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With the development of computer technology, artificial neural networks are becoming increasingly useful in the field of engineering geology and geotechnics. With artificial neural networks, the geomechanical properties of rocks or their behaviour could be predicted under different stress conditions. Slope failures or underground excavations in rocks mostly occurred through joints, which are essential for the stability of geotechnical structures. This is why the peak shear strength of a rock joint is the most important parameter for a rock mass stability. Testing of the shear characteristics of joints is often time consuming and suitable specimens for testing are difficult to obtain during the research phase. The roughness of the joint surface, tensile strength and vertical load have a great influence on the peak shear strength of the rock joint. In the presented paper, the surface roughness of joints was measured with a photogrammetric scanner, and the peak shear strength was determined by the Robertson direct shear test. Based on six input characteristics of the rock joints, the artificial neural network, using a backpropagation learning algorithm, successfully learned to predict the peak shear strength of the rock joint. The trained artificial neural network predicted the peak shear strength for similar lithological and geological conditions with average estimation error of 6%. The results of the calculation with artificial neural networks were compared with the Grasselli experimental model, which showed a higher error in comparison with the artificial neural network model. Nevronske mreže postajajo z razvojem računalniške tehnologije vedno bolj uporabne tudi na področju inženirske geologije in geotehnike. Z nevronskimi mrežami lahko na osnovi večjega števila podatkov napovemo geomehanske lastnosti kamnine ali njihovo obnašanje v različnih napetostnih pogojih. Porušitve brežin ali podzemnih prostorov v kamninskem masivu se večinoma pojavijo po razpokah, zato so strižne lastnosti v razpokah ali prelomih bistvene za stabilnost geotehničnih objektov. Preiskave strižnih lastnosti so večinoma dolgotrajne, prav tako pa je pri vrtanju v fazi raziskav težko pridobiti primerne vzorce. Velik vpliv na velikost vrhunske strižne trdnosti ima hrapavost površine razpoke, natezna trdnost in vertikalna obremenitev. V predstavljenem članku je hrapavost površine razpok izmerjena s fotogravimetričnim skenerjem, vrhunska strižna trdnost pa je določena z Robertsonovo direktno strižno preiskavo. Na osnovi šestih vhodni karakteristik razpok in kamnine ter izmerjene strižne trdnosti z Robertsonovo preiskavo, lahko z naučeno nevronsko mrežo uspešno napovemo vrhunsko strižno trdnost po razpoki. Tako naučena nevronska mreža lahko dovolj natančno napove vrhunsko strižno trdnost za podobne litološke razmere in geološke pogoje, z upoštevanjem dokaj nizke napake, to je 6%. Rezultate izračuna z nevronskimi mrežami smo primerjali z eksperimentalnim modelom, ki je v primerjavi z nevronskimi mrežami pokazal višjo napako napovedi vrhunske strižne trdnosti.

According to recent literature in the field of sustainability, the circular economy (CE) appears to be a thriving opportunity for creating new businesses, although less attention has been paid to the form in which its principles fit into a comprehensive framework that enables companies to design it in a practical way. This paper presents the methodology that has been adopted to pave the way to a coherent reference framework for circular business model innovation and its outstanding design and implementation, taking into consideration the entire value and supply chain. A unique analysis of recent innovations in circular economy models is provided herein, together with an exhaustive analysis of those elements that enable or hinder their implementation. The main interactions among all those critical elements influencing how organisations innovate and operate cooperatively within a CE ecosystem are also evaluated. In addition, a study of five industrial cases in the pulp and paper industry allowed searching for industrial insights and empirical evidence of the relevance of those elements, including observation, document analysis, and interviews. Lastly, the main outcomes of this research are illustrated using the CE reference framework designed when applied to the aforementioned industrial cases, and relevant insights into future improvements are also provided. Nasl. z nasl. zaslona. Opis vira z dne: 1. 10. 2021. Št. članka 10285. Abstract. Bibliografija: str. 15-16.

Geotechnical structures in rock masses such as tunnels, underground caverns, dam foundations and rock slopes often have problems with a jointed rock mass. The shear behaviour of a jointed rock mass depends on the mechanical behaviour of the discontinuities in that particular rock mass. If we want to understand the mechanical behaviour of a jointed rock mass, it is necessary to study the deformation and strength of a single joint. One of the primary objectives of this work is to improve the understanding of the frictional behaviour of rough rock joints under shear loads with regard to the roughness of the joint surface. The main problem is how to measure and quantify the roughness of the surface joint and connect the morphological parameters into a shear strength criterion. Until now, several criteria have been developed; however, all of them used large rock samples (20×10×10 cm). It is often not possible to get large samples, especially when the rock is under a few meters thick layer of soil. In this case, samples of rock can only be acquired with investigation borehole drilling, which means that the samples of rock are small and of different shapes. The paper presents the modifid criterion that is suitable for calculating the peak shear stress of small samples.

27th ARRB Conference 2016, Linking people, places and opportunities, MELBOURNE, AUSTRALIE, 16-/11/2016 - 18/11/2016; The European Commission has launched, within the Horizon 2020 (H2020) Programme, several initiatives associated with the development of cross-modal transport infrastructure. Three European H2020 Coordination and Support Actions, namely the REFINET, FOX and USE-iT projects, have been established to support this work. The aim of the FOX (Forever Open Infrastructure across all transport modes) project is to develop a highly efficient and effective cross-modal research and development (R&D) environment and culture which meets the demanding requirements of the transport and connectivity of people and goods. The FOX project involves a network of researchers and practitioners from the different modes. It sets the agenda for the further improvement of cross-modal research development innovation, as well as the demonstration and implementation of the results.The overall objectives of the first phase of the project are to: undertake a review of international practice associated with construction, maintenance, recycling and re-use and inspection; and identify state-of-the-art research and best practice methods across road, rail, airfields and waterways. Based on the results of this research, phase two of the project involves the identification of the most appropriate methods which could be applied on a cross-modal basis. This involves the identification of new technologies (concepts/methods/materials) with promising properties, and the optimisation of these methods across the four themes in terms of their cross-modal benefits and application. The final phase of the project is to develop a road map for future research and development and guidelines regarding how these initiatives could be implemented across each mode. In this sense, the FOX project seeks to find common methods across all transport modes. This paper describes the outcomes of the first of the three deliverables completed to date and the key next steps of the FOX project.

The railway infrastructure is a very important component of the world%s total transportation network. Investment in its construction and maintenance is significant on a global scale. Previously published life cycle assessment (LCA) studies performed on road and rail systems very seldom included infrastructures in detail, mainly choosing to focus on vehicle manufacturing and fuel consumption. This article presents results from an environmental study for railway steel bridge materials for the demonstration case of the Buna Bridge in Croatia. The goal of these analyses was to compare two different types of remediation works for railway bridges with different materials and construction types. In the first part, the environmental impact of the classical concrete bridge construction was calculated, whereas in the second one, an alternative new solution, namely, the strengthening of the old steel bridge with ultra-high-performance fibre-reinforced concrete (UHPFRC) deck, was studied. The results of the LCA show that the new solution with UHPFRC deck gives much better environmental performance. Up to now, results of LCA of railway open lines, railway bridges and tunnels have been published, but detailed analyses of the new solution with UHPFRC deck above the old bridge have not previously been performed. Železniška infrastruktura je zelo pomemben del celo - tnega transportnega omrežja. Gradnja in vzdrževanje prog tudi v svetovnem merilu predstavlja velik strošek. Dosedanje LCA študije (analiza življenjskega cikla), iz - vedene na cestnih in železniških omrežjih zelo redko vključujejo podrobno analizo infrastrukture, večino - ma se osredotočijo na porabo goriva za proizvodnjo in pogon vozil. V prispevku so predstavljeni rezultati iz okoljske študije za uporabljene materiale železniškega mostu %Buna most% na Hrvaškem. Cilj te analize je bil primerjati dve različni metodi sanacije starega mostu s poudarkom na uporabi različnega materiala in za različne tipe konstrukcij. V prvem delu je bil izračunan vpliv na okolje za klasično betonsko konstrukcijo mo - stu, medtem ko je v drugem prikazan izračun za novo alternativno rešitve sanacije mostu; ojačanje starega jeklenega mostu s UHPFRC (mikroarmiran beton zelo visokih zmogljivosti) ploščo. Rezultati LCA kažejo, da ima nova rešitev z UHPFRC ploščo veliko manjši vpliv na okolje kot klasična betonska konstrukcija. Do sedaj objavljene LCA študije so se večinoma osredotočale na analize gradnje in sanacije odprtih železniških prog, železniških mostov in predorov. Za novo alternativno metoda, sanacije železniškega mostu z UHPFRC ploščo, okoljska LCA analiza do sedaj še ni bila objavljena.

Anticipated climate changes in Europe over the next 100 years were estimated using two different scenarios of carbon dioxide emissions and two computational approaches. The principal manifestations of climate change within the European region are predicted to be a rise in temperature, an increase in rainfall intensity in most areas and a decrease in freeze–thaw cycling. The impacts of such possible climate changes were then estimated for pavements and the pavement-related infrastructure. It should be noted that the life cycle of pavements is much shorter than the time span over which climate change might have a statistically significant influence on pavement performance. Several analytical and numerical analyses were performed in order to simulate the effect of future climate change, taking into account the fact that the effect of these changes on pavements structures will depend on local conditions. In particular, temperature and rainfall increase will be a challenge for asphalts, as both rutting and stripping of asphalt layers can be expected. In countries where roads are presently frequently frozen in winter, the length of this period of freezing will be reduced. For this reason, many thin and unsealed pavements will need to be upgraded if high bearing capacity is to be maintained. In coastal and low-lying areas raised water tables may occur due to areas where flood waters may collect, or due to raised sea levels. For most applications, appropriate responses to these changes in pavement performance will be achievable through the use of new design criteria with regard to temperature and the return period of storm flows. More attention needs to be paid to drainage systems, which should be self-cleaning and easy to inspect.

U radu su prikazana iskustva u korištenju različitih tipova dilatometara pri ispitivanju stijena. Daju se teorijske osnove i preporuke za korištenje odgovarajućeg tipa dilatometra ovisno o deformabilnosti stijenske mase. Naglašava se problematika interpretacije izmjerenih veličina i pravilnog korištenja rezultata mjerenja. Prikazuju se i ocjenjuju rezultati mjerenja različitim tipovima dilatometra na više lokacija u Hrvatskoj, Sloveniji i Iranu. Uspostavljena je korelacija dilatometarskog modula i modula iz velikih in situ ispitivanja vapnenca.

Predstavljen je primer izgradnje podzemnih prostorov kamnoloma Hotavlje. Podani so rezultati numerične zvezne analize in numerične analize ločenih elementov. Ugotovljeno je, da je zvezna analiza primerna za preverjanje globalne stabilnosti podzemnega prostora, z nadaljno analizo pa je mogoče dobiti natančnejše izračune o stabilnosti blokov v okolici izkopa. Za preverjanje stabilnosti posameznih blokov in podpornega sistema za posamezen blok, pa je še vedbo bolj natančna blokovna analiza. Prvi pogoj za zanesljivo stabilnostno analizo je dovolj vhodnih podatkov o geomehanskih lastnostih hribine. Za to so potrebne terenske in laboratorijske preiskave in geotehničnemeritve. Na podlagi večjega števila izdelanih stabilnostnih analiz je bila za podzemne prostore kamnoloma Hotavlje ugotovljena največja širina podzemnih prostorov 12 m.

V magistrski nalogi Geološki pogoji plitvega in globokega temeljenja na heterogenem umetnem nasipu so predstavljene terenske in laboratorijske preiskave za pridobitev geomehanskih lastnosti zemljin, na podlagi katerih so bili izvedeni izračuni nosilnosti temeljev za bodoči objekt na območju osrednje Slovenije. Terenske preiskave so zajemale spremljavo vrtanja ter popis 6 vrtin do globine 15 m, merjenje z žepnim penetrometrom, žepno krilno sondo ter standardno penetracijsko preiskavo. Na terenu so bili odvzeti vzorci iz različnih globin vrtin za laboratorijske preiskave. Z laboratorijskimi preiskavami smo pridobili podatke o fizikalno – mehanskih lastnostih zemljin, kot so gostota, konsistenčne meje, stisljivost in trdnost. Na podlagi vseh pridobljenih podatkov so bili izvedeni izračuni nosilnosti pilotov in temeljne plošče po različnih metodah ter primerjava le-teh. The master’s thesis entitled Geological conditions of shallow and deep foundations on a heterogeneous artificial embankment presents field and laboratory research to obtain geomechanical properties of earths, based on which calculations of the load-capacity of foundations for the future object in central Slovenia were performed. The field research included monitoring of the drilling and recording of 6 boreholes to a depth of 15 m and measuring with a pocket penetrometer and a pocket vane probe and a standard penetration examination. In the field, samples from different depths of the boreholes were taken for laboratory examinations. With the laboratory examinations we obtained data about the physical and mechanical properties of earths, like density, consistency limits, compressibility and strength. Based on all the obtained data, we calculated the load-capacity of piles and the foundation plate using different methods and compared them.

V inženirski geologiji lahko heterogene kamnine zaradi svojega anizotropnega obnašanja predstavljajo precejšnje izzive pri geotehničnem projektiranju. Prav zato je zelo pomembno razumevanje geomehanskega obnašanja heterogenih kamnin, ki je odvisno od deleža posameznih kamnin in strukturnih značilnosti, kar pomeni, da moramo pri njihovi klasifikaciji v sklopu inženirsko-geološkega popisa čim bolj natančno določiti delež posameznih litoloških enot in značilnosti diskontinuitet. Takšna kamnina je tudi fliš, za katero je značilno ciklično menjavanje drobnozrnatih in debelozrnatih klastičnih kamnin, ponekod z vmesnimi plastmi apnenca, breče, konglomerata ali kalkarenita. Ravno pri flišnih kamninah je zelo vidna odvisnost stabilnosti od strukturnih značilnosti, ki so odvisne od lastnosti diskontinuitet. V magistrski nalogi sem preverila stabilnost izkopnih brežin v flišnih kamninah s poudarkom na določitvi parametrov diskontinuitet ter njihovo vključitev v analize. Terensko delo z detajlnim inženirsko-geološkim popisom izdankov fliša sem izvedla v JZ delu Slovenije v bližini Črnega Kala, na območju gradnje 2. tira Divača–Koper, s poudarkom na uveljavljenih ročnih metodah določitve lastnosti diskontinuitet ter odvzema vzorcev za laboratorijske preiskave. S pridobljenimi podatki sem fliš klasificirala po uveljavljenih sistemih klasifikacij, in sicer RMR (RMR faktor za oceno hribine) in GSI (geološki indeks trdnosti), geomehanske parametre pa sem povzela iz predhodnih raziskav v podobnih hribinah. Izvedla sem tudi analitično analizo z računalniškim programom RocPlane ter numerično analizo s programom Slide2 in primerjala primernost uporabe programov pri stabilnostnih analizah v flišnih kamninah. Heterogeneous rocks in engineering geology can pose significant challenges in geotechnical design due to their anisotropic behavior. Therefore, it is very important to understand the geomechanical behavior of heterogeneous rocks, which depends on the proportion of individual rocks and structural characteristics, which means that the classification of such rocks in the engineering-geological inventory the proportion of individual lithological units and discontinuities must be determined as accurately as possible. Such rock is also flysch, which is characterized by cyclic alternation of fine-grained and coarse-grained clastic rocks, sometimes with intermediate layers of limestone, breccia, conglomerate or calcarenite. The dependence of stability on structural characteristics, which depend on the properties of discontinuities, is very visible in flysch. In my master 's thesis, I checked the stability of excavated slopes in flysch with an emphasis on determining the discontinuity parameters and their inclusion in the analyzes. Field work with a detailed engineering-geological inventory of flysch outcrops was in the SW part of Slovenia, near Črni Kal, in the area of construction of 2nd rail Divača–Koper, with emphasis on established manual methods for determining discontinuity properties and taking samples for laboratory tests. With the obtained data I classified flysch according to established classification systems, namely RMR (Rock Mass Rating) and GSI (Geological Strength Index), geomechanical parameters were taken from previous research in similar rocks. I also performed analytical analysis with the program RocPlane, numerical analysis with the program Slide2 and compared the suitability of using the programs in stability analyzes in flysch.

Z novejšimi raziskavami je bilo dokazano, da na strižno trdnost kamninske razpoke vpliva njena celotna geometrija. Napredek tehnologije v zaznavanju topografije nam omogoča natančen opis geometrije v treh dimenzijah. Za opis površine razpoke so bili uvedeni 3D površinski parametri hrapavosti in tako nadomestili pomanjkljiv 2D opis razpok z enim profilom. Na osnovi večjega števila direktnih strižnih preiskav so bili izpeljani novi empirični kriteriji za izračun vrhunske strižne trdnosti po razpoki, ki v svojem zapisu vključujejo površinske parametre hrapavosti. V magistrski nalogi sem preverila primernost do sedaj znanih kriterijev za napoved vrhunske strižne trdnosti. V ta namen je bilo z Robertsonovim strižnim aparatom preiskanih 24 vzorcev različnih litologij, katerim so se izračunali tudi 3D površinski parametri hrapavosti razpok. Yang-ov kriterij in Tang-ov kriterij sem modificirala glede na rezultate analiziranih strižnih preiskav. Dobljene rezultate preiskav sem primerjala tudi s podatki preiskav iz literature, ki so bile izvedene v veliki strižni celici. Izmed vseh analiziranih kriterijev Yang-ov kriterij najbolj točno napove vrhunsko strižno trdnost na vzorcih iz literature, njegova modifikacija pa na preiskanih vzorcih. Podobno oceno točnosti ima pri podatkih iz literature tudi Grasselli-jev kriterij medtem, ko na rezultatih preiskanih vzorcev ne doseže dovolj nizke ocene napake. Ker so bili kriteriji osnovani na podlagi preiskav vzorcev večjih dimenzij v direktni strižni celici, sklepamo, da je potrebno kriterije za uporabo na manjših vzorcih, preiskanih z Robertsonovim strižnim aparatom, modificirati. Modificirana kriterija, predlagana v magistrski nalogi, sta podala najbolj točno in sprejemljivo oceno vrhunske strižne trdnosti v primerjavi z ostalimi kriteriji. Izvedla sem tudi parametrično analizo, s katero sem ugotavljala vpliv posameznega parametra na kriterije. Izmed vseh površinskih parametrov ima parameter hrapavosti C največji vpliv. Recent results of research have shown that the shear strength of a rock joint is affected by its overall geometry. Technology advancement in the perception of the topography enables us to give a precise description of the geometry in three dimensions. 3D surface roughness parameters were introduced to describe the surface of the joints, thus replacing the inadequate 2D description along one profile of a rock joint. Based on a large number of direct shear tests, new empirical criterions for the calculation of peak shear strength of a rock joint were derived. New criterions take into account 3D surface roughness parameters. In my master's thesis, we examined these known criterions for predicting peak shear strength. For this purpose, 24 samples of different lithologies were investigated with Robertson's shear apparatus. We also calculated 3D surface roughness parameters to use them in criterions. Yang's and Tang's criterions were modified according to the results of the analyzed shear tests. Obtained results of the investigations were also compared with data from literature where investigations were carried out in the large shear cell. Among all the analyzed criteria, Yang's criterion most accurately predicts peak shear strength of a rock joint on the samples from the literature. Modified Youns's criterion also gives the best results on the investigated samples. Accuracy assessment of the Grasselli's criterion is similar to Young's on literature samples, while the results of the investigated samples do not reach a sufficiently low error rate. Since the criterions were based on the investigation of bigger samples in the direct shear cell, it is concluded that the modification of criterions for the use on small samples studied by Robertson shear apparatus is required. The modified criterions gave more accurate and acceptable assessment of peak shear strength of a rock joint compared to unmodified criterions. I also carried out a parametric analysis to determine the influence of an individual parameter on the criterions. Among all 3D surface roughness parameters, parameter C has the greatest impact.

Prve ideje o izgradnji visokotlačnega skladišča zemeljskega plina na Reštanju oz. pod vzpetino Gradec v krajevni skupnosti Senovo segajo v leto 2004. Ob visokotlačnem podzemnem skladišču najprej pomislimo na trdno hribino, ki je npr. iz granitnih kamnin, vendar pa so raziskave na Švedskem pokazale, da je visokotlačna skladišča zemeljskega plina možno zgraditi tudi v karbonatnih kamninah. V diplomskem delu sem se osredotočila na vpliv višine nadkritja in delovnega tlaka, ki se vzpostavi ob izkopu ter polnitvi visokotlačnega skladišča zemeljskega plina na pomike in napetostno stanje v hribini ter na luščenje kamnine. Izdelala sem osemnajst geomehanskih modelov. Geomehanski modeli so bili izdelani z metodo robnih elementov z numeričnim programom Examine2D podjetja Rocscience. Vsak geomehanski model je kombinacija različnih višin nadkritij in obremenitev oz. delovnih tlakov. Za vsak model so bile opravljene podrobne analize, v katerih sem sledila spremembam pomikov in napetosti ter stabilnosti izkopa glede na kriterij luščenja v štirih kontrolnih točkah. Poleg opravljenih analiz so v diplomskem delu podrobno opisane geografske in geološke značilnosti predvidenega območja gradnje ter postopek inženirsko-geološkega popisa hribine in določitve hribinskih tipov. Med drugim so predstavljene tudi tri uporabljene klasifikacije hribin: RQD (Rock Quality Designation index), RMR (Rock Mass Rating) in GSI (geološki trdnostni indeks). Analiza modelov je pokazala, da se z višino nadkritja pomiki v hribini bistveno ne izboljšujejo oz. ta nima velikega vpliva na rezultate. Delovni tlak ima veliko večji vpliv, in sicer tako pozitiven kot negativen. Glede na rezultate ugotavljam, da je optimalni delovni tlak v mejah med 10 in 15 MPa. The idea of building a high-pressure underground storage of natural gas in Reštanj bellow the Gradec Hill, Senovo community (southeastern Slovenia), was initiated in 2004. Normally, high-pressure underground storages of natural gas are built in strong rocks like granite. But research in Sweden has shown that it is also possible to build a high-pressure underground storage in carbonate rocks. In my diploma thesis I simulated the effect of different heights of overburden and of working pressures produced by filling of the planned storage in Senovo. I have modelled displacements, stress field, and have evaluated spalling criteria. Eighteen geomechanical models were designed using boundary element method with numerical program Examine2D (Rocscience). Each produced model uses a different combination of overburden height and working pressure. For each model I evaluated the displacements, stress field, and the stability of the excavation according to the spalling criterion in four checkpoints. In addition to the analyses carried out in this thesis, detailed geographical and geological characteristics of the planned building area are described along with the processes of engineering geological description of rock masses and determination of rock types. Also, three classifications used in rocks are presented. These standard classifications are: RQD (Rock Quality Designation Index), RMR (Rock Mass Rating) and GSI (Geological Strength Index). Analysis results show that the overburden height does not significantly influence the rock response. Much larger is the imapct of working pressure, both in a negative and positive way. From the modeling results the optimal working pressure is in the range from 10 MPa to 15 MPa.

Diplomsko delo obravnava laboratorijske preiskave nesaturiranih zemljin s poudarkom preiskovanja fenomena sukcije. Sukcija je merilo za energijo, ki v strukturo zemljine privlači vodo ali jo tam zadržuje. V geotehniki sukcijo merimo s pomočjo različnih metod, kjer nas zanimajo predvsem vrednosti matrične sukcije. Meritve sukcije so bile opravljene v Geomehanskem laboratoriju Zavoda za gradbeništvo Slovenije, kjer smo sukcijo merili s pomočjo Bishop-Wesley dvostenske triosne celice in s potenciometrom, z namenom določanja retencijske krivulje v fazi sušenja vzorcev. Preiskave so potekale na dveh različnih materialih: trdnih peščeno meljnih zemljinah in na vzorcih mulja. Trdni melji so pri gradnji v slovenskem prostoru prisotni izjemoma in zato v geotehničnem smislu deležni obsežnejših preiskav. Veliko skrb predstavlja spreminjanje trdnostnih lastnosti v odvisnosti od zasičenosti, saj so v primeru, ko so izpostavljeni močenju ali obremenitvam, podvrženi porušitvam (kolapsu). Na izbranih vzorcih so bile najprej izvedene osnovne klasifikacijske preiskave: sejalne analize, meritve vlažnosti in gostote. Poleg merjenja sukcije v fazi sušenja smo meritve sukcije izvedli tudi v fazi vlaženja zemljine. Izdelava retencijskih krivulj temelji na podlagi uporabe različnih matemačnih modelov za opis retencijskih krivulj. Dobljene krivulje smo primerjali med preiskovanimi zemljinami in med uporabljenimi modeli ter opazovali, kateri model se izmerjenim vrednostim najbolje približa. Rezultati so pokazali dobro prileganje retencijskih krivulj izmerjenim vrednostim in ujemanje izmerjenih vrednosti sukcije z že znami rezultati iz literature. The thesis deals with laboratory testing of unsaturated soils, with an emphasis on investigation of soil suction phenomenon. Soil suction is referred to as the free energy state of soil water. In geotechnics suction is measured using a variety of methods, with the chief interest in the values of matrix suction. At the Slovenian National Building and Civil Engineering Institute suction was measured using Bishop-Wesley doublewall triaxial cell apparatus and dew point potentiometer, where the measurements were carried out in order to determine soil water characteristic curve in the phase of drying samples. Research was performed on two different types of materials: very stiff sandy silt and on samples of silty clay. Very stiff silt is very rare at construction sites in Slovenia and such areas therefore receive extensive geotechnical research. Especially worrying is the change in strength properties in relation to saturation, since they are prone to crushing or collapse when wet or overloaded. Selected samples were first subject to basic soil classification tests: sieve analysis, measurements of humidity and bulk density. In addition to the measurement of suction in the drying phase, suction measurements were also carried out at the stage soil moistening. Soil water characteristic curve was based on the use of different mathematical models to describe retention curves. The resulting curves were compared to the trial earths and the models used in order to determine which model fits best the measured values. The results showed good fit of retention curves to measured values. Our results also corresponded to the measured values of suction in other research papers and scholarly articles.