Hydraulic fracturing is a multi-physics multi-scale problem related to natural processes such as the formation of dikes. It also has wide engineering applications such as extraction of unconventional resources, enhanced geothermal energy and carbon capture and storage. Current simulators are highly simplified because of the assumption of homogeneous reservoir. Unconventional reservoirs are heterogeneous owing to the presence of natural fracture network. Because of high computational effort, three-dimensional multi-scale simulations are uncommon, in particular, modelling material as a heterogeneous medium. Lattice Element Method (LEM) is therefore proposed for multi-scale simulation of heterogeneous material. In LEM, material is discretised into cells and their interactions are modelled by lattices, hence a three-dimensional model is simplified to a network of one-dimensional lattice. Normal, shear and rotational springs are used to define the constitutive laws of a lattice. LEM enables desktop computers for simulation of a lattice model that consists of millions of lattices. From simulations, normal springs govern the macroscopic bulk deformation while shear springs govern the macroscopic distortion. There is fluctuation of stresses even under uniform loading which is one of the characteristics of a lattice model. The magnitude increases with the stiffness ratio of shear spring to normal spring. Fracturing process can be modelled by LEM by introducing a microscopic tensile strength and a microscopic shear strength to the lattice properties. The strength parameters can be related to fracture toughness with the length scales of cells. From simulations, the relationships between model parameters and macroscopic parameters that are measurable in experiments are identified. From the simulations of uni-axial tension tests, both the spring stiffness ratio and the applied heterogeneity govern the fracturing process. The heterogeneity increases the ductility at the expense of the reduction on the macroscopic strengths. Different stages of fracturing are identified which are characterised by the model heterogeneity. Heterogeneous models go through the stages of the spatially distributed microscrack formation, the growth of multiple fracture clusters to the dominant fracture propagation. For homogeneous models, one of the microcracks rapidly propagates and becomes a dominant fracture with the absence of intermediate stages. From the uni-axial compression test simulations, the peak compressive stress is reached at the onset of the microscopic shear crack formation. Ductility is governed by the stiffness reduction ratio of a lattice in closed fractured stage to its unfractured stage. A novel Dual Lattice Model (DLM) is proposed for hydraulic fracture simulation by coupling a solid lattice model with a fluid lattice model. From DLM simulations of hydraulic fracturing of the classical penny shape crack problem under hydrostatic condition, the heterogeneities from both the fracture asperity and the applied heterogeneity increase the apparent fracture toughness. A semi-analytical solution is derived to consider the effect of fluid viscosity in the elastic deformation regime. Two asymptotes are identified that gives steep pressure gradients near the injection point and near the fracture tip which are also identified in the DLM simulations. Simulations also show three evolving regimes on energy dissipation/transfer mechanisms: the viscosity dominant, the elastic deformation dominant and the mixture of elastic deformation and toughness.

[pt] Este trabalho tem como finalidade comparar e analisar diferentes modelos numéricos na análise do processo de queda de blocos com diferentes geometrias, para que seja possível determinar os riscos à infraestrutura e à população local que este evento pode causar. Foram utilizados o software RAMMS e o programa de modelagem PFC3D para simulação de queda de blocos. O primeiro foi desenvolvido pelo instituto suíço WSL, o software utiliza a dinâmica não suave (nonsmooth), não havendo penetração dos blocos com a superfície, e as leis de contato são feitas por restrições. O segundo utiliza o método dos elementos discretos através de dinâmica de contato suave. Na primeira parte do trabalho foram realizadas simulações de casos simples de queda de blocos para ambos os modelos, a fim de analisar o principal parâmetro do contato rocha-solo de cada programa com o alcance das rochas. O modelo de contato no programa PFC3D utilizado foi o método linear, e depois foi adicionada uma força de resistência ao rolamento para que o modelo conseguisse reproduzir o comportamento de solos mais macios. Os modelos foram simulados para casos reais, primeiro foram aplicados para uma encosta na BR116, onde um evento de deslizamento já tinha ocorrido. Foram realizadas simulações com os dois modelos na região, comparando-os e analisando com os vestígios deixados pelo evento. Outro caso estudado foi o de blocos susceptíveis ao deslizamento no bairro Glória, no município de Petrópolis. E por último, foram criados modelos para analisar o comportamento da vegetação em ambos os modelos. Com os resultados obtidos, conclui-se que o PFC3D consegue simular o processo de queda com melhor precisão através do auxílio da força de resistência ao rolamento. Para ambas simulações, o caso da BR116 e o do bairro Glória, os modelos apresentarem uma mesma tendência quanto a trajetória do bloco, mas melhorias na calibração do modelo linear com resistência ao rolamento precisam ser realizadas para que melhores resultados sejam obtidos. A presença de vegetação se mostrou como um mecanismo muito eficiente para perdas de energia no sistema, diminuindo significativamente a velocidade dos blocos. / [en] The aim of this work is to compare and analyze different numerical models on the rockfall process with different geometries, to determine the risks to the local infrastructure and population. It was used the software RAMMS and the modeling program PFC3D to simulate rockfall events. The first software was developed by the Swiss institute WSL, it uses the nonsmooth dynamics system, it is a dynamic behavior where there is no penetration between the rock and the surface and the contact laws are created by restrictions laws. And the second one uses the discrete element method applying the smooth dynamics system to simulate the event. On the first part of the work, numerical models were created on both models to simulate simple cases of rockfall events, to compare the main soil-rock parameter of both modeling program with the distance reached of the rocks. The contact model used on the PFC3D program was the linear method, and after the first simulations was added a rolling resistance force to the model reproduce soft. Both models were applied to real cases, the BR116 was the first case modeled, where some natural hazards have already happened. The results of the numerical simulations were compared and analyzed. It was also created a model to simulate the rockfall event of the Gloria neighborhood, in Petropolis; rocks that could fall were determined and simulations for those blocks were performed, the deposition area and the blocks trajectory of each model were examined. And finally, it was studied the vegetation effect of each model and its particularities. Through the results, it is possible to conclude that the PFC3D can simulate the rockfall process with better accuracy using the rolling resistance method. For both simulation, the BR116 and the Gloria neighborhood, the models showed the same tendency of the blocks trajectory, but it is necessary to improve the calibration of the rolling resistance coefficient. The existence of the vegetation revealed as a very effect lose energy mechanism on the system, decreasing significantly the velocity of the blocks.

[pt] O estudo sobre estabilidade de poços tem como uma de suas principais aplicações a determinação da faixa segura de densidades do fluido de perfuração. A análise de estabilidade de um poço, que determina essa faixa segura, envolve uma série de parâmetros que geralmente apresentam incertezas associadas aos seus valores. Em métodos convencionais, essas incertezas não são consideradas. O objetivo deste trabalho é desenvolver metodologias de análise de estabilidade de poços que considerem as incertezas associadas aos parâmetros. Métodos para quantificação de incertezas associadas aos parâmetros são apresentados para o caso de um poço já perfurado e para o caso de um novo poço em uma região em desenvolvimento. Dois métodos de análise de sensitividade também são apresentados e aplicados ao problema de estabilidade de poços. Para avaliação do efeito que as incertezas associadas aos parâmetros geram no sistema de estabilidade, dois métodos probabilísticos (simulação de Monte Carlo e método FOSM) foram aplicados ao problema, e depois intercomparados. Através do método da simulação de Monte Carlo, desenvolveu- se um simulador computacional para análise probabilística de estabilidade de poços, que permite a consideração das incertezas associadas aos parâmetros. Os métodos probabilísticos de análise fornecem como resposta as probabilidades de ruptura associadas às diferentes pressões internas do poço. Como essas pressões são dependentes da densidade do fluido de perfuração, a avaliação do risco associado à essas pressões constitui um novo critério para a determinação da densidade do fluido de perfuração. / [en] The study on wellbore stability has as one of its main application the determination of the safe range of the drilling-fluid density. The wellbore stability analysis is controlled by a number of parameters that generally present uncertainties associated to their values. In conventional methods, these uncertainties are not considered. The purpose of this work is to develop methodologies of analysis of wellbore stability that consider the uncertainties associated to the controlling parameters. Methods for quantifying the uncertainties associated to the parameters are presented for the case of an open well and for the case of new well located on a development region. Two methods of sensitivity analysis are also presented and applied to the well stability problem. To evaluate the effect that the uncertainties associated to the parameters create on the stability analysis, two probabilistic methods were applied to the problem, and compared to each other. Based upon Monte Carlo method, a computational simulator was developed in order to carry out probabilistic analysis of wellbore stability. The simulator takes into account the uncertainties associated to the parameters. The probabilistic methods of analysis, presented in this dissertation, provide the probability of failure associated to the different internal pressure of the well. As these pressures are dependent upon the density of the drilling - fluid, the evaluation of the risk associated to these pressures constitutes a new criterion to establish the density of the drilling -fluid. / [es] EL estudio sobre estabilidad de pozos tiene como una de sus principales aplicaciones la determinación de la banda de seguridad de las densidades del fluido de perforación. El análisis de estabilidad de un pozo, que determina esa banda segura, incluye una série de parámetros que generalmente presentan errores asociados a sus valores. En métodos convencionales, esos errores no son consideradas. EL objetivo de este trabajo es desarrollar metodologías de análisis de estabilidad de pozos que consideren los errores asociados a los parámetros. Métodos para cuantificación de errores asociadas a los parámetros son presentados para el caso de un pozo perforado y para el caso de un nuevo pozo en una región en desarrollo. Se presentan también dos métodos de análisis de sensitividad y se aplican a problemas de estabilidad de pozos. Para la evaluación de lo que los errores asociados a los parámetros generan en el sistema de estabilidad, se aplican dos métodos probabilísticos (simulación de Monte Carlo y método FOSM). A través del método de la simulación de Monte Carlo, se desarrolla un simulador computacional para el análisis probabilístico de estabilidad de pozos, que permite la consideración de los errores asociados a los parámetros. Los métodos probabilísticos de análisis dan como respuesta las probabilidades de ruptura asociadas a las diferentes presiones internas del pozo. Como esas presiones son dependientes de la densidad del fluido de perforación, la evaluación del riesgo asociado a esas presiones constituye un nuevo criterio para la determinación de la densidad del fluido de perforación.

L’influence de l’eau sur les propriétés mécaniques des roches a fait l’objet de peu d’études jusqu’à présent. Or dans de nombreuses situations, la différence entre le comportement mécanique de la roche sèche et saturée en eau peut être appréciable. De nouveaux champs d’application, tels que l’analyse des risques liés à l’après-mine ou les problématiques relatives au stockage souterrain des déchets nucléaires, requièrent actuellement une connaissance plus approfondie de ces aspects.<p><p>Cette étude expérimentale se propose donc de contribuer à une meilleure compréhension du comportement hydromécanique de matériaux rocheux partiellement saturés. Pour ce faire, la démarche suivie a consisté à se baser sur des techniques et outils bien établis pour les sols (meubles), et à les adapter aux matériaux rocheux. Dans ce contexte, une première étude a été menée sur un matériau rocheux argileux, le schiste de Beringen, et a permis d’évaluer l’influence de la succion pour les états de compression simple. <p><p>Suite à cette première étude, d’autres états de contrainte ont été envisagés, principalement au moyen de l’essai triaxial. Le contrôle de la succion en cours d’essai a demandé d’importantes transformations au système triaxial déjà disponible au laboratoire. En parallèle, un nouvel équipement, comprenant notamment un contrôle de la succion par la méthode de translation d’axes, a été conçu et mis en service. La suite du programme expérimental a été réalisée sur une roche poreuse et très homogène :le calcaire de Sorcy.<p><p>A l’état sec, les résultats d’essais triaxiaux et polyaxiaux ont permis la construction de surfaces de charge tridimensionnelles. En plan méridien, comme pour d’autres roches poreuses, la résistance augmente avec la pression de confinement lorsque celle-ci reste assez faible (inférieure à 15 MPa environ) ;le comportement est fragile. Aux confinements plus élevés, le comportement devient ductile. En plan octaédrique, la forme de la surface évolue depuis le triangle jusqu’au cercle dans la partie fragile, puis continue à évoluer vers un triangle (inversé par rapport au premier) dans le domaine ductile.<p><p>En conditions saturées, un ensemble cohérent de paramètres poroélastiques a été mesuré, parmi lesquels le coefficient de Biot (qui a été évalué à environ 0.85). La variabilité de ces paramètres entre échantillons et en fonction de l’état de contrainte a été examinée. Dans le domaine poroplastique, c’est la contrainte effective de Terzaghi qui se révèle contrôler le comportement mécanique, malgré que le coefficient de Biot soit inférieur à 1. En plan méridien, l’enveloppe obtenue pour le matériau saturé se rapproche de celle du matériau sec, moyennant une normalisation par rapport à sa longueur horizontale. Ceci suggère que la prise en compte des conditions non saturées pourrait se faire, comme souvent pour les sols, par l’ajout d’un axe supplémentaire :la succion.<p><p>En conditions non saturées, les essais réalisés en conditions isotropes à succion contrôlée montrent une forte augmentation du module d’incompressibilité drainé avec la pression de confinement et une faible augmentation avec la succion. Ceci tend à conforter les hypothèses adoptées.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Étant donné que le stockage de gaz naturel ou d’air comprimé dans des niveaux souterrains constitués de sel joue un rôle essentiel pour assurer l'approvisionnement en énergie sur le long terme, le gouvernement chinois a construit de nombreux lieu de stockage dans ces niveaux géologiques ces dernières années. En raison des variations saisonnières de la pression gaz / air, les entrepôts subissent des chargements cycliques qui provoquent la fatigue des roches et conduisent à des risques de rupture qu’il faut maîtriser pour des raisons liées à la sécurité et à l'environnement. La compréhension des processus de fatigue discontinue du sel sous chargement cyclique est donc très importante et fait l'objet de cette étude, qui se concentre sur des recherches expérimentales et le développement de modèles constitutifs décrivant la déformation sous fatigue. Cette thèse s’articule suivant la méthodologie suivante : ① des essais de chargement cyclique classique pour étudier les propriétés basiques de la fatigue dans le sel. ② des tests de charge cyclique discontinu pour explorer les processus de fatigue discontinue. ③ l’instrumentation pour détecter les émissions acoustiques afin de suivre l'évolution des dommages causés par la fatigue dans le sel. ④ Le développement à la base des résultats expérimentaux obtenus de modèle constitutif pour la fatigue discontinue. / Since the salt cavern storage of natural gas and compressed air plays a critical role in ensuring the energy supply and adjusting the seasonal imbalance of power, China government has been constructing numerous new storages in recent years. Because of the seasonal of the seasonal variations of the gas/air pressure, the storages undergo cyclic loading, which causes rock fatigue and induces the associated safety and environmental hazards. The investigation of the discontinuous fatigue of salt under cyclic loading is therefore very important and is the subject of this study, which focuses on the experimental investigations and the development of the constitutive models describing the fatigue deformation. This thesis includes the following principal parts: ① Conventional cyclic loading testing to investigate the basic properties of fatigue in salt. ② Discontinuous cyclic loading tests testing to investigate the discontinuous fatigue. ③ Acoustic emission detecting experimentation to track the evolution of the fatigue damage in the salt. ④ Development of the fatigue life model and constitutive model for the discontinuous fatigue, based on the obtained experimental results.

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Um die Vortriebsleistung von Maschinen zur Festgesteinsgewinnung zu steigern, wird das Prinzip der Aktivierung seit Jahren erfolgreich eingesetzt. Dabei wird der grundlegenden Arbeitsbewegung des eingreifenden Werkzeugs eine Schlag- oder Vibrationsbewegung überlagert. Im Rahmen der vorliegenden Arbeit wurde die Möglichkeit zur hochfrequenten Aktivierung von Werkzeugen im Eingriff in Festgestein untersucht. Ziel der Arbeit ist es, die Besonderheiten beim Eingriff hochfrequent aktivierter Werkzeuge in Festgestein genauer zu definieren und zu klären, auf welchen Ursachen sie beruhen. Es werden konventionelle und hochfrequente Aktivierungsprinzipien beispielhaft vorgestellt und ein kurzer Einblick in das untersuchte Aktivierungsprinzip und dessen Besonderheiten gegeben. Eine Literaturrecherche gibt Informationen zu den Eigenschaften von Gesteinen mit besonderem Fokus auf dynamisch veränderlichen Kennwerten. Weiterhin wird Literatur zu den physikalischen Grundlagen des Werkzeugeingriffs und der Piezoaktorik vorgestellt. Eine theoretische Verarbeitung dieser Informationen in Form von Modellen wird neben praktischen Versuchen an einem Prüfstand vorgenommen.:Abkürzungen 8 1 Motivation und Einleitung 8 2 Einführung in das Thema „Aktivierte Werkzeuge” 10 2.1 Konventionelle Aktivierung . . . . . . . . . . . . . . . . . . 10 2.2 Hochfrequente Aktivierung . . . . . . . . . . . . . . . . . . 12 2.2.1 Stand der Technik . . . . . . . . . . . . . . . . . . 12 3 Eingrenzung des Problems, Definition der Arbeitsaufgaben 16 3.1 Vorbetrachtungen . . . . . . . . . . . . . . . . . . . . . . . 16 3.2 Arbeitsplan . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4 Recherchen 20 4.1 Literaturrecherche zu den Eigenschaften von Gesteinen . . 20 4.1.1 Allgemeines . . . . . . . . . . . . . . . . . . . . . . 20 4.1.2 Elastizität . . . . . . . . . . . . . . . . . . . . . . . 20 4.1.3 Härte . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.1.4 Festigkeit . . . . . . . . . . . . . . . . . . . . . . . 22 4.1.5 Aufbau von Gesteinen . . . . . . . . . . . . . . . . 23 4.1.6 Versagen von Gesteinsstoffen . . . . . . . . . . . . . 25 4.1.6.1 Versagensart . . . . . . . . . . . . . . . . 25 4.1.6.2 Festigkeitshypothesen . . . . . . . . . . . 26 4.1.6.3 Bruchmechanik . . . . . . . . . . . . . . . 27 4.1.7 Dynamisch veränderliches Werkstoffverhalten . . . 27 4.1.7.1 Auswirkungen auf die elastischen Eigenschaften . . . . . . . . . . . . . . . . . . . . . . 28 4.1.7.2 Auswirkungen auf die Festigkeit . . . . . . 29 4.1.7.3 Ursachen der Dehnratenabhängigkeit . . . 30 4.2 Literaturrecherche zur Modellierung des Werkzeugeingriffs 33 4.2.1 Vorbetrachtungen . . . . . . . . . . . . . . . . . . . 33 4.2.2 Grundlagen . . . . . . . . . . . . . . . . . . . . . . 34 4.2.2.1 Elementarlösung nach Boussinesq . . . 35 4.2.2.2 Flächenpressung im Kontakt . . . . . . . . 36 4.2.2.3 Superposition zu einer Flächenlast . . . . 36 4.2.2.4 Verschiebung unter einem Werkzeug . . . 37 4.2.2.5 Versagenskriterium . . . . . . . . . . . . . 37 4.3 Literaturrecherche zur Modellierung der Piezoaktorik . . . 40 4.3.1 Vorbetrachtungen . . . . . . . . . . . . . . . . . . . 40 4.3.2 Grundlagen . . . . . . . . . . . . . . . . . . . . . . 41 5 Modellbildungen und Simulationen 46 5.1 Modellierung des Werkzeugeingriffs . . . . . . . . . . . . . 46 5.1.1 Kontaktproblem . . . . . . . . . . . . . . . . . . . . 46 5.1.2 Spannungsfeld unter einer Flächenlast . . . . . . . 48 5.1.3 Dehnraten im Eingriff . . . . . . . . . . . . . . . . 51 5.1.4 Dynamische Festigkeitssteigerung . . . . . . . . . . 51 5.1.5 Erstellen des Versagenskriteriums . . . . . . . . . . 52 5.1.6 Simulation des Werkzeugeingriffs . . . . . . . . . . 54 5.2 Modellierung der Piezoaktorik . . . . . . . . . . . . . . . . 55 5.2.1 Randbedingungen . . . . . . . . . . . . . . . . . . . 55 5.2.2 Modellbildung . . . . . . . . . . . . . . . . . . . . . 58 5.2.2.1 Elektrische Größen . . . . . . . . . . . . . 58 5.2.2.2 Mechanische Größen . . . . . . . . . . . . 61 6 Versuche 62 6.1 Voraussetzungen und Ziele . . . . . . . . . . . . . . . . . . 62 6.2 Planung und Ablauf . . . . . . . . . . . . . . . . . . . . . 63 6.2.1 Vorversuche zur Verifikation . . . . . . . . . . . . . 63 6.2.2 Hauptversuchsreihen . . . . . . . . . . . . . . . . . 64 6.2.2.1 Einfluss der Aktivierungsfrequenz . . . . . 65 6.2.2.2 Einfluss von Lastwechselzahl und Nennspannung . . . . . . . . . . . . . . . . . . . . . 65 6.3 Versuchsergebnisse . . . . . . . . . . . . . . . . . . . . . . 66 6.3.1 Vorversuche zur Verifikation . . . . . . . . . . . . . 66 6.3.2 Hauptversuchsreihen . . . . . . . . . . . . . . . . . 66 7 Diskussion 70 7.1 Dynamisch veränderliche Werkstoffeigenschaften . . . . . . 70 7.2 Simulationsergebnisse zum Werkzeugeingriff . . . . . . . . 72 7.2.1 Statischer Lastfall . . . . . . . . . . . . . . . . . . . 73 7.2.2 Dynamischer Lastfall . . . . . . . . . . . . . . . . . 73 7.2.2.1 Festigkeitssteigerung unter dynamischen Belastungen . . . . . . . . . . . . . . . . . . 73 7.2.2.2 Maximaler Beanspruchungsquotient . . . . 73 7.2.2.3 Verändertes Versagensverhalten . . . . . . 74 7.2.2.4 Einfluss des E-Moduls . . . . . . . . . . . 76 7.2.2.5 Einfluss der Querdehnzahl . . . . . . . . . 77 7.2.3 Unzulänglichkeit des verwendeten Versagenskriteriums 78 7.3 Modell der Piezoaktorik . . . . . . . . . . . . . . . . . . . 79 7.4 Versuchsergebnisse . . . . . . . . . . . . . . . . . . . . . . 80 7.4.1 Auswirkungen von Lastwechselzahl und Nennspannung 80 7.4.2 Auswirkungen der Aktivierungsfrequenz . . . . . . 81 7.4.2.1 Direkter Einfluss der Aktivierungsfrequenz 81 7.4.2.2 Einfluss der resultierenden Größen . . . . 83 7.4.3 Weitere Beobachtungen . . . . . . . . . . . . . . . . 84 7.5 Hinweise zur Anwendung der gewonnenen Erkenntnisse . . 85 7.6 Schlussfolgerungen . . . . . . . . . . . . . . . . . . . . . . 86 8 Zusammenfassung und Ausblick 87 Literaturverzeichnis 90 Anhang 97 Anhang A Aktivierte Werkzeuge 97 A.1 Schutzrechte . . . . . . . . . . . . . . . . . . . . . . . . . . 97 A.2 Ergebnisse vorausgegangener Arbeiten . . . . . . . . . . . 98 B Mechanische Kennwerte einiger Stoffe 99 C Zusatzinformationen zur Modellierung des Werkzeugeingriffs 100 C.1 Superpositionsmethode . . . . . . . . . . . . . . . . . . . . 100 C.1.1 Herleitung . . . . . . . . . . . . . . . . . . . . . . . 100 C.1.2 Verifikation . . . . . . . . . . . . . . . . . . . . . . 103 C.2 Impulsbilanz im Eingriff . . . . . . . . . . . . . . . . . . . 106 C.3 Simulationsergebnisse für den Eingriff . . . . . . . . . . . . 107 D Zusatzinformationen zur Modellierung der Piezoaktorik 113 D.1 Kennwerte . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 D.2 Herleitung der Ersatzkapazität . . . . . . . . . . . . . . . . 113 D.2.1 Einfluss der Feldstärke . . . . . . . . . . . . . . . . 113 D.2.2 Einfluss der Steifigkeit des Gesamtsystems . . . . . 114 D.3 Simulationsergebnisse . . . . . . . . . . . . . . . . . . . . . 116 E Zusatzinformationen zu den Versuchen 118 E.1 Messsystem am Prüfstand . . . . . . . . . . . . . . . . . . 118 E.1.1 Werkzeugkräfte . . . . . . . . . . . . . . . . . . . . 118 E.1.2 Eindringtiefe des Werkzeugs . . . . . . . . . . . . . 118 E.1.3 Werkzeugschwingwege . . . . . . . . . . . . . . . . 119 E.1.4 Elektrische Größen am Piezoaktor . . . . . . . . . . 119 E.2 Versuchsparameter . . . . . . . . . . . . . . . . . . . . . . 120 E.3 Werkstoffkennwerte der verwendeten Gesteine . . . . . . . 121 E.4 Messergebnisse . . . . . . . . . . . . . . . . . . . . . . . . 122

The Czech deep repository development programme resulted in identification of several localities with favourable geological conditions. The Czech concept of a deep repository construction targets on crystalline host rocks. The dissertation focuses on combined petrographic and physico-mechanical properties (rebound hardness, uniaxial and triaxial compressive strength, indirect tensile strength) of crystalline rocks (durbachite, ganulite) from the most favoured localities – Horka near Velké Meziříčí and Kraví hora near Dolní Rožínka.

Construction of rock slopes is needed in many civil work projects. It is for example very common in road and railway cuts, but other applications include excavation for tunneling or building foundations, where perhaps sensitive constructions are present in the immediate vicinity. In Sweden the majority of the rock is hard crystalline bedrock of relatively good quality, and the fracture orientation have a large effect of the stability of the rock slope.If the geology is not properly considered for when the design of the slope is carried out, it can result in slope failure, with severe consequences. This applies especially if the rock slope is high, but unwanted effects like increased excavation and construction costs, could occur also in smaller slopes if the risks are not identified and managed. However, it is difficult to standardize design of rock slopes in fractured hard crystalline rock because of the uncertainties and variations in the geological conditions during the design phase.Rock mass characterization systems like Rock mass rating, RMR (Bieniawski 1989) and the Qsystem (Barton, Lien och Lunde 1974) are commonly used to describe the general rock mass quality. Whilst a good rock mass quality is generally easier to construct in, stability problems do occur due to structural geology in rock slopes even in good rock mass quality. The application of these systems in rock slopes can be problematic as they do not describe the geometry of the slope and how the fractures daylight in the slope face. Instead, stereonets can be used to visualize this, but fracture parameters of large importance for stability (persistence, roughness and alteration) are traditionally not presented in a stereonet analysis. Additionally, these parameters and the structural geological conditions can be difficult to predict and can vary significantly over short distances, why it can be difficult to forecast and predict failure in the design face.Slope instability due to large sliding and wedge failures have been observed in a large number of slopes in crystalline rock, and a standard method for design of rock slopes is lacking. This has given rise to the research question of how best to describe rock mass conditions, how to design slopes in crystalline rock and how to manage these risks during construction.To investigate this, three rock slopes where large failure had occurred were selected for the case study and were mapped, characterized and analyzed. The results from the case study showed that all rock slopes investigated had in common that failure had occurred along fractures of large persistence. This highlights the importance of evaluating the geology in the correct scale and suggest that lineament studies and other elevation based interpretation are perhaps more useful than previously thought. It also came to light that the planning and design process is inflexible which in many cases lead to large risks being overlooked or left unnoticed.A flow chart for risk classification was produced and suggested for aid in decision making aiming at simplifying project management of rock slopes, as well as aiding in visualization of the risk that rock slopes can be associated to.

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