instability conditions of loose sand in plane strain when a loose sand specimen is loaded under an undrained condition it may become unstable the instability conditions may be specified by an instability line determined using undrained tests however the instability behavior of sand has seldom been studied under plane strain conditions experimental data obtained under both triaxial and plane strain conditions are presented in this paper to define the instability conditions of loose sand under plane strain conditions using the state parameter a unified relationship can be established between the normalized slope of instability line and the state parameters for both axisymmetric and plane strain conditions using this relationship the instability conditions established under axisymmetric conditions can also be used for plane strain conditions

behaviour of clay fouled ballast under drained triaxial testing contamination or fouling of rail ballast with external fines including slurried and pumped subgrade material e g clay and silt is one of the primary reasons for track deterioration fouling causes differential settlement of the track and also decreases the load bearing capacity owing to the reduction in the friction angle of the granular assembly in certain circumstances fouled ballast needs to be cleaned or replaced to maintain the desired track stiffness load bearing capacity and track alignment all of which influence safety this paper presents and discusses the results of a series of large scale triaxial tests conducted on latite basalt a rail ballast of volcanic origin commonly used in australia consolidated drained triaxial tests were conducted under three different levels of confining pressure and varying degrees of clay fouling stress strain degradation characteristics are discussed in detail this paper also describes the non linear strength envelope and a novel empirical relations

an adaptive finite volume solver for ice sheets and glaciers 1 we have developed a new adaptive finite volume scheme for numerical simulations of ice sheets and glaciers the mathematical basis of the adaptive solver is represented by the finite volume method and irregular voronoi cell grids evaluation of spatial derivatives are obtained at cell edges from approximating the ice surface elevation locally by second order polynomials following a least squares approach the proposed scheme includes a simple and accurate method for handling discontinuities in ice thickness gradients along ice margins the flexibility of the voronoi cell structure allows for local mesh refinement in selected areas we show how increased mesh density along a steep ice margin may considerably increase overall numerical accuracy of an ice sheet simulation although the numerical scheme is not restricted to ice sheet representations using the shallow ice approximation sia we here use analytical sia solutions to test the accuracy of the method

undrained stress path of loose sand predicted from dry tests the constitutive properties of the soil skeleton of loose sand most relevant for predicting liquefaction flow slides are contraction and elastic compressibility they can be determined with dry triaxial tests a mathematical description of these idryi properties is presented and used to predict the specific stress path found in undrained triaxial tests a comparison between predicted and measured stress paths is discussed resume les propriotos de comportement du squelette de sable meuble les plus pertinentes pour prodire les couloes par liquofaction sont la contraction et la compessibilito olastique elles peuvent tre doterminoes par des essais triaxiaux secs une description mathomatique de ces propriotos sches est prosentoe et utilisoe pour prodire le cheminement de contraintes spocifique trouvo dans les essais triaxiaux une comparaison entre les cheminements mesuros et prodits est discutoe mots clos sable meuble liquofaction cheminement de contraintes non drainoes porosito mouilloe critique otat permanent traduit par la rodaction

detrital apatite fission track ages in middle jurassic strata at the rifted margin of w madagascar indicator for a protracted resedimentation history abstract the combination of litho and biostratigraphic data detrital apatite fission track ft ages and palaeocurrent data from jurassic sedimentary successions in the southern morondava basin sw madagascar suggests a resedimentation of the detrital material detrital apatite ft ages of middle jurassic sedimentary rocks range between 428 31 ma to 233 18 ma all apatite ft ages are older than their stratigraphic ages and become younger from top to the bottom of a middle jurassic profile such an apatite ft age distribution can be produced by a double inversion of the stratigraphic succession since the late carboniferous crustal extension between east africa and madagascar occurred the sampled material was initially deposited prior to the middle jurassic most probably during the karoo rifting latest carboniferous late triassic subsequently resedimentation occurred during a second sedimentation cycle which was probably connected to rift jump during the jurassic gondwana breakup and passive margin development between east africa and madagascar this study demonstrates that under certain temperature constraints detrital apatite ft age distributions combined with litho and biostratigraphic data can be used to verify sedimentation resedimentation events

maturity of central madagascar s landscape low temperature thermochronological constraints abstract low temperature thermochronological data from two profiles across central madagascar give apatite fission track and apatite u th he ages ranging between 258 ma and 176 ma and from 239 ma to 48 ma respectively thermal models derived from these data as well as modelling of basement denudation and the sedimentary record indicate that first order topography of central madagascar developed mainly due to flexural uplift during mesozoic times this was in response to successive erosion and depositional loading associated with the sedimentation in the morondava and majunga basins both of which are now exposed along the western margin of madagascar our data suggest that the eastern margin of the island had a similar denudation history and was probably at a similar topographic level before the late cretaceous break up of madagascar and the india seychelles block cretaceous normal faulting without major amounts of denudation led to the development of the present east coast topography defined by a tectonically juvenile escarpment in the centre of the island cenozoic tectonics and volcanism has had a minor and localised influence on the landscape of central madagascar

a note on earthquake induced liquefaction this technical note demonstrates that earthquake induced liquefaction consists of a cyclic instability dominated by heterogeneities in the soil and as such is a phenomenon that is fundamentally intractable analytically consequently it is shown that the liquefaction analyses proposed by the berkeley school are fundamentally incorrect not just after zero effective stress has been reached in the soil but well before that that is as soon as any pore pressure is generated and any softening of the soil takes place the method is fundamentally in error in assuming that dynamic stressing of the soil takes place independently of soil softening a distinction is also made between liquefaction failure and flowslides which is a phenomenon originally addressed by the harvard school in its studies of soil behaviour at densities looser than critical it is argued that the only way in which reliable design procedures against liquefaction can be developed is by the creation of empirical design criteria based on direct experimental data where possible this should involve experimentation at full scale which is by definition the most accurate method however such data is necessarily very limited and very expensive and so it is suggested that these design rules should be developed from the second most accurate experimental method namely centrifuge modelling and then calibrated wherever possible against measured full scale results it is also suggested that the most accurate form of in situ index testing of soil liquefaction potential will incorporate the self boring pressuremeter and some preliminatry recommendations are given in this note author trrl

a level set method for modeling the evolution of glacier geometry a level set method is proposed for modeling the evolution of a glacier surface subject to a prescribed mass balance this leads to a simple and versatile approach for computing the evolution of glaciers the description of vertical fronts and overriding phenomena presents no difficulties topological changes are handled naturally and steady state solutions can be calculated without integration over time a numerical algorithm is put forth as a means of solving the proposed model of glacier surface evolution it is evaluated by comparing different numerical solutions of the model with analytical and published numerical solutions the level set method appears to be a reliable approach for dealing with different glaciological problems

plate tectonics and the evolution of the british isles this paper is an essay on the rationalism and difficulties of the geological corollaries of plate tectonics with illustrations particularly from the geological history of the british isles there is special emphasis on the mechanics of continental lithosphere in extension when basins are formed and in convergence whereby continental lithosphere thinned in extension is shortened and restacked to form orogenic belts an upper lithosphere stress concentrating elastic lid suffers extremely complex inhomogeneous deformations above a simpler viscoelastic lower lithosphere whose deformation drives strain and displacement in the elastic lid the very nature of plate tectonics as relative motion among a multi plate mosaic of plates provides a rational semi quantitative framework for large scale geological complexity in space and time the caledonian and hercynian history of the british isles may be explained semi quantitatively in terms of plate boundary evolution but it is not possible to define unequivocal solutions the rationalism of plate tectonics is exhibited on a smaller more direct field scale by many of the complexities of ophiolite complexes such as ballantrae scotland that can be explained as the effects of the evolution of ridge ridge transforms and by diachronous deformation and sedimentation in subduction accretion prisms such as the southern uplands deformational and sedimentary patterns in nw europe from triassic times to the present day resulted from a complex interaction of extensional events related to diachronous atlantic opening and compressional events related to sequential alpine shortening phases those widespread events are typical of intracontinental plate boundary systems and create great difficulties for the geologist wishing to decipher relative plate motion from geological sequences because huge areas much larger than the british isles must be analysed and synthesized before much sense can be extracted further difficulties arise from the palinspastic and preservation problems of convergent boundaries orogenic shortening telescopes and partially subducts facies belts most orogenic belts were assembled as a collage of displaced and rotated terrain elements that were subsequently flattened elongated and straightened to an apparent but deceiving simplicity therefore while plate tectonics provides a rational geological framework against which for example british basin evolution can be tested and explained we cannot yet use the geological effects of plate boundary evolution to reconstruct relative plate motion quantitatively

undrained monotonic response of clean and silty sands a series of undrained monotonic triaxial compression tests were performed on ottawa sand containing 0 5 10 and 15 of non plastic silt the paper focuses on distinctive states of the monotonic undrained response of sands namely the critical state the phase transformation state the quasi steady state and the state of undrained instability onset of flow liquefaction specimens were prepared using slurry deposition and moist tamping to investigate the effect of the initial sand fabric on these states it was observed that an increase in the non plastic fines content leads to a downward shift of the critical state line in the void ratio mean effective stress space and to an increase of the critical state friction angle the present data suggest that the initial fabric of the sand appears to have a significant effect on the undrained behaviour in the early stages of shearing with its influence vanishing at large strains moist tamped specimens demonstrate considerably larger undrained instability s

the undrained cyclic behaviour of a carbonate sand a series of undrained cyclic triaxial tests was carried out on a carbonate sand that had previously been the subject of extensive research for monotonic loading it was found that the generation of

on estimating length fluctuations of glaciers caused by changes in climatic forcing the reaction of alpine glaciers to shifts in the equilibrium line altitude ela is calculated by using a two dimensional numerical model to solve the full equations for the velocity and stress fields full system model in the absence of basal motion rates of advance and retreat of the snout of typically sized alpine glaciers are found to be insensitive to the details of the flow at the snout even when the glaciers are far from steady state a comparison of results obtained with a full system model and a shallow ice approximation sia model yields no significant differences in advance or retreat rates this assumption has been implicitly made in numerous previous climatic studies and is here shown to be well justified using a realistic mass balance altitude feedback only slight model dependent changes in steady state lengths are found the relative importance of mass balance and glacier dynamics for the transient response of alpine glaciers to changes in the ela is given a precise meaning by determining the model dependent additional shifts in ela needed for the sia and the full system models to produce identical changes in length for alpine glaciers these additional shifts in ela are on the order of 10 m which is within the error range of ela estimates it follows that at least in the absence of significant basal motion there is no need to include the effects of horizontal stresses when calculating the reaction of alpine glaciers to climatic changes attention should focus on accurate determination of the mass balance distribution and model tuning to give realistic ice thickness distributions

an insight into the breakup of gondwana identifying events through low temperature thermochronology from the basement rocks of madagascar 1 fission track analysis was applied to the precambrian suites of madagascar in order to identify the lower temperature cooling histories and their relationships to the phanerozoic events that affected the island apatite ages range from 431 to 68 ma and zircon ages range from 452 to 238 ma thermochronologically the island can be divided into a southern central and northern region each with a subdivision on an east west basis the southern region is sharply separated from the central region by strongly contrasting apparent apatite ages over the northwest southeast striking ranotsara shear zone rsz the change in apparent ages over the rsz is indicative of later reactivation along younger brittle faults the central region has the oldest ages of the island and has a diffuse contact to the third region northward along the entire western margin of the precambrian basement initial paleozoic exhumation was followed by heating burial by sediments during jurassic and cretaceous times a decrease in ages along the eastern margin from 119 to 68 ma coincides with the predicted positions of the marion hot spot after effects of erosion are considered on the other hand these ages may represent progressive opening of the margin in a southward direction together with associated denudation of the rift shoulder the eastern part of the central region has remained very stable since at least devonian times undergoing only long term very slow exhumation at rates of 1 5 m myr

gpr and high resolution seismic integrated methods to understand the liquefaction phenomena in the mirabello village earthquake ml 5 9 2012 abstract we performed a geophysical survey in mirabello a village of emilia romagna region of northern italy to study the soil affected by the ml 5 9 earthquake of 2012 specifically the formation of surface ruptures by sand ejection due to the liquefaction of shallow subsurface layers the investigation was carried out using ground penetrating radar and seismic reflection refraction techniques this work confirms the importance of electromagnetic waves to map the shallow subsurface extent of fractures and liquefied sand bodies while the high resolution seismic reflection profile allowed us to map the fractures at depth the result obtained by tomographic inversion of first arrivals of seismic data has been compared with a ground penetrating radar section acquired in the same place furnishing complementary information for the interpretation of the section

interaction of an antecedent fluvial system with early normal fault growth implications for syn rift stratigraphy western corinth rift greece continental overfilled conditions during rift initiation are conventionally explained as due to low creation of accommodation compared with sediment supply alternatively sediment supply can be relatively high from the onset of rifting due to an antecedent drainage system the alluvial lower group of the western plio pleistocene corinth rift is used to investigate the interac tion of fluvial sedimentation with early rifting this rift was obliquely super imposed on the hellenide mountain belt from which it inherited a significant palaeorelief detailed sedimentary logging and mapping of the well exposed syn rift succession document the facies distributions palaeocurrents and stratigraphic architecture magnetostratigraphy and bios tratigraphy are used to date and correlate the alluvial succession across and between fault blocks from 3 2 to 1 8 ma a transverse low sinuosity braided river system flowed north north east to east across east west striking active fault blocks 4 to 7 km in width deposits evolved downstream from coarse alluvial conglomerates to fine grained lacustrine deposits over 15 to 30 km the length scale of facies belts is much greater than and thus not directly controlled by the width of the fault blocks at its termination the distribu tive river system built small stacked deltas into a shallow lake margin the presence of a major antecedent drainage system is supported by i a single major sediment entry point ii persistence of a main channel belt axis iii downstream fining at the scale of the rift basin the zones of maximum sub sidence on individual faults are aligned with the persistent fluvial axis sug gesting that sediment supply influenced normal fault growth instead of low accommodation rate during the early rift phase this study proposes that facies progradation can be controlled by continuous and high sediment sup ply from antecedent rivers

the liquefaction of sands a collapse surface approach recent large scale slides occurring during the hydraulic placement of an artificial island berm in the beaufort sea resulted from the liquefaction of the berm sand subsequent laboratory tests and

the separation of madagascar and africa identification of a sequence of east west trending magnetic anomalies of mesozoic age in the western somali basin helps define the position of madagascar in the gondwana reconstruction the anomalies are symmetric about ancient ridge segments and are flanked to the north and south by the jurassic magnetic quiet zone the motion of madagascar relative to africa was from the north and began in the middle jurassic about the same time as the initial breakup of gondwanaland sea floor spreading ceased when madagascar assumed its present position in the early cretaceous

specimen nonuniformities in water pluviated and moist tamped sands under undrained triaxial compression and extension x ray computed tomography ct methods and specialized triaxial equipment were developed to quantify void ratio distribution within saturated sand specimens reconstituted by water pluviation and moist tamping methods during undrained triaxial compression and extension the ct measurements were obtained at several points along the stress path of each specimen without significant removal of axial load it was observed that two reconstitution methods yielded very different void ratio distributions within specimens significant void ratio redistribution occurred within each specimen during the undrained shearing tests the influences of void ratio redistribution on globally observed specimen responses are discussed the findings of this research investigation provide unique insight into fundamental aspects of saturated sand behaviour during undrained triaxial shearing

reconstruction of madagascar and africa evidence from the davie fracture zone and western somali basin new seismic reflection gravity and magnetic data from offshore east africa allow the davie fracture zone to be traced from 11 s to its intersection with the kenyan coast at 2 s constraining the relative motion of madagascar and africa seasat derived free air gravity anomalies and slope rise positive magnetic anomalies observed in shipboard data help to locate the continent ocean boundaries cob off the shore of east africa and madagascar seismic reflection data further document a diapirprovince off madagascar presumably conjugate to that observed off kenya and somalia the dhow and very large crude carrier vlcc basement ridges are complex features and do not appear to be simple fracture zones owing their existence entirely to the separation of madagascar and africa from these data we determine a predrift fit of madagascar and africa involving a 14 2 rotation of madagascar to africa about a pole at 10 n 150 e the geometry of the reconstruction adheres to seismic and potential field data indicating the oceanic nature and extent of the comoros basin and of the somali basin between kenya and the seychelles and it does not conflict with onshore or offshore stratigraphy timing of the opening of the western somali basin is constrained by mesozoic marine magnetic anomalies and extrapolation to the interpreted cob and occurred between approximately 165 and 130 ma

predicting the onset of static liquefaction of loose sand with fines abstractloose sandy soil subject to undrained shearing manifests deviatoric strain softening and such a behavior has been referred to as collapse static liquefaction or instability this paper uses the term instability and characterizes its triggering by the corresponding effective stress ratio referred to as the instability ratio is to capture the influence of fines on is the state parameter as originally proposed by been and jefferies was generalized to an equivalent granular state parameter this is achieved simply by replacing the void ratio e with the equivalent granular void ratio e the conversion from e to e was achieved by a predictive approach and backanalysis is not required it was hypothesized that provided the fines content is less than the threshold value is and at the start of undrained shearing can be described by a single relationship irrespective of the fines content two published databases and a series of undrained triaxial tests results are used to eva

sedimentation in an intracratonic extensional basin the karoo of the central morondava basin madagascar the late carboniferous to triassic karoo supergroup of madagascar is a sequence of predominantly continental clastic sediments deposited during a long period of regional crustal extension in the morondava basin of western madagascar the lower two divisions of the karoo sediments the sakoa and the sakamena are deposits of fluvial and lacustrine sedimentation systems supplied from the precambrian metamorphic basement terrain to the east east west crustal extension produced a series of graben and half graben structures after the sakoa period which were reactivated after the sakamena the position and orientation of these half graben which were marginal to a larger rift system to the west were partly controlled by the steep nne ssw mylonitic fabric in the metamorphic basement palaeocurrents in the braided river deposits of the sakoa and lower sakamena indicate flow to the southwest and west in both sequences the rivers followed a regional palaeoslope to the southwest west and were apparently not significantly influenced by the local structural trends which were oriented perpendicular to this slope the absence of local structural control is attributed to extensive erosional events which followed each tectonic episode and preceded the onset of further sedimentation which took place on an essentially peneplained surface the tectonic episodes brought about changes in base level which caused this part of the basin to fluctuate between erosion and deposition

experiments on the flow behaviour of granular materials at high velocity in an open channel a series of laboratory flume experiments has been conducted to investigate the flow behaviour of dry sand at high velocities the first incentive for this experimental programme was an attempt to explain the high mobility of apparently dry masses of rapidly moving broken rock during rock avalanches sturzstroms test velocities of over 5 m s and most other parameters of the tests were found to be dimensionally similar to those for a typical rock avalanche yet the conclusion was negative even the most rapid of the experiments indicated flow behaviour which is in conformity with the constant volume uniform coulomb friction relationship as applicable to slow shearing this conclusion was confirmed independently both by direct measurements of base friction and mean density of the flows and by detailed observations of flow uniformity acceleration and velocity profiles the surprising mobility of st umlrzstroms therefore requires a different explanation une serie de tests a canaux a ete entreprise dans le

flow dynamics of tidewater glaciers a numerical modelling approach the dynamics of grounded tidewater glaciers is investigated with a time dependent numerical flow model which solves the full equations for the stress and velocity fields and includes a water pressure dependent sliding law the calving criterion implemented in the model shifts the calving front at each time step to the position where the frontal ice thickness exceeds flotation height by a prescribed value with this model the linear relation between calving rate and water depth proposed on empirical grounds is qualitatively reproduced for the situation of a slowly retreating or advancing terminus but not for situations of rapid changes length changes of tidewater glaciers i e especially rapid changes are dominantly controlled by the bed topography and are to a minor degree a direct reaction to a mass balance change thus accurate information on the near terminus bed topography is required for reliable prediction of the terminus changes due to climate changes the results also confirm the suggested cycles of slow advance and rapid retreat through a basal depression rapid changes in terminus positions preferably occur in places where the bed slopes upwards in the ice flow direction

influence of relative density on dilatancy of clayey sand fouled aggregates in large scale triaxial tests abstractthis paper presents an experimental investigation of the relative density on dilative behaviors of clayey sand fouled aggregates the large scale monotonic triaxial tests tx were conducted on mixtures in saturated conditions values of friction angles were compared with the dilatancy angles to stress the effect of the relative density on shear behaviors a correlation among the relative density peak friction angle the friction angle at the end of the test and peak stress based on triaxial tests was established the parameters of the correlation were determined the findings are expected to improve the understanding of the dilative behavior changes in character as the relative density changes

formation of the steer s head geometry of sedimentary basins by differential stretching of the crust and mantle if the lithospheric mantle is stretched over a wider region than the crust postrift stratigraphic onlap will occur at basin margins giving rise to a steer s head geometry space problems are avoided by making the total amount of extension in the lithospheric mantle equal to that in the crust the predicted pattern of onlap agrees well with that observed if the lithospheric mantle is stretched over a fractionally wider region than is the crust thus extensive stratigraphic onlap can be produced easily without recourse to sea level rise or flexural rigidity

considerations of the dilatancy angle in rocks and rock masses the present study responds to the poor treatment given to dilatancy in classical rock mechanics post failure problems such as tunnel or mine pillar design a comprehensive review of the literature and observations in regard to published test results would indicate that dilatancy is highly dependent both on the plasticity already experienced by the material and confining stress moreover it also appears that scale may play a non negligible role in our article we provide a detailed analysis of published test data with a view to proposing a sufficiently significant but conveniently simple formulation of the dilatancy angle that reflects these dependencies and that can be readily implemented in numerical codes the model is then tested demonstrating that it is capable of representing rock sample strain behaviour in compressive tests finally the model is applied to the resolution of ground reaction curves for tunnels in poor to average quality rock masses showing a good correlation with results obtained using practical rock engineering techniques r 2005 elsevier ltd all rights reserved

tectonic subsidence flexure and global changes of sea level tectonic models for the evolution of passive continental margins predict that following rifting sediments should progressively onlap basement at the edge of a margin as the lithosphere cools and increases its flexural rigidity with age the pattern of modelled onlap is strikingly similar to that used by vail and colleagues to estimate sea level rise through geological time this similarity suggests that major portions of stratigraphical sequences at margins may have a tectonic rather than eustatic control the patterns of onlap used by vail and colleagues may be widespread however because several widely separated passive margins rifted at similar times but they are unlikely to be worldwide

rainfall induced slope failure considering variability of soil properties both hydraulic properties and shear strength properties of unsaturated soils can affect the stability of a soil slope during a rainstorm the uncertainties of hydraulic property parameters for unsaturated soils and their effects on the reliability of slopes under rainfall condition have been studied recently chong et al 2000 tung chan 2003 for example chong et al 2000 studied the influences of the uncertainty of each parameter in the soil water characteristic curve swcc and the permeability function on the safety factor of unsaturated soil slopes using monte carlo simulations tung and chan 2003 performed probabilistic analyses of rainfall infiltration and slope stability considering uncertainties in swccs by the latin hypercube sampling technique in both studies the deterministic model used is an uncoupled seepage analysis program seep w geo slope ltd 2001a and a companion slope stability analysis program slope w geo slope ltd 2001b seep w is formulated for conditions of constant net normal stress and non deformable soil media however under real situations the seepage and flow processes in a deformable soil are influenced by soil deformations a coupled hydromechanical model is therefore preferred to analyse the behaviour and stability of a deformable soil slope subjected to rainfall the objectives of this paper are to develop a coupled hydromechanical model and a finite element based slope stability program to study the behaviour and stability of deformable unsaturated soil slopes and to illustrate their application in probabilistic study by an example of a hypothetical unsaturated soil slope considering the variability of soil properties a

influence of placement method on the in situ density of hydraulic sand fills the range of densities achievable by hydraulic placement of sand straddles the boundary between values giving acceptable potential performance and those giving unacceptable potential performance this has led to concerns over the safety of structures using hydraulic fills such as the artificial drilling islands in the canadian beaufort sea liquefaction failures of hydraulically placed sand have occurred at four or more of these islands until recently the factors affecting in situ density were little understood data obtained from several artificial islands are presented and these are used to demonstrate the overwhelming influence of method of placement on in situ density the possible reasons for this influence and the implications for design are discussed recommendations are made for research that together with conclusions drawn in the paper should allow hydraulic fills to be used with more confidence in the future key words sand hydraulic fill liquefaction cone penetration test

behavior of marine sand clay mixtures under static and cyclic triaxial shear in situ indian marine soils occur as mixtures of sand and clay in widely varying proportions their engineering behavior has not been comprehensively and systematically studied an experimental program on reconstituted indian marine soils having different proportions of sand and clay was undertaken the study comprised one dimensional consolidation tests and static and cyclic triaxial tests this paper presents the results of this study and offers an interpretation of the behavior based on effective void ratio evr a new parameter defined as the ratio of volume of voids to the volume of effective soil fraction experimental results indicate a roughly unique evr log vc relationship and normalizability of undrained static behavior some predictions from the stress history and normalized soil engineering properties shansep approach with evr as basis in close agreement with experimental data have been presented hence evr is proposed as an appropriate parameter for describing and predicting the behavi

the strength and dilatancy of sand the effects of stress path and loading direction in the triaxial test on strength and dilatancy of sand are investigated it is shown that the unique relationship observed between peak friction ang

soil stability and flow slides in unsaturated shallow slopes can saturation events trigger liquefaction processes this paper illustrates an application of the theory of material stability to the analysis of unsaturated slopes the main goal is to contribute to the understanding of rainfall induced flow slides

defining an appropriate steady state line for merriespruit gold tailings failure of the merriespruit gold tailings dam in 1994 in south africa was unusual in that never before had a gold tailings dam in south africa failed in such a catastrophic fashion conventional thinking was that gold tailings would always exhibit dilative characteristics upon loading primarily because of the method of deposition which allows significant consolidation to occur due to sun drying this paper demonstrates that the concept of a steady state line which separates dilative from contractive behaviour upon undrained loading is applicable to merriespruit tailings four particle size distributions of merriespruit tailings were tested to determine the influence of the percent finer than 75 m on the position of the steady state line the tailings with the greater percentage of fines gave a steady state line that plotted above all the others which translated to the requirement that a greater relative density was necessary to produce noncontractive behaviour than for the low fines tailings samples