problems in identifying the effects of structure and critical state in a soil with a transitional behaviour this work shows that some soils with an intermediate behaviour between clays and sands do not have a unique compression line as has also been pointed out by martins et al it has been shown here that a unique critical state line could not be determined for the remoulded soil although the results shown here are for a reconstituted residual soil similar behaviour in compressibility has been found in silts and mixtures of sand and kaolin however it has been found that the critical state framework can be applied using a family of parallel critical state lines depending on the initial specific volume one of the questions raised by this work is how the effects of structure can be quantified if the intrinsic properties of the remoulded material are not unique the compression and critical state lines of the remoulded material are not only non unique but also of a distinctly different gradient from the natural material

effect of fabric on the behaviour of reservoir sandstones a laboratory investigation was undertaken on the mechanical behaviour of two sandstones that are commonly used as analogous hydrocarbon reservoir sandstones using triaxial apparatuses with a capacity of up to 70 mpa confining pressure both materials are lightly cemented but show a mechanical behaviour at large strains that is similar to that seen in rocks with much stronger cementation at small strains however these materials behave more like uncemented sands in that they show a strong stress dependency of the shear modulus and yield takes places at relatively small strains it is believed that fabric plays a fundamental role in the observed behaviour and this is supported by the experimental evidence so that the concept of strong fabric in sandstones is introduced

effects of relative density in progressive sliding of tailings deposits insights from flume tests abstract we present a series of flume tests to observe the process of tailings slope failure when subjected to a concentrated water flow progressive flow slides were observed in a range of tailing deposits with varying relative densities in which hydraulic conductivity reduced with increasing relative density slope densification by compaction of very loose or loose tailings deposits can lead to a lower permeability generating excess pore pressure and subsequently reducing slope stability this is evident from the great number of acoustic emission signals before sudden failure and from a sharp increase in the surface displacement and internal displacement observed after excess pore pressure generation the variation of fluid pressure distribution results in successive sliding onset at the toe and progressing from the toe to the rear of the slope excess pore pressure generation is found to occur after rather than prior to sliding and it only occurs along the slip surface an optimal relative density of 0 35 was identified in which the slope failure changes from a sudden collapse to a progressive failure however the optimal relative density may vary with the height of the slope this research extends existing knowledge about behavior of tailings materials while the observed discrepancy between the failure mechanisms of slopes made of loose and dense deposits could provide insights for preventing failures of tailings dams

effects of nonplastic fines on static liquefaction of sands des essais triaxiaux en compression non draines ont ete effectues sur des echantillons reconstitues de sable du nevada et d ottawa avec variation systematique de la teneur en fines particules inferieures a 0 074 mm afin d evaluer l effet de la fraction fine sur le potentiel de liquefaction statique lors d un chargement monotonique les fines etaient non plastiques les resultats indiquent clairement que la presence de fines peut augmenter considerablement le potentiel de liquefaction statique des quatre sables propres etudies lorsqu on utilise la technique du montage a sec avec un entonnoir les fines semblent creer dans le sol une structure particulaire tres compressible ce qui accroit ainsi le potentiel de liquefaction alors meme que la densite augmente accroitre la teneur en fines d un sable propre peut aboutir a l augmentation du potentiel de liquefaction jusqu a un seuil maximum pour lequel les fines dominent le comportement non draine du sol a ce point la le potentiel de liquefaction tend a devenir constant vis a vis de l indice de densite on a trouve que la liquefaction statique complete pouvait intervenir a un indice de densite superieur a 60 pour des teneurs en fines elevees

the mechanics of an italian silt an example of transitional behaviour by controlling the particle size distribution of an italian silt the influence of grading on its behaviour was investigated as the clay content was reduced the behaviour changed from a typical clay mode to a transitional form between that of clays and sands that had previously been seen only for gap graded soils emphasising that this type of behaviour is possibly much more extensive than previously thought the work has highlighted several features of transitional behaviour and in particular that unique normal compression and critical state lines do not exist that rendulic s principle does not apply and that drained and undrained tests do not reach unique ultimate states

transitional behaviors in well graded coarse granular soils abstractdrained triaxial compression tests were carried out for a well graded coarse granular soil cgs to investigate the effect of the initial specific volume on the location of the critical state line csl a family of parallel csls in the v logp plane was observed for the well graded cgs indicating that it exhibited transitional behavior the degree of transitional behavior was quantified from the relationship between the intercepts of the csls and the initial specific volumes giving a value of 0 59 which indicated a substantially transitional behavior the observations of the csl pattern in the cgs illustrated that transitional behavior could be extended to large sized granular soils beyond the usual transitional soils that have been observed so far which generally have gradings between those of clean sand and plastic clay

tectonics and magmatism in turkey and the surrounding area this volume contains 23 papers from a range of international contributors describing recent research into the tectonics and magmatism of turkey and its surroundings this region is sited at the collision zone between eurasia and afro arabia and as such provides an extraordinarily complete and well exposed record of the staged tectonic evolution of this sector of the alpine himalayan orogen the geological history of this area involves separation of continental fragments from the margin of gondwana their migration across the tethyan oceans the subsequent closure of these oceans and finally the development of the neotectonic regime which continues to evolve to the present day such a comprehensive record is relevant to the understanding of collisional zones worldwide the volume is divided into five sections tethyan evolution neotethyan ophiolites post tethyan basin evolution neotectonics and igneous activity the first two sections deal with tethyan oceans whose growth and subsequent closure dominated the geodynamic framework in the mesozoic and cenozoic the subsequent sections deal with more recent geological developments from the balkan peninsula in the west to the transcaucasus in the east that followed consumption of the tethyan oceans there is a broad mix of papers throughout the volume wide ranging review papers on ocean development and extensional tectonics are followed by detailed descriptions of petrology and geochemistry and geographically focused studies on basin evolution specific aspects of extensional and strike slip tectonics and discussions of the relationship of magmatic activity to the tectonic development of the area tectonics and magmatism in turkey and the surrounding area presents up to date results and ideas from a large number of international contributors on a wide range of current research activity in this region it is essential reading for all geoscientists with an interest in both academic and applied aspects of eastern mediterranean geology

revisiting the definition of the drag coefficient in the marine atmospheric boundary layer abstract a new functional form of the neutral drag coefficient for moderate to high wind speeds in the marine atmospheric boundary layer for a range of field measurements as reported in the literature is proposed this new form is found to describe a wide variety of measurements recorded in the open ocean coast fetch limited seas and lakes with almost one and the same set of parameters this is the result of a reanalysis of the definition of the drag coefficient in the marine boundary layer which finds that a constant is missing from the traditional definition of the drag coefficient the constant arises because the neutral friction velocity over water surfaces is not directly proportional to the 10 m wind speed a consequence of the transition to rough flow at low wind speeds within the rough flow regime the neutral friction velocity is linearly dependent on the 10 m wind speed consequently within this rough regime the new definition of the drag coefficient is not a function of the wind speed

forewarning of static liquefaction landslides abstractstatic liquefaction failure and the ensuing flow slide of slopes have produced significant damages to structures and even loss of lives based on a very large number 1 632 of laboratory s

on the critical state characteristics of methane hydrate bearing sediments abstract reasonable prediction of marine ground stability is vital for the safe exploitation of methane gas from the seabed and development of relevant technologies for gas production constitutive models based on a critical state soil mechanics framework for methane hydrate bearing sediments have been proposed in recent decades they required careful calibration of laboratory results to obtain accurate information on model parameters this study presents a comprehensive analysis of triaxial shear test data to examine the effects of hydrate saturation on the geomechanical characteristics of methane hydrate bearing sediments particularly at the critical state multiple critical state lines are identified for methane hydrate bearing sediments with different levels of hydrate saturation on the specific volume and logarithm of mean stress plane a rise in hydrate saturation shifts the critical state line of methane hydrate bearing sediments upward and slightly increases the gradient of critical state line in the v ln p plane non unique critical state lines are observed for methane hydrate bearing sediments under plane strain loading conditions considering methane hydrate saturation as an extra dimension of critical states the critical state line in the plane of specific volume and logarithm of mean stress becomes a three dimensional critical state surface

new data on the late cenozoic basaltic volcanism in syria applied to its origin abstract new data on geology and 21 k ar dates of the late oligocene quaternary basalts in syria combined with analysis of the new and previous data are used to reconstruct the volcanic history and relations between it and tectonic events volcanism began at the end of oligocene 26 24 ma and was concentrated in the late oligocene early miocene along a n trending band which stretches from the jebel arab harrat ash shaam up to kurd dagh and southern turkey activity waned in the middle miocene 17 12 ma but was resumed in the same band in the tortonian and increased in the messinian and early pliocene 6 3 4 ma when volcanism spread to the shin plateau and its coastal extension after a brief hiatus 4 3 5 ma volcanism became still more intensive and spread from the n trending band to the east into the northern margin of the mesopotamian foredeep and to the west into the dead sea transform zone additional eruptions continued into the holocene volcanism lasted 25 million years in the jebel arab highland and 15 million years in the aleppo plateau the long duration of volcanism in the same parts of the moving arabian plate and absence of records of one way migration of the activity mean that the magmatic sources moved together with the plate i e they were situated within the lithosphere mantle coincidence of the tectonic and volcanic stages of the arabian plate development proves that volcanic activity depended on the geodynamic situation caused by the plate motion situated within the lithosphere magmatic sources within this transverse band were possibly caused by thermal and deforming influences of the asthenospheric lateral flow moved laterally from the ethiopia afar deep superplume

influence of grading on the mechanical behaviour of stava tailings tailings dams can be fragile structures and too often they are subject to liquefaction the material they are composed of is rather peculiar having a man made origin and their behaviour is still not very well understood the soil from the stava tailings dams structures that were subject to liquefaction in 1985 causing extensive destruction was investigated in this study as an example of tailings two main aspects of their behaviour have been examined the influence of the percentage of silt and sand that compose the soil on its mechanical behaviour and the susceptibility to liquefaction analysing the behaviour within a critical state framework in this paper it is shown that as the quantity of silt increases the slope and intercept of the normal compression line and critical state line at higher pressures decrease until an inversion of behaviour is observed while at lower stress levels the critical state line changes its position but not its slope this means that the effect of adding silt on the

influence of fines on the collapse of loose sands a study has been carried out to investigate the influence of fines and gradation on the skeletal collapse behaviour of loosely prepared sand samples loose sand samples formed by moist tamping and consolidated to the same effective stress level were prepared with varying percentages of both plastic and non plastic fines 74 m samples were isotropically consolidated and subjected to monotonic undrained triaxial compression results indicate that increased percentages of fines 0 5 this change is represented by a decreased strain softening behaviour and a shifting of the steady state line variation of the gradation of the host sand appears to have little effect on the monotonic undrained behaviour a supplemental study involving use of the scanning electron microscope was carried out to evaluate the findings of the test program in terms of sand fabric key words colla

direct measurements of wind stress over the surf zone field data of the wind stress over surf zone waves are presented from an open ocean beach on the east australian coast two ultrasonic anemometers were deployed at nominal heights of 5 and 10 m above the water surface in the intertidal and inner surf zones with concurrent measurements of water levels and offshore wave parameters following a rigorous quality control procedure the wind stress was determined by the eddy correlation technique a constant stress layer was observed between 5 and 10 m elevation considering near neutral conditions only the wind drag coefficients were found to systematically change with the wind angle of approach relative to the shoreline and are much smaller for longshore wind than during onshore wind the concept of an apparent wave steepness changing with wind direction is suggested to explain this behavior the drag coefficients over the surf zone during onshore wind and near neutral conditions were determined to be almost twice the values expected at the same wind speed and open ocean conditions the observed charnock coefficient was similarly an order of magnitude larger than open ocean values a wave celerity of the order of that expected in the inner surf zone is required to explain the observed large roughness and drag coefficients using existing wave age dependent parameterizations this suggests that the slower wave celerity in the surf zone is an important contributor to the increased wind stress in addition to the sawtooth wave shape key points a new field data set of the wind stress over surf zone waves is presented concept of an apparent wave steepness is proposed to explain drag observations surf zone drag coefficients were almost twice the values outside the surf

ar ar dating of late cenozoic basaltic volcanism in northern syria implications for the history of incision by the river euphrates and uplift of the northern arabian platform 1 ar ar dating of basalt flows capping terrace deposits of the river euphrates in northern syria has provided a new quantitative chronology for the late cenozoic evolution of this important river system and for the associated history of surface uplift of the northern arabian platform through which it flows a region of relatively strong crust that has experienced only slow deformation notably fluvial deposits 65 m above the euphrates are overlain by basalt dated to 2717 20 ka those 45 m above the river are overlain by basalt dated to 2116 39 ka and those 8 9 m above the river are overlain by basalt dated to 402 11 ka these new dates require the previous dating scheme based on paleolithic archaeology to be revised the euphrates terrace deposits and the associated incised valley are much older than was previously thought rates of incision by the euphrates providing a proxy for regional surface uplift that is inferred to be the isostatic response to regional erosion have varied significantly over the past 3 ma with indications that between 1 2 and 0 9 ma there was regional subsidence which gave rise to fluvial aggradation this unusual pattern involving reversals in the sense of vertical crustal motions is interpreted to be a consequence of a relatively cold and thin mobile lower crustal layer no more than 5 km thick evidently due to the presence of a much thicker underlying layer of mafic underplating at the base of the crust this study thus indicates previously unsuspected complexity in the isostatic response to regional erosion in an area of high crustal stability

steady state concepts and static liquefaction of silty sands the results from an experimental study on silty sands are presented and evaluated in view of the framework of critical state or steady state soil mechanics drained and undrained compression tests were performed on nevada sand containing nonplastic silt the drained and undrained steady state lines diverged this divergence was caused by the tendency for static liquefaction at low pressures results from undrained tests with different initial void ratios produced different steady state lines unique steady state lines may therefore not always exist for silty sands denser specimens liquefied at low confining pressures while looser specimens at higher confining pressures showed stable behavior thus a unique relation between void ratio and confining pressure namely the steady state line may not represent the behavior of loose silty sands this occurs because silty sands exhibit reverse behavior characteristics more dilative behavior is observed with increasing confining pressure under undrained shearing load and deformation control testing was performed to evaluate the effect of strain rate compressibility was examined as an alternative measure of liquefaction potential

monotonic and cyclic liquefaction of very loose sands with high silt content the results from an experimental study on sands with high nonplastic silt content are presented drained and undrained triaxial compression tests undrained cyclic triaxial tests and drained undrained instability tests were performed on specimens of loose nevada sand with 40 silt content the behavior was observed to be somewhat different from previously published tests with sands at lower silt content the greater silt content appears to provide a more volumetrically contractive response throughout the entire stress strain curve however some aspects of the response were similar to sands with lower silt content monotonic undrained tests indicated reverse behavior i e static liquefaction occurred at low confining pressures and increasing dilatant volume change tendency was observed with increasing confining pressure analyzing the results using the concepts of steady state resulted in a unique steady state line only when undrained tests were sheared from the same isotropic compression line when

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

air water momentum flux observations over shoaling waves abstract this paper drab with simultaneous momentum flux observations from four towers placed at different depths along a shore normal line at the west end of lake ontario canada the towers were at nominal depths of 12 8 4 and 2 m in order to study the influence of shoaling waves on the air water momentum flux namely the effect of wave steepness and celerity on the aerodynamic roughness of the water surface analysis of the data have shown that the momentum fluxes cannot he explained by mean downwind speed alone u10 in contrast to open ocean experiments in which the wave maturity is generally near full development surface roughness z0 normalized on wave height was parameterized by both the inverse wave age u10 cp and the root mean square wave slope 0 with excellent correlation in each case r2 0 79 multiple regression using both the inverse wave age and the root mean square slope lead to the best results z0 2 26 u10 cp 1 82 3 83 r2 0 90 these findings are presented a

the dependence of sea surface roughness on the height and steepness of the waves it is proposed that the sea surface roughness zo can be predicted from the height and steepness of the waves zo hs a hs lp b where hs and lp are the significant wave height and peak wavelength for the combined sea and swell spectrum best estimates for the coefficients are a 1200 b 4 5 the proposed formula is shown to predict well the magnitude and behavior of the drag coefficient as observed in wave tanks lakes and the open ocean thus reconciling observations that previously had appeared disparate indeed the formula suggests that changes in roughness due to limited duration or fetch are of order 10 or less thus all deep water pure windseas regardless of fetch or duration extract momentum from the air at a rate similar to that predicted for a fully developed sea this is confirmed using published field data for a wide range of conditions over lakes and coastal seas only for field data corresponding to extremely young waves u10 cp 3 were there appreciable differences between the predicted and observed roughness values the latter being larger on average significant changes in roughness may be caused by shoaling or by swell a large increase in roughness is predicted for shoaling waves if the depth is less than about 0 2lp the presence of swell in the open ocean acts on average to significantly decrease the effective wave steepness and hence the mean roughness compared to that for a pure windsea thus the predicted open ocean roughness is at most wind speeds significantly less than is observed for pure wind waves on lakes only at high wind speeds such that the windsea dominates the swell do the mean open ocean values reach those for a fully developed sea

fetch and duration limited nature of surface wave growth inside tropical cyclones with applications to air sea exchange and remote sensing abstractthe 2d wavenumber spectra collected by an airborne scanning radar altimeter in hurricane hunter missions are used to investigate the fetch and duration limited nature of wave growth inside hurricanes despite the much more complex wind forcing conditions the dimensionless growth curves obtained with the wind wave triplets reference wind velocity significant wave height and dominant wave period inside hurricanes except near the eye region are comparable to the reference similarity counterparts constructed with the wind wave triplets collected in field experiments conducted under ideal quasi steady fetch limited conditions in dimensionless terms the youngest waves are in the back quarter of the hurricane in the northern hemisphere the dimensionless frequency decreases systematically counterclockwise ccw and the most mature waves are in the left hand sector except for those waves near the eye region the dominant wave phase speeds are about 0 32 to 0 71 times of the local wind speed

equivalent state theory for mixtures of sand with non plastic fines a dem investigation the discrete element method dem was used to simulate constant volume undrained triaxial compression tests for coarse particles sand mixed with non plastic fines simulations were performed on

reduction of wind stress due to swell at high wind conditions 1 wind stress over the ocean depends on the sea surface roughness which is determined by the sea state on one hand underdeveloped wind seas rougher than their fully developed counterpart increase the drag on the other hand the presence of swell can modify wind stress by modifying the wind sea roughness this latter mechanism is believed to have a great impact at high winds whenever underdeveloped local waves coexist with swell detailed measurements of wind stress and wavefield in fetch limited growth conditions were made in an area subjected to strong and persistent winds through the analysis of wavefield observations it is found that the presence of swell dampens the short wind waves the observed attenuation is greater for younger wind seas and decreases as the wind waves become older results obtained from modeling the interaction of wind waves and the air flow above point out that the attenuation of short wind waves causes a reduction of the wave supported stress which in turn decreases the total wind stress

the mechanics of cemented carbonate sands the behaviour of artificially cemented carbonate sand was investigated in triaxial tests at confining pressures of up to 9 mpa the results show that an important effect of cementing is a reduction in specific volume resulting from the increase in fines content this influences both the stress strain behaviour and the peak strength at strains beyond those required to fracture the cement bonding comparisons between the behaviour of cemented and uncemented soils should therefore be carried out on samples with the same gradings for cemented samples it is possible to identify a yield curve outside the state boundary surface of the uncemented soil a framework for the behaviour has been defined which depends on the relative magnitudes of the confining pressure and cement bond strength the behaviour of a natural cal carenite agreed well with this framework which is also likely to be applicable to other cemented soils le comportement d un sable carbonate artificiellement cimente a ete etudie a l aide d essa

identification and quantification of transitional modes of behaviour in sediments of venice lagoon an analysis was made of an extensive series of oedometer and triaxial tests on intact samples of silts and silty clays from the lagoon of venice as well as a more limited series of carefully controlled oedometer tests on reconstituted specimens the soils appear to have transitional modes of behaviour with compression curves that converge only slowly in the v log v plane and critical state lines defined for triaxial compression that are non unique in the v ln p plane two means of quantifying the degree of transitional behaviour are introduced one factor m being based on the oedometer data and the second p on the critical state data the values of m were in general lower than those of p because of the higher stress level considered the values of m were also found to depend on unloading which must be accounted for when comparing data from intact and reconstituted specimens

analysis of retrogressive loess flowslides in heifangtai china abstract the heifangtai terrace is located in the arid loess area in northwestern china where a large number of landslides was induced by agricultural irrigation on the terrace resulted in slope retreat at the terrace edge at an estimated rate of 0 024 km 2 yr 1 on the basis of field investigation and monitoring remote sensing and aerial images and laboratory tests we analyzed the characteristics of slope retreat and the failure mechanism of the loess flowslides the retreat of slope is caused by the retrogressive behavior of the loess flowslide of which new failure develops at the backwall of the preceding one the groundwater level variation governs the failure process and mechanism of the flowslides the observed loess flowslides were accompanied by rapid slope deformation high velocity and long runout distance exhibiting liquefaction and fluidization during the movement in the event of a loess flowslide a small scale drained slope failure produces a concave recession first intensifies localized groundwater flow on the slope surface while the flow is being impeded by the deposit which produces an undrained condition with increasing localized pore water pressure and in turn facilitates the subsequent flowslide results of the isotropically consolidated undrained triaxial tests icu and constant shear stress drained triaxial tests csd revealed the strain softening behavior in the saturated reconstituted loess and they showed that the excess pore water pressure is associated with a small axial displacement and possibly facilitated by some alternations in the loess structure at the micro scale

the mechanics of a saturated silty loess and implications for landslides the results from an intensive experimental investigation on a loess that was retrieved from a typical silty loess zone in the north western chinese loess plateau are presented and interpreted triaxial and oedometer tests were performed on intact and reconstituted samples in a saturated condition the soil behavior was found to be strongly affected by structure the compression paths of the intact samples crossed the intrinsic compression line of the reconstituted soil and reached well defined gross yield points after which the compression paths converged towards the intrinsic compression lines two critical state lines were defined for the intact and reconstituted soils in the volumetric plane as a result of a robust element of natural structure comparisons were made with a structured clayey loess retrieved from the south eastern loess plateau it was found that the effects of structure on the behavior of the two loess soils are similar though they are very different in natural properties this indicates that their natural structures might have experienced similar forming processes perhaps related to their common origin catastrophic flowslides commonly occur in the study area and the patterns of behavior observed in the laboratory tests may create some new insights into mechanisms of landslide initiation and subsequent movement as discussed in the study

wind and waves in extreme hurricanes waves breaking at the ocean surface are important to the dynamical chemical and biological processes at the air sea interface the traditional view is that the white capping and aero dynamical surface roughness increase with wind speed up to a limiting value this view is fundamental to hurricane forecasting and climate research but it has never been verified at extreme winds here we show with observations that at high wind speeds white caps remain constant and at still higher wind speeds are joined and increasingly dominated by streaks of foam and spray at surface wind speeds of 40 m s the streaks merge into a white out the roughness begins to decrease and a high velocity surface jet begins to develop the roughness reduces to virtually zero by 80 m s wind speed rendering the surface aero dynamically extremely smooth in the most intense part of extreme or major hurricanes wind speed 50 m s a preliminary assessment shows that cross swell dominant in large regions of hurricanes allows the roughness under high wind conditions to increase considerably before it reduces to the same low values

closure to transitional behaviors in well graded coarse granular soils by yang xiao m r coop hong liu hanlong liu and jingshan jiang

unsaturated soil mechanics in rainfall induced flow landslides abstract rainfall induced flow landslides in coarse grained soils pose significant threats to populations and structures due to their high velocities long travel distance and the absence of definite warning signs during the pre failure stage the triggering phase of these phenomena is frequently related to rainfall events which significantly reduce matric suction in the shallower soil layers in this paper the processes leading to the onset of such phenomena are illustrated and some observations on their modelling are briefly recalled the failure stage at different scales is then modelled with reference to a case study from southern italy which draws on high quality experimental data sets from extensive in situ and laboratory investigation

drained and undrained shear behavior of compacted coal wash abstractcoal wash is a granular waste material that is readily available in the vicinity of coal mining operations while its potential use in structural fills has been recognized in the past the effects of particle breakage on the geomechanical performance of the material have not been thoroughly investigated in this paper an experimental study on a selected coal wash is undertaken to characterize the influence of compaction and particle breakage on its corresponding stress strain behavior particular emphasis is given to the role of compaction energy level and associated breakage incurred during compaction on the drained and undrained shearing behavior the incidence of particle breakage for undrained and drained shearing was observed to be different which in turn had a strong influence in the yielding behavior and the critical state furthermore the critical state conditions for coal wash seem to be better described through a three dimensional surface incorporating the effect of breakage

kinematic evolution of the tethys belt from the atlantic ocean to the pamirs since the triassic abstract we present an updated series of kinematic reconstructions of the major plates around the tethys from the atlantic ocean to the pamirs between the early jurassic and the present this set is used elsewhere as a basis for paleogeographic maps of the entire region the problems related to the positions of the continents in the lower triassic are also discussed no direct analyses of magnetic anomalies and fracture zones in the atlantic have been made rather all available poles and rotations have been tested in order to eliminate or minimize possible kinematic errors the reconstructions are shown for nine key geological periods which correspond to well recognized magnetic anomalies except for the jurassic cretaceous boundary and the cretaceous tertiary boundary which correspond to interpolated positions paleolatitudes have been drawn using the study of westphal et al 1986 an attempt has been made to take into account the displacements caused by formation of the continental margins and basins by stretching the resulting relative vector of motions along the northern boundary of the tethys shows a significant change 80 m y ago left lateral motion with compression dominates before whereas right lateral motion with compression dominates after to the east rates of motion vary by a factor of three with time and four maxima can be clearly related to tectonic events in the late jurassic late cretaceous eocene and post middle miocene to the west north of apulia on the contrary the motion rate has not changed significantly since the early cretaceous and is close to 1 cm yr as an average these rather complex adjustments in rates and directions of relative motion are produced in great part through a complex migration of the africa eurasia pole of rotation and seem to be mostly governed by the tectonics of the tethys plate boundary

estimating slope of critical state line from cone penetration test an update estimation of density from cone penetration test cpt results is challenging as cone resistance is a function of a number of soil properties particularly compressibility while many of the relev

undrained behavior of sand fines mixtures and their state parameter abstractthe influence of fines on the undrained behavior of sand was investigated experimentally over a range of fines content and effective mean stress the role of fines on compressibility and formation of meta stable soil fabric was analyzed for a fines content in the range of 5 30 most of the specimens manifested reverse behavior opposed to the normal behavior of clean sand the addition of fines led to shifting of both the isotropic consolidation line and the steady state line increased compressibility and occurrence of reverse behavior all these behavior attributes are linked when the test results are interpreted in the context of the critical state soil mechanics framework in particular reverse behavior is associated with an isotropic consolidation line that locates above the steady state line several quantitative measures for characterizing the undrained deviator stress strain responses were proposed and these measures manifested correlation with the state parameter at the start of undra