The paper presents a method of calculating deformation coefficients for any point situated in the overlying rock mass or on the ground surface. This solution was based on the method presented by Sroka and Schober (1982, 1987), taking into account new theoretical achievements and the current results of in situ measurements.

Vid en ombyggnation av Henriksdals reningsverk har ett vertikalschakt utformats och anlagts. Under berguttaget tillämpades extensometermätningar för att följa upp deformationer i en bergpelare mot en befintlig tunnel. Mätningar utfördes automatiserat och regelbundet. För uppföljning av deformationer tillämpades tre larmnivåer avgränsade av två larmgränser vid 1.0 mm samt 3.0 mm deformation och var förbundna till olika motåtgärder. Målet med detta arbete harvarit att studera hur tillämpade larmgränser har presterat relativt dokumenterade och prognostiserade deformationer ur ett sannolikhetsbaserat perspektiv. Samt vid behov formulera och föreslå nya larmgränser. En litteraturstudie om modellering av bergmassor samt mekaniska egenskaper hos förekommande bergmassa av gnejs genomfördes. Därefter modellerades objektet för vidare numerisk analys genom FEM i Plaxis 3D. Med grund i uppställd modell kunde in-situ spänningsfältet skattas och modellen optimeras. En känslighetsanalys för bergmassans hållfasthetsparametrar utfördes och de fyra mest känsliga parametrarna: γ, ν, σci, Qbas, applicerades statistiskt i efterföljande studier. Föreslagna och tillämpade larmgränser studerades genom utförande av Monte Carlo-simuleringar. Använda deformationsbaserade larmgränser återfanns inte vara tillfredsställande och nya individuella töjningsbaserade gränsvärden framställdes. De ursprungliga deformationsbaserade larmgränserna resulterade för längre mätankare i utlösta larm och visades vara ouppnåeliga för kortare mätankare. En resulterande sannolikhet för överskridande av föreslagna varningsgränser vid dragtöjning skattades till storleksordningen 10−2 till 10−1 samt för stoppgränserna vid dragtöjning till 10−4. Sannolikheterna för överskridande av föreslagna larmgränser vid trycktöjning var inte möjliga att uppskatta för det studerade fallet. / During a rebuild of Henriksdal wastewater treatment plant, a vertical rock shaft was constructed. During the excavation, extensometers were used for monitoring deformations in a rock pillar against an existing tunnel. Measurements were automatically and regularly performed. Three alarm levels for follow up of the deformations were used and associated with different counter measures. The alarm levels were divided by two alarm limits at 1.0 mm and 3.0 mm deformation. The goal with this work was to study how the applied alarm limits from a probabilistic point of view have performed relative to obtained and forecasted deformations. And, if necessary, propose new alarm limits. A literature study about modeling of rock masses and mechanical properties of the occurring gneiss at site was performed. The object was thereafter modeled for further numerical analyzes using FEM in Plaxis 3D. Based on the performed model, the in-situ stress field could be estimated,and the model was further optimized. A sensitivity analysis of the rock mass strength parameters was conducted and the four most sensitive parameters: γ, ν, σci, Qbas, were applied as probabilistic in the following studies. Proposed and applied alarm limits were studied through Monte Carlo simulation. Applied deformation-based alarm limits were found not to be sufficient and two new strain-based were prescribed. The deformation-based limits were for the longer extensometer anchors resulting in triggered alarms and were only considered to be applicable for anchor lengths between 3.0 to 5.0 m. The probability of exceeding the proposed warning limits for tensile strain was estimated to be of a magnitude 10−2 to 10−1 and for the stop limits to be of a magnitude 10−4. The probabilities of exceeding the proposed alarm limits during compressive strain were not possible to estimate for the studied case.

Determination of the subsurface geology is very important for the rock quarry industry. This is primarily done by drilling and mapping of the surface geology. However in Sweden the bedrock is often completely covered by Quaternary sediments making the prediction of subsurface geology quite difficult. Incorrect prediction of the rock-mass quality can lead to economic problems for the quarry. By performing geophysical measurements a more complete understanding of the subsurface geology can be determined. This study shows that by doing 2D-parallel data sampling a 3D inversion of the dataset is possible, which greatly enhances the visualization of the subsurface. Furthermore the electrical resistivity technique together with the induced polarization method proved to be very efficient in detecting fracture frequency, identification of major fracture zones, and variations in rock-mass quality all of which can affect the aggregate quality. With this technique not only the rock-mass quality is determined but also the thickness of the overburden. Implementation of geophysics can be a valuable tool for the quarry industry, resulting in substantial economic benefits. / QC 20101118

In the construction of a tunnel, the characterization of the rock mass is performed in three different steps, in the pre-investigations, in the engineering geological forecast and in the tunnel mapping during construction. There has in previous work been observed that discrepancies exist between the results from these different steps, with a tendency to assign poorer rock mass quality in the tunnel mapping than in the pre-investigations and in the engineering geological forecast. One example is the work done by Kjellström [1] on the Cityline where the divergence in rock mass quality was analyzed between the different steps. If a divergence exists between the engineering geological forecast and the actual conditions observed in the tunnel mapping, it will influence both planning and budget. It is therefore important that the engineering geological forecast is as close as possible to the actual rock mass conditions in the field. The aim of this thesis was, using the case study of the Northern Link, to analyze those discrepancies in the rock mass quality estimated in the characterization and in the classification between the mapping of drill cores, the engineering geological forecast and the tunnel mapping thus complementing the work by Kjellström [1]. The aim was also identifying which parameters included in the Q-system that causes these discrepancies The analysis of the results showed that it is difficult to make the engineering geological forecast and the actual mapping match for every single meter, but that the overall correlation between them was good. The methodology used in the characterization and classification in the different phases (drill-core mapping, engineering geological forecast, tunnel mapping) may to some extent explain this divergence. The parameters Jr, Jn and Ja, included in the Q-system were the ones identified as having the largest influence on the discrepancies. In future work, it is recommended that focus is given on these parameters. A way to improve future engineering geological forecast for tunnel contracts would be to have a better follow up of the engineering geological forecast and to have standardized guidelines on how to assess clearly the value of the Q parameters in each phase (for the drill cores as well as for the actual mapping). The reduction of those differences would then lead to a better planning and budget management in future tunnel projects in Sweden.

La conception des ouvrages de génie civil dans les massifs rocheux fracturés nécessite une connaissance de leur comportement lors des travaux. Les ma ssifs fracturés sont généralement très complexes et représentés par des matrices et des discontinuités rocheuses. Cette thèse a pour objectif d'étudier le comportement mécanique du massif du futur tunnel de St Béat. La thèse est divisée en trois parties. Nous étudions tout d'abord les phénomènes prépondérants et les facteurs agissant sur le comportement mécanique des massifs rocheux. Dans la seconde partie, nous effectuons séparément des études expérimentales sur le comportement mécanique de la matrice et des discontinuités rocheuses. Enfin, dans la dernière partie, nous présentons une modélisation en 2D du comportement du massif fracturé lors du creusement du tunnel. L'étude expérimentale s'appuie sur des marbres rencontrés sur le site du tunnel. Le comportement de la matrice rocheuse est étudié à partir des essais de compression triaxiale sur des échantillons de roche saine. L'évolution de l'endommagement est caractérisée à l'aide des mesures de vitesses de propagation des ondes élastiques. Une enveloppe de rupture selon le critère linéaire de Mohr-Coulomb est proposée pour la matrice rocheuse. Le comportement au cisaillement des discontinuités naturelles est ensuite étudié sous différentes conditions de chargement (contrainte normale constante et rigidité normale imposée). La mesure de topographie des surfaces des discontinuités avant et après chaque essai mécanique permet de déterminer les paramètres statistiques de la rugosité. L'influence de la contrainte normale, la rigidité normale imposée, la rugosité initiale et la vitesse de cisaillement sur le comportement des discontinuités est mise en évidence. Des lois de comportement pertin entes sont proposées pour chaque type d'essais.Les caractéristiques mécaniques obtenues sont alors introduites dans le code de calcul UDEC afin de modéliser le comportement du massif en présence du tunnel, sous différentes conditions aux limites. La réponse en terme de déformations et de contraintes induites autour du tunnel est analysée / The design of civil engineering structures in fractured rock masses requires knowledge of their mechanical behavior. The fractured rock masses are usually very complex and separated in matrix and rock discontinuities. This thesis aims to study the mechanical behavior of St Beat tunnel rock mass. The thesis is divided into three parts. We study first the predominant phenomena and factors affecting the mechanical behavior of rock masses. In the second part, we perform separately experimental studies on the mechanical behavior of matrix and rock discontinuities. Finally, in the last section, we present a 2D model of the fractured rock mass behavior during the digging of the tunnel. The experimental study is based on the marbles encountered on the future tunnel site. The rock matrix behavior is studied using triaxial compression tests on intact rock samples. The damage evolution is characterized using propagation velocities measurements of elastic waves. A failure envelope by Mohr-Coulomb linear criterion is proposed for the rock matrix. The shear behavior of natural discontinuities is investigated under different loading conditions (normal stress or constant normal stiffness imposed). The discontinuities surfaces topography is measured before and after each mechanical test to determine the roughness statistical parameters. The influence of the normal stress, the normal stiffness, the initial roughness and the shear rate on the discontinuities behavior is demonstrated. A behavior law is proposed for each type of test.The mechanical properties obtained are introduced into the code UDEC to model the rock mass behavior with the presence of the tunnel, under different boundary conditions. The response in terms of deformations and stresses induced around the tunnel is analyzed

The geological disposal of nuclear waste, in underground openings and the long-term performance of these openings demand a detailed understanding of fundamental rock mechanics. A full scale field experiment: Äspö Pillar Stability Experiment was conducted at a depth of 450 m in sparsely fractured granitic rock to examine the rock mass response between two deposition holes. An oval shaped tunnel was excavated parallel to the σ3 direction to provide access to the experiment and also provide elevated stress magnitudes in the floor. In the tunnel floor two 1.75-m diameter 6-m deep boreholes were excavated so that a 1-m thick pillar was created between them. In one of the holes a confinement pressure of 700 kPa was applied and in the other displacement transducers were installed. The pillar volume was monitored by an Acoustic Emission System. Spatially distributed thermocouples were used to monitor the temperature development as the pillar was heated by electrical heaters. The excavation-induced stress together with the thermal-induced stress was sufficient to cause the wall of the open borehole to yield. The temperature-induced stress was increased slowly to enable detailed studies of the rock mass yielding process. Once the rock mass loading response was observed, the rock mass was unloaded using a de-stress slotting technique. This thesis focuses on the in-situ study of the rock mass response to coupled mechanical thermal loading and thermal-mechanical unloading. The experiment, its design, monitoring and observations are thoroughly described. An estimate of the yielding strength of the rock mass is presented and compared with laboratory test and results from other rock mass conditions reported elsewhere in the open literature. General conclusions about the effect of the confining pressure and the observations from the unloading of the pillar are also presented. Important findings are that the yielding strength of the rock mass has been successfully determined, low confinement pressures significantly affects the onset of yielding, the primary mode of fracture initiation and propagation is extensional, no significant time dependency of the yielding process was observed. The unloading studies also indicated that what appeared to be shear bands likely was a propagating zone of extensile failure that weakened the rock so that displacements in the shear direction could occur. / <p>QC 20100622</p>

In this thesis, suggestion of appropriate excavation and support systems and selection of rock mass strength parameters for the determination of these systems were carried out for the &Ccedil / ubukbeli Tunnel in Antalya. &Ccedil / ubukbeli Tunnel is a twin tube flute shaped tunnel with 1985 m length, 12 m width, 10 m height and maximum overburden thickness of 130 m. The tunnel area consists of limestone, clayey limestone, claystone, marl and siltsone. Rock mass classification systems are used for evaluation of rock mass characteristics and estimation of strength parameters. Selection of appropriate numerical method and software tool, namely Phase2, is accomplished after an extensive literature survey. The rock mass was divided into sections according to the RMR, Q, NATM and GSI classification systems along the tunnel and excavation and support systems were determined empirically along these sections. Thereafter, geomechanical parameters (i.e. modulus of deformation Em, Hoek-Brown material constants m and s etc.) were selected based on these classification systems. Finite element analysis was carried out as the final step of the design in order to investigate deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems. As the result of design studies accomplished along tunnel route, B1, B2, B3 and C2 type rock classes are assumed to be faced during construction of &Ccedil / ubukbeli Tunnel and appropriate excavation and support systems are proposed for these rock classes.

Most rock masses encountered in civil and mining engineering projects contain pre-existing discontinuities. These discontinuities weaken the rock masses to an extent, which depends very much on the size of engineering structure relation to discontinuity spacing. The strength and deformability of rock mass is controlled not only by the intact portion of rock, but by the characteristic of the joints that break up the mass, particularly their pattern and their orientation with respect to the in-situ stresses. In considering the effect of joints, the discrete approach emerged as an efficient tool and advocated since 1970s (Cundall, 1971). However, the numerical approach with modelling the joints explicitly has the limitation of computational complexity for modelling large-scale problems with extremely large number of joints. As an alternative to this limitation, the equivalent continuum approach models the jointed rock masses as a continuum with the equivalent properties that represent implicitly the effects of the joints. Several numerical methods have been developed by various researchers to model jointed rock masses as equivalent continuum, using various techniques. However, the existing equivalent continuum models are complicated and need more input data from experimental or field testing in order to carry out the analysis. Present approach attempts to use statistical relations, which are simple and obtained after analyzing a large data from the literature on laboratory test results of jointed rock masses. Systematic investigations were done including laboratory experiments to develop the methodologies to determine the equivalent material properties of rock mass and their stress-strain behaviour, using a hyperbolic approach (Duncan and Chang, 1970). Present study covers the development of equivalent continuum model for rock mass right from developing statistical correlations to find out equivalent material properties based on experimental results, to the implementation of the model in FLAC3D for 3-dimensional applications and subsequently verification leading to real field application involving jointed rocks. Experimental work carried out to study the strength and deformation characteristics of jointed rock by using standard laboratory tests on cylindrical specimens of plaster of Paris by introducing artificial joints. The objective was to derive the compressive strength and elastic modulus of rock mass as a function of intact rock strength/modulus and joint factor. The obtained experimental results and developed relations were compared with the previous experimental data on jointed rocks. Further, a failure criterion as proposed by Ramamurthy (1993) has been validated from these experimental results of intact and jointed rock specimens. Empirical relationships similar to Ramamurthy’s relations are established for the prediction of rock mass strength and were compared with proposed equation by Ramamurthy (1993) and are found comparable. However, the equations by Ramamurthy were based on different variety of rocks and therefore recommended for further use and were used in numerical models. For efficient application to the field problems the equivalent continuum model is implemented in the program Fast Lagrangian analysis of continua (FLAC3D). The model was rigorously validated by simulating jointed rock specimens. Element tests were conducted for both uniaxial and triaxial cases and then compared with the respective experimental results. The numerical test program includes laboratory tested cylindrical rock specimens of different rock types, from plaster of Paris representing soft rock to granite representing very hard rock. The results of the equivalent continuum modelling were also compared with explicit modelling results where joints were incorporated in the model as interfaces. To represent highly discontinuous system, the laboratory investigation on block jointed specimens of gypsum plaster (Brown and Trollope, 1970) was modelled numerically using equivalent continuum approach. To extend the applicability of the model to field applications, investigation were done by undertaking numerical modelling of two case studies underground caverns, one Nathpa Jhakri hydroelectric power cavern in Himachal Pradesh, India, and the other one Shiobara hydroelectric power cavern in Japan. This study verifies the efficiency of the present approach in estimating ground movement and stress distribution around the excavations in jointed rock masses. The modelling results were also compared with six other computation models as presented by Horii et al. (1999) for the Shiobara power house cavern. An attempt has also been made to numerically model the support system for the cavern and investigate the efficiency of reinforcements using FLAC3D. The model was also used for analyzing large scale slope in jointed rocks using the equivalent continuum model by undertaking numerical modelling of Anji bridge abutment slopes, in Jammu and Kashmir, India. Slope stability analysis is done using equivalent continuum approach for both, the original profiles as well as with the pier loads on cut profiles. Attempt was also made to exhibit the shear strength dependency of the strain though the hyperbolic stress- strain model. The shear strain developed in the slope increases with reducing the shear strength. The relationship between the shear strength reduction ratio ‘R’ and axial strain ‘ε’, for different values of failure ratio ‘Rf’ was studied and it was observed that, the value of ‘ε’ increases, as the value of ‘R’ increases especially it increases rapidly when the value ‘R’ approaches certain critical value, which varies with the value of ‘Rf’. This critical value of R is known as the critical shear strength reduction factor Rc and is highly sensitive to the confining stress. As the value of Rf increases, representing a transition from linear elastic nature to nonlinear nature, the value of critical shear strength reduction ratio also decreases. Relationship between the critical shear strength reduction ratio and the safety factor were examined to elucidate their physical meaning. It was observed that at critical value of the shear strength reduction ratio, a well defined failure shear zone developed from the toe to the crest of the slope. Intelligent models using ANNs were also developed to predict the elastic modulus of jointed rocks as an alternative to empirical equations and without predefining a mathematical model to correlate the properties.

Αντικείμενο της παρούσας διατριβής αποτελεί η διερεύνηση των μηχανικών παραμέτρων του βραχώδους υλικού και η εφαρμογή αυτών στην εκτίμηση της αντοχής και παραμορφωσιμότητας της βραχομάζας. Προς την κατεύθυνση αυτή, έγινε οριοθέτηση της μηχανικής συμπεριφοράς του βραχώδους υλικού, διατύπωση συσχετίσεων μεταξύ των φυσικών και μηχανικών παραμέτρων του καθώς και ημιποσοτική εκτίμηση της επίδρασης της ορυκτολογικής σύστασης στη διαφοροποίηση της συμπεριφοράς τους. Η επεξεργασία των αποτελεσμάτων της έρευνας έγινε μέσω ενός «Σχεσιακού Συστήματος Διαχείρισης Φυσικών και Μηχανικών Παραμέτρων Γεωλογικών Υλικών» που σχεδιάστηκε και δημιουργήθηκε στα πλαίσια της Διατριβής. Η έρευνα εστιάστηκε σε ιζηματογενή πετρώματα, χημικά (ασβεστόλιθους) και κλαστικά (ψαμμίτες και ιλυόλιθοι του φλύσχη) που συναντώνται εκτεταμένα στη Δυτική Ελλάδα καθώς επίσης και σε μεταμορφωμένα πετρώματα (μάρμαρα). Η δειγματοληψία των ιζηματογενών πετρωμάτων επικεντρώθηκε στους σχηματισμούς που απαρτίζουν τις γεωτεκτονικές ζώνες των Εξωτερικών Ελληνίδων, οι οποίες καλύπτουν το δυτικό ήμισυ του Ελλαδικού χώρου και φιλοξενούν πλήθος τεχνικών έργων. Για τα μεταμορφωμένα, δείγματα μαρμάρων λήφθηκαν από λατομεία της Βόρειας Ελλάδας που περιλαμβάνονται στις ζώνες των Εσωτερικών Ελληνίδων. Συνολικά, στα πλαίσια της έρευνας λήφθηκαν βραχώδη τεμάχη από 62 θέσεις δειγματοληψίας από τα οποία διαμορφώθηκαν και εξετάστηκαν ως προς τις φυσικές, δυναμικές και μηχανικές τους ιδιότητες 519 δείγματα βραχώδους υλικού. Ειδικότερα πρόκειται για 33 θέσεις δειγματοληψίας σε ασβεστολιθικούς σχηματισμούς (271 δοκίμια), 22 θέσεις σε σχηματισμούς του φλύσχη (152 δοκίμια ψαμμίτη και 24 δοκίμια ιλυόλιθου) και 7 θέσεις σε μάρμαρα (72 δοκίμια). Για κάθε θέση δειγματοληψίας διαμορφώθηκαν, με εργαστηριακό αδαμαντοτρύπανο, αδαμαντοτροχό και συσκευή λείανσης, έξι δοκίμια για τον εργαστηριακό προσδιορισμό των φυσικών, των δυναμικών και των μηχανικών παραμέτρων του βραχώδους υλικού. Οι εργαστηριακές δοκιμές πραγματοποιήθηκαν σύμφωνα με τις προδιαγραφές της ISRM (1981), του ΥΠΕΧΩΔΕ (Ε102-84) καθώς και της ASTM (D 2664 – 86, D 2938 – 86, D 2845 – 90, D 3967 – 92, D 3148 – 93). Έτσι, συνολικά εκτελέστηκαν: • 476 δοκιμές προσδιορισμού του πορώδους n (%), ξηρής πυκνότητας ρd (kN/m3), κορεσμένης πυκνότητας ρsat (kN/m3), λόγου κενών e και δείκτη κενών Iv (%). • 249 δοκιμές προσδιορισμού της ταχύτητας διάδοσης των υπερήχων Vp και Vs (m/sec). • 336 δοκιμές προσδιορισμού της σκληρότητας SHV. • 120 δοκιμές προσδιορισμού του δείκτη σημειακής φόρτισης Is(50) (MPa). • 67 δοκιμές προσδιορισμού της αντοχής σε μοναξονική θλίψη σc (MPa) από τις οποίες οι 58 έγιναν με σύγχρονη μέτρηση των αξονικών και πλευρικών παραμορφώσεων για τον προσδιορισμό του μέτρου ελαστικότητας Ε και του λόγου Poisson ν. • 75 δοκιμές προσδιορισμού της αντοχής σε εφελκυσμό σt (MPa). • 62 τριαξονικές δοκιμές. Κατά την αξιολόγηση των αποτελεσμάτων των εργαστηριακών δοκιμών κρίθηκε σκόπιμη η προετοιμασία και παρατήρηση στο μικροσκόπιο 20 λεπτών τομών που προήλθαν από διαφορετικά δείγματα με σκοπό την καλύτερη πληροφόρηση σχετικά με την ορυκτολογική σύσταση και τη δομή των βραχωδών υλικών που εξετάστηκαν. Μετά το πέρας των εργαστηριακών δοκιμών τα αποτελέσματα αυτών συγκεντρώθηκαν και αξιολογήθηκαν. Ακολούθησε στατιστική επεξεργασία από την οποία προέκυψαν ιστογράμματα διακύμανσης των τιμών της κάθε παραμέτρου και οριοθετήθηκε η συμπεριφορά των βραχωδών υλικών που εξετάστηκαν. Επιπλέον, μεταξύ των διαφόρων παραμέτρων του βραχώδους υλικού σχεδιάστηκαν τα αντίστοιχα διαγράμματα συσχέτισης και προτάθηκαν εμπειρικές σχέσεις που συνδέουν αυτές. Επίσης, πολύ σημαντικές ποιοτικές και ημιποσοτικές εκτιμήσεις προέκυψαν από τη συσχέτιση των παραμέτρων αντοχής με την ορυκτολογική σύσταση των βραχωδών υλικών. Μετά την ολοκλήρωση των εργαστηριακών δοκιμών στα πλαίσια της παρούσας διατριβής οι παράμετροι αντοχής (αντοχή σε μοναξονική θλίψη και σταθερά mi) που υπολογίστηκαν για το βραχώδες υλικό χρησιμοποιήθηκαν για την εκτίμηση κυρίως της αντοχής της βραχομάζας. Για το σκοπό αυτό εκτιμήθηκε ο Γεωλογικός δείκτης Αντοχής, GSI, σε 32 συνολικά θέσεις και προσδιορίστηκαν με τη χρήση του προγράμματος Roclab οι παράμετροι αντοχής της βραχομάζας για τις θέσεις αυτές. Στη συνέχεια και για να διερευνηθεί η επίδραση της διακύμανσης των παραμέτρων του βραχώδους υλικού στη συμπεριφορά της βραχομάζας υπολογίστηκαν οι παράμετροι αντοχής και παραμορφωσιμότητάς της με βάση τις προτεινόμενες από τη βιβλιογραφία τιμές του mi και όχι αυτές που υπολογίστηκαν εργαστηριακά. Από τη σύγκριση των δύο αποτελεσμάτων προέκυψαν χρήσιμα συμπεράσματα σχετικά με τη σημασία των εργαστηριακών δοκιμών αλλά και τη σημαντική επίδραση που έχουν οι ακριβείς τιμές των παραμέτρων του βραχώδους υλικού στην εκτίμηση της αντοχής της βραχομάζας. / The aim of this thesis is the determination of the mechanical properties of intact rock and their application to the estimation of the strength and deformability of the rock mass. There has been made an attempt to set up the boundaries in rock material behavior and to formulate empirical correlations between rock material parameters. In the frame of the current research a data base has been developed in order to file all laboratory testing results that had been conducted before in Greece by the Laboratory of Engineering Geology in University of Patras as well as the Central Public Works Laboratory. There has been recorded a total number of 5885 entries which correspond to an equal amount of rock specimens subjected to laboratory tests of their physical and/or mechanical properties. The research was focused on triaxial tests of clastic and chemical sedimentary rock specimens as well as marble rock specimens. Clastic and chemical sedimentary rocks are known to be the most widespread rock formations in Western Greece and a lot of major constructions have been made on or within these formations. Block samples were collected from 62 different sites in Greece, in order to be investigated through laboratory testing procedures. After the cutting of the samples laboratory tests were conducted in 519 cylindrical specimens. From these sites 33 were in limestones (271 specimens), 22 in flysch formations (152 sandstone specimens and 24 siltstone specimens) and 7 in marbles (72 specimens). Laboratory core drill and saw machines were used to cut the samples and end faces were ground in order to provide cylindrical specimens in size, shape and ends geometries according to testing requirements. The execution of laboratory tests was in accordance with ISRM suggested methods (1981, 1986) and ASTM standards (D 2664 – 86, D 2938 – 86, D 2845 – 90, D 3967 – 92, D 3148 – 93). More specifically the following laboratory tests were conducted: • 476 tests for porosity n (%), ρd (kN/m3), ρsat (kN/m3), e and Iv. • 249 tests for sound velocities (Vp and Vs). • 336 SHV tests. • 120 point load tests. • 67 uniaxial compressive tests with determination of modulus of deformation E and Poisson ratio, ν (in 58 UCS tests). • 75 brazilian tests. • 62 triaxial tests for rock material constant mi determination. During the evaluation of the results of laboratory testing, 20 thin sections have been made corresponding to different samples, in order to provide all the information as far as the mineralogy and structure of the samples are concerned. Statistical analyses were used in order to evaluate the test results. The strength and deformability of the rock mass corresponding to 32 selected sites were estimated. The Geological Strength Index, GSI and the Disturbance Factor, D were estimated in each site and used as input parameters. The values of mi, also used as input parameters, were those estimated by triaxial testing in the laboratory. Additionally, in order to evaluate the impact of the mechanical parameters of intact rock to the estimation of the strength and deformability of the rock mass, rock mass parameters were estimated using the mi values proposed by relevant bibliographical references. As a result of the comparison between the two methods,the remarkable usefulness of the laboratory testing, as a means of preliminary design as well as the considerable impact of the mechanical parameters of the rock material to the strength and deformability of the rock mass have been pointed out.

Closely jointed greywacke rock masses are widespread throughout both the North and South Islands of New Zealand and much of New Zealand's infrastructure is constructed upon greywacke rock masses. This thesis deals with determining the rock mass strength of unweathered closely jointed New Zealand greywacke rock masses. Currently, the estimation of rock mass strength and deformability is reasonably well predicted through the use of such empirical failure criteria as the Hoek-Brown failure criterion and empirical expressions to predict deformability. However, previous studies upon predicting the strength and deformability of unweathered closely jointed New Zealand greywacke rock masses has shown that existing empirical methods of determining strength and deformability are unsatisfactory. The problem with predicting rock mass strength and deformability moduli of New Zealand greywacke and the lack of adequate data to calibrate a failure criterion was the starting point for this work. The objective of this thesis was to increase the knowledge of intact and defect properties of closely jointed greywacke, develop reliable rock mass data with which to calibrate a failure criterion and improve the ability to estimate the rock mass strength of greywacke rock masses. A review of existing failure criteria for rock masses was conducted and of these criteria, the Hoek-Brown rock mass failure criteria was selected to calibrate to both the intact rock and rock mass failure data, because of its broad acceptance in the rock mechanics community. A database of greywacke properties was developed based on previous studies upon unweathered greywacke around New Zealand and is attached to the thesis as an Appendix. The database included descriptions of greywacke defect properties and mechanical properties of the intact rock and joints. From this database, inputs could be justified for numerical modelling and later analyses of failure criteria. Records from the construction archives of the Benmore and Aviemore hydroelectric power projects in the South Island of New Zealand were reviewed to obtain information and results from a series of shear tests carried out on unweathered closely jointed greywacke in the 1960s. Data on rock mass strength at failure and rock mass deformability were extracted from these records to assess the predictability of the failure criterion and deformability expressions. Problems experienced during the shear tests at the Aviemore dam site created doubt as to the actual rock mass strengths achieved at failure. The behaviour of these tests was studied using the finite difference code FLAC. The work was aimed at investigating the potential for transfer of shear force between the two concrete blocks sheared in each test and the impact shear force transfer had upon the likely normal stresses beneath each block at failure. The numerical modelling results indicated that a combination of preferential failure occurring in one direction, and doubt in the actual normal load applied to the concrete blocks during testing lead to premature failure in the blocks sheared upstream. The blocks sheared in the opposite direction failed at normal stresses that are reflective of the strength of an unweathered greywacke rock mass, but these results could be explained by failure occurring along defects therefore not satisfying the assumptions of homogeneity typically required of a rock mass failure criterion. The Hoek-Brown failure criterion for intact rock was investigated by fitting it to the largest intact greywacke datasets. For a full set of test data (i.e. including tensile data), the Mostyn & Douglas (2000) variant of the Hoek-Brown failure criterion gave the best fit for a full set of rock mass data. A multiple regression method was developed which improved the fitted curve to intact data in the tensile region and gave the best estimate of tensile strength if no existing lab results for tensile strength were available. These results suggest that the Hoek-Brown failure criterion is significantly limited in its applicability to intact NZ greywacke rock. Hoek-Brown input parameters different to those suggested by Hoek et al (2002) are recommended for using the Hoek-Brown failure criterion for intact NZ greywacke. For closely jointed NZ greywacke rock masses, the results from the shear tests at Aviemore and Benmore were separated into different GSI classes and Hoek-Brown envelopes fitted to the datasets by multiple regression. Revised expressions were proposed for each Hoek-Brown input parameter (mb, s, ab) as a function of the GSI. The resulting revised Hoek-Brown failure envelopes for NZ greywacke offer a significant improvement on the existing criterion used to predict the strength of NZ greywacke intact rock and rock masses. The differences in the behaviour of the reaction blocks that failed before the test blocks and the reduction in rock strength due to sliding along defects from that predicted could be reasoned from recorded observations and the behaviour of the concrete blocks during the shear tests. This study has clearly illustrated the need for continued research in this area. This includes (1) a means of assessing the role of defects upon the shear strength of closely jointed greywacke rock mass into a failure criterion, (2) further modelling of the in-situ shear tests by a discrete element procedure to expressly determine the role of the defect on failure, (3) more testing on rock masses to obtain more data to calibrate a rock mass failure criterion, and (4) more studies on predicting the strength of extremely disturbed rock masses.