 (45.8 m, 780 °C) T9 (48.4 m, 825 UC) Tio (51.0 m, 860 UC) T„ (53.6 m, 865 °C) T12 (56.2 m, 865 UC) T13 (58.8 m, 865"C) T14 (61.4 m, 865 °C) T15 (71.6 m, 800 °C) T16 (82.6 m, 710 "C) T17 (88.0 m, 660 UC) Tig (118,0 m, 60 UC) Abbreviated as Ti (de^, ve^), i = 1,2,...,18. 900 N 4 n 50 60 70 Furnace lenght [m] Figure 1. Measured heating curve y were taken: x (distance from starting point or enter into the chamber) and y (temperature equivalent of the external force). From the diagram in Figure 1, 18 points with their coordinates have been taken and separately presented in Table 1. External force function is unknown since the K value is also unknown. But values of the temperature given in Figure 1 might be taken as a thermal energy equivalent used to obtained force F. Then, external force is presented as: v[i] if x = deb] Fx=\ i = 1,2,3.. 0 if X Ф de^ (7) Desired function G, for which is G =F,, (x) (x) (x) or X G'(x)= fF(x)dx de\i] . Integration results in: (8) G, = Vi for der, < x . povzetek (Times New Roman, 12) A short summary of the contents in Slovene (up to 400 characters) can be written by the author(s) or will be provided by the referee or by the Editorial Board. TEMPLATE for Slovenian Authors The title of the manuscript should be written in bold letters (Times New Roman, 14, Center) Naslov članka (Times New Roman, 14, Center) Name Surname1, .... , & Name Surnamex (Times New Roman, 12, Center) Ime Priimek1, ..., Ime Priimekx (Times New Roman, 12, Center) xFaculty of ... , University of ... , Address..., Country; e-mail: ... (Times New Roman, 12, Center) XFakulteta..., Univerza., Naslov., Država; e-mail: ... (Times New Roman, 12, Center) THE LENGTH OF ORIGINAL SCIENTIFIC PAPER SHOULD NOT EXCEED TWENTY (20, INCLUDING FIGURES AND TABLES) PAGES (OPTIMAL 7 TO 15), SHORT PAPER FOUR (4) AND OTHER TWO (2) WITHOUT TEXT FLOWING BY GRAPHICS AND TABLES. DOLŽINA IZVIRNEGA ZNANSTVENEGA ČLANKA NE SME PRESEGATI DVAJSET (20, VKLJUČNO S SLIKAMI IN TABELAMI), STROKOVNEGA ČLANKA ŠTIRI (4) IN OSTALIH PRISPEVKOV DVE (2) STRANI. Abstract(Times New Roman, Bold/Normal, 11): The text of the abstract is placed here. The abstract should be concise and should present the aim of the work, essential results and conclusion. It should be typed in font size 11, single-spaced. Except for the first line, the text should be indented from the left margin by 10 mm. The length should not exceed fifteen (15) lines (10 are recommended). Izvleček(TNR, B/N, 11): Kratek izvleček namena članka ter ključnih rezultatov in ugotovitev. Razen prve vrstice naj bo tekst zamaknjen z levega roba za 10 mm. Dolžina naj ne presega petnajst (15) vrstic (10 je priporočeno). Key words: a list of up to 5 key words (3 to 5) that will be useful for indexing or searching. Use the same styling as for abstract. Ključne besede: seznam največ 5 ključnih besed (3-5) za pomoč pri indeksiranju ali iskanju. Uporabite enako obliko kot za izvleček. Introduction - Uvod (Times New Roman, Bold, 12) Two lines below the keywords begin the introduction. Use Times New Roman, font size 12, Justify alignment. All captions of text and tables as well as the text in graphics must be prepared in English and Slovenian language. Dve vrstici pod ključnimi besedami se začne Uvod. Uporabite pisavo Times New Roman, velikost črk 12, z obojestransko poravnavo. Naslovi slik in tabel (vključno z besedilom v slikah) morajo biti pripravljeni v slovenskem in angleškem jeziku. There are two (2) admissible methods of citing references - obstajata dve sprejemljivi metodi navajanja referenc: 1. by stating the first author and the year of publication of the reference in the parenthesis at the appropriate place in the text and arranging the reference list in the alphabetic order of first authors; e.g.: 1. z navedbo prvega avtorja in letnice objave reference v oklepaju na ustreznem mestu v tekstu in z ureditvijo seznama referenc po abecednem zaporedju prvih avtorjev; npr.: "Detailed information about geohistorical development of this zone can be found in: Antonijević (1957), Grubić (1962), ..." "... the method was described previously (Hoefs, 1996)" 2. by consecutive Arabic numerals in square brackets, superscripted at the appropriate place in the text and arranging the reference list at the end of the text in the like manner; e.g.: 2. z zaporednimi arabskimi številkami v oglatih oklepajih na ustreznem mestu v tekstu in z ureditvijo seznama referenc v številčnem zaporedju navajanja; npr.; "... while the portal was made in Zope[3] environment." Results and discussion - Rezultati in razprava (Times New Roman, Bold, 12) Tables, figures, pictures, and schemes should be incorporated (inserted, not pasted) in the text at the appropriate place and should fit on one page. Break larger schemes and tables into smaller parts to prevent extending over more than one page. Tabele, sheme in slike je potrebno vnesti (z ukazom Insert, ne Paste) v tekst na ustreznem mestu. Večje sheme in tabele je potrebno ločiti na manjše dele, da ne presegajo ene strani. Conclusions - sklepi (Times New Roman, Bold, 12) This paragraph summarizes the results and draws conclusions. Povzetek rezultatov in zaključki. Acknowledgements - Zahvale (Times New Roman, Bold, 12, Center - optional) This work was supported by the ****. References - Viri (Times New Roman, Bold, 12) Regardless of the method used, in the reference list, the styling, punctuation and capitalization should conform to the following: Ne glede na uporabljeno metodo pri seznamu citiranih referenc upoštevajte naslednjo obliko: FIRST OPTION - in alphabetical order (v abecednem zaporedju) Casati, P., Jadoul, F., Nicora, A., Marinelli, M., Fantini-Sestini, N. & Fois, E. (1981): Geologia della Valle del'Anisici e dei gruppi M. Popera - Tre Cime di Lavaredo (Dolomiti Orientali). Riv. Ital. Paleont.; Vol. 87, No. 3, pp. 391-400, Milano. Folk, R. L. (1959): Practical petrographic classification of limestones. Amer. Ass. Petrol. Geol. Bull.; Vol. 43, No. 1, pp. 1-38, Tulsa. SECOND OPTION - in numerical order (v numeričnem zaporedju) [1] Trček, B. (2001): Solute transport monitoring in the unsaturated zone of the karst aquifer by natural tracers. Ph.D. Thesis. Ljubljana: University of Ljubljana 2001; 125 p. [2] Higashitani, K., Iseri, H., Okuhara, K., Hatade, S. (1995): Magnetic Effects on Zeta Potential and Diffusivity of Nonmagnetic Particles. Journal of Colloid and Interface Science 172, pp. 383-388. Citing the Internet site: CASREACT-Chemical reactions database [online]. Chemical Abstracts Service, 2000, updated 2.2.2000 [cited 3.2.2000]. Accessible on Internet:. Citiranje internetne strani: CASREACT-Chemical reactions database [online]. Chemical Abstracts Service, 2000, obnovljeno 2.2.2000 [citirano 3.2.2000]. Dostopno na svetovnem spletu: . Povzetek - Summary (Times New Roman, 12) An extended summary of the contents in Slovene (from one page to approximately 1/3 of the original article length). Razširjeni povzetek vsebine prispevka v Angleščini (od ene strani do približno 1/3 dolžine izvirnega članka). Citation and indexing of RMZ-Materials and geoenvironment (Število citatov in indeksiranja člankov RMZ-M&G) (prepared by Pezdič, J. - from search done by Sercelj, M., CTK Ljubljana Citation index according to Web of Science 1970 -2006: 110 papers have 165 citations (4x before 1998, max. 49x in 2004) (110 člankov je bilo citirano 165 krat - 4x pred 1998; največ 49x v letu 2004)) No. of indexing of RMZ- M&G in singular Databases (Število indeksiranih člankov iz RMZ- M&G v posameznih bazah) Database Name Total before 1998 1 Civil Engineering Abstracts 773 770 3 2 CA SEARCH® - Chemical Abstracts® (1967- present) 760 475 285 3 : Inside Conferences 313 237 76 4 : Materials Business File 253 253 5 METADEX® 164 38 126 6 : ANTE: Abstracts in New Technologies and Engineering 158 158 7 : GeoRef 154 30 124 8 Aluminium Industry Abstracts 36 9 27 9 PASCAL 30 30 10 : Energy Science and Technology 27 27 11 TEME - Technology and Management 27 27 12 : Ei Compendex® 13 13 13 : CSA Aerospace & High Technology Database 12 12 14 : Computer and Information Systems 10 10 15 : Mechanical & Transportation Engineering Abstracts 8 7 16 Engineered Materials Abstracts® 3 3 17 Corrosion Abstracts 3 3 18 : Analytical Abstracts 1 1 19 FLUIDEX 1 1 20 Solid State and Superconductivity Abstracts 1 1 21 : Electronics and Communications Abstracts 1 1 2748 2004 744 - Total No. of Databases (število vseh baz): 21 - No. of new bases in RMZ-M&G after 1998 (število novih baz v RMZ-M&G po 1998): 7 - Total No. of indexing (število indeksov skupaj): 2748 - No. of indexing after 1998 (število indeksov po 1998): 2004 - No. of indexing between 1970-1998 (število indeksov med 1970-1998): 744 RMZ - Materials and Geoenvironment RMZ-M&G, Vol. 53, No. 3_pp. 285-417(2006) Contents Time - Dependent Processes in Rocks Likar, J., Vesel, G., Dervarič, E., Jeromel, G. 285 Možnost izvedbe visokotlačnega podzemnega skladišča zemeljskega plina na območju Rudnika Senovo Vukelić, Ž., Sternad, Ž., Vukadin, V., Čadež, F., Hudej, M., Pečovnik, I. 303 Assessment of surface deformation with simultaneous adjustment with several epochs of leveling networks by using nD relative pedaloid Vulić, M., Vehovec, A. 315 Maximum Entropy Theory by Using the Meandering Morphological Investigation Yilmaz, L. 323 Structural maps of seismic horizons in the Krško basin Gosar, A., Božiček, В. 339 Uporaba petrofizikalnih preiskav pri oceni obstojnosti in stopnji preperevanja naravnega kamna Kramar, S., Mirtič, B. 353 Ladinijske plasti na območju Oble Gorice, osrednja Slovenija Dozet, S. 367 Effect of the grain refinement, modification and the cooling rate on microstructure of the AlSilOMg alloy Petrič, M., Medved, J., Mrvar, P. 385 Temperature field analysis of tunnel kiln for brick production Duraković, J., Delalić, S. 403 Autor's Index, Vol. 53, No. 3 409 Instructions to Authors 410 Template 412 Number of paper indexing in diferent bases 417 http://www.rmz-mg.com