soil water movement and recharge through sand at a semiarid site in new mexico a semiarid site near socorro new mexico has been instrumented with tensiometers and a neutron probe access tube to study soil water movement which may contribute to areal groundwater recharge under natural conditions during the period of record which extends from november 1982 through may 1984 annual precipitation was approximately 17 9 cm yr 1 below a depth of about 30 cm pressure head ranged from about 129 to 35 cm and moisture content varied between about 0 05 to 0 09 cm3cm 3 the vertical hydraulic gradient was slightly greater than unity and indicated downward soil water movement unsaturated hydraulic conductivity was determined in the field by the instantaneous profile method recharge was calculated from darcy s equation using in situ pressure head data below the root zone calculated hydraulic gradient and in situ hydraulic conductivity recharge was also calculated as being equal to the unsaturated hydraulic conductivity corresponding to in situ water content both approaches indicate that the annual recharge rate may be as much as about 3 7 cm yr 1 or about 20 of mean annual precipitation during this period of record

simulation and inversion of borehole temperature profiles in surrogate climates spatial distribution and surface coupling a heat conduction forward model driven by ground surface temperature from three 1000 year climate simulations with the state of the art echo g model has been used to simulate underground temperature perturbation profiles an inversion approach has been applied to reconstruct ground surface temperature histories from the simulated profiles and to compare them with the climate model temperatures results support the skill of borehole inversion methods to retrieve long term temperature trends and the robustness of using the present day borehole network for reconstructing sat variations

independence of geostatic stress from overconsolidation in some beaufort sea clays reply since 1982 extensive use has been made of the self bored pressuremeter in arctic offshore site investigations one finding of this work is that the in situ geostatic stress ratio k0 of beaufort sea clays is apparently unrelated to the overconsolidation ratio ocr the procedures and data to support this finding are documented and the finding is discussed in light of the present geological understanding for the area it is concluded that the independence of k0 from ocr may be quite widespread a finding that contradicts the widely held tenet regarding the existence of a single valued function relating k0 and ocr if k0 is regarded as important then it should be measured in situ key words self bored pressuremeter geostatic stress ratio k0 beaufort shelf geologic history overconsolidation ratio

coupling of vampers within iloveclim experiments during the lgm and last deglaciation the vampers vrije universiteit amsterdam permafrost snow model has been coupled within iloveclim an earth system model this advancement allows the thermal coupling between permafrost and climate to be examined from a millennial timescale using equilibrium experiments during the last glacial maximum 21 ka and transient experiments for the subsequent deglaciation period 21 11 ka it appears that the role of permafrost during both stable and transitional glacial interglacial climate periods is seasonal resulting in cooler summers and warmer winters by approximately 2 c maximum this conclusion reinforces the importance of including the active layer within climate models in addition the coupling of vampers also yields a simulation of transient permafrost conditions not only for estimating areal changes in extent but also total permafrost gain loss

is global warming affecting cave temperatures experimental and model data from a paradigmatic case study this research focuses on the mechanisms that transfer the variations in surface atmospheric temperature into caves to evaluate whether they record the warming trend of recent decades as a study case we use the data from a hall in postojna cave slovenia which was monitored from 2009 to 2013 the low frequency thermal variability of this cave chamber is dominated by the conduction of heat from the surface through the bedrock we implemented a thermal conduction model that reproduces low frequency thermal gradients similar to those measured in the cave at the 37 m depth of this chamber the model confirms that the bedrock is already recording the local expression of global warming with a delay of 20 25 years and predicts a cave warming during the coming decades with a mean rate of 0 015 0 004 c year 1 however because of the transfer of surface atmosphere thermal variability depends on the duration of the oscillations the thermal anomalies with periods 7 15 years in duration have delay times 10 years at the studied hall the inter annual variability of the surface atmospheric temperature is recorded in this cave hall although due to the different delay and amplitude attenuation that depends on the duration of the anomalies the cave temperature signal differs significantly from that at the surface as the depth of the cave is a major factor in thermal conduction this is a principal control on whether or not a cave has already recorded the onset of global warming

application of hyperbolic stress strain models for sandstone and shale to fold wavelength in the mexican ridges foldbelt abstract the mexican ridges foldbelt on the continental slope east of mexico has major folds with wavelengths averaging 7 km locally there are also small amplitude near surface folds with wavelengths of 2 km initial dominant wavelength is modelled by the finite element method using the hyperbolic stress strain relationship originally derived for soils hyperbolic stress strain models for sandstone and shale are calibrated using field porosity depth relationships for shale and laboratory one dimensional consolidation data for sand and clay effective tangent young s modulus calculated from hyperbolic stress strain models is generally higher for sandstones than for shales and for both rock types modulus increases substantially with depth the finite element models of dominant wavelength duplicate the two orders of folds observed in the mexican ridges and match their wavelengths in the models fold wavelength is nearly constant for large variations in both sandstone fraction in the folded section and pore pressure magnitude in the overpressured basal shale below the folded section but fold amplification is increased by high pore pressure in the basal shale and by high sandstone fraction in the folded section fold wavelength is affected more by depth distribution of high pore pressure than by pressure magnitude and on the lower continental slope where grain size may be smaller a thicker zone of high pressure would partly explain the modest downslope increase in fold wavelength

experimental studies in natural groundwater recharge dynamics assessment of recent advances in instrumentation abstract to quantify and model the natural groundwater recharge process two sites in south central kansas u s a were instrumented with various modern sensors and data microloggers the atmospheric boundary layer and the unsaturated and saturated soil zones were monitored as a unified regime data from the various sensors were collected using microloggers in combination with magnetic cassette tape graphical and digital recorders analog paper tape recorders and direct observations to evaluate and automate data collection and processing atmospheric sensors included an anemometer a tipping bucket raingage an air temperature thermistor a relative humidity probe a net radiometer and a barometric pressure transducer sensors in the unsaturated zone consisted of soil temperature thermocouples tensiometers coupled with pressure transducers and dial gages gypsum blocks and a neutron moisture probe operated by an observer the saturated zone sensors consisted of a water level pressure transducer a conventional float gage connected to a variable potentiometer soil thermocouples and a number of multiple depth piezometers evaluation of the operation of these sensors and recorders indicated that certain types of equipment such as pressure transducers are very sensitive to environmental conditions extraordinary steps had to be taken to protect some of the equipment whereas other equipment seemed to be reliable under all conditions based on such experiences a number of suggestions aimed at improving such investigations are outlined

in situ evaluation of k0 in eastern canada clays an approximate value of the horizontal effective stress in an overconsolidated clay deposit is often determined from an estimate of the effective stress ratio k0 using the equation it is also generally considered that the parameter is approximately equal to sin for evaluating k0 in sensitive clays of eastern canada a testing program has been initiated on three different sites representing a large range of overconsolidation ratios three different in situ devices were used the cambridge self boring pressuremeter the flat dilatometer and hydraulic fracturing the results show that the different techniques give essentially the same k0 values they also give k0 values larger than those expected with an parameter typically between 0 75 and 1 15 key words clay dilatometer horizontal stress hydraulic fracturing in situ tests self boring pressuremeter

climate from borehole data energy fluxes and temperatures since 1500 1 variations in the earth s surface energy balance are recorded in the ground as perturbations of the subsurface thermal regime here i apply singular value decomposition svd inversion methods to 826 temperature depth profiles distributed world wide in order to reconstruct ground surface temperature histories gsth and surface heat flux histories shfh from the temperature and heat flux anomalies detected in the shallow subsurface inversions yielded a mean ground surface temperature and surface heat flux histories for the earth s continents for the last 500 years results indicate that the global average ground temperature and ground heat flux have increased an average of 0 45 k and 18 0 mwm2 respectively over the last 200 years and 0 9 k in the last five centuries

a sea level curve for the canadian beaufort shelf radiocarbon dated peat and peaty clay samples from geotechnical boreholes in the canadian beaufort continental shelf have been used to reconstruct a late quaternary relative sea level rsl curve the samples were carefully selected and evaluated using palynological techniques to ensure that reasonable age error limits could be given to each sample the dated samples were then related to the local geological setting using seismic profiles to determine the environment of deposition the resulting data show a rise of 140 m in rsl since 27 000 years bp a minor lowering of rsl at some time between 20 000 and 10 000 years bp is inferred from acoustic data contributions from basin subsidence sediment loading and consolidation account for 35 m of the total rsl rise the rsl curve is interpreted in the light of recent models of the isostatic and eustatic responses of the earth s crust at the laurentide ice sheet margin ice may have been more extensive during the middle wisconsinan than previously thought a

k o ocr relationships in soil the relationships between k o and ocr are investigated for primary loading unloading reloading conditions the study reviews laboratory data from over 170 different soils and presents an approach common to clays silts and sands simple empirical methods for predicting k o for normally consolidated and overconsolidated soils are evaluated the validity of the methods is supported by statistical analyses on the basis of the findings only the effective stress friction angle o and prior stress history ocr and ocrmax are needed to predict approximate values of k o

deep soil temperature as proxy for surface air temperature in a coupled model simulation of the last thousand years 1 the relationship between terrestrial deep soil temperature tdst and surface temperature sat at interannual and centennial timescales has been investigated in a simulation of the last millennium with a three dimensional climate model driven by estimations of historical external forcing tdst is loosely related to borehole temperature profiles which have been recently used to reconstruct long term temperature trends in the last centuries recently questions about the validity of boreholes based reconstructions have been raised in the simulation at interannual time scales the connection between tdst and sat is stable being stronger in the summer half year than in the winter half year at long timescales annual tdsl is a good proxy for annual sat and their variations are almost indistinguishable from each other both tdsl and terrestrial sat overestimate the variations of global mean sat this may be a source for the disagreement between statistical reconstructions of global sat and terrestrial borehole measurements

contraction driven shear failure in compacting uncemented sediments shear failure in sediments is universally linked with active boundary conditions such as those imposed by tectonic stresses under conditions of no lateral strain and in the absence of tectonic stress soil mechanics theories predict a simple one dimensional compaction in which sediment particles displace vertically without shear failure during pressure diffusion conflicting with this theory shear failure planes are often found in sediments that formed under near horizontal burial conditions we investigated the effect of particle scale volume contraction as a potential cause of shear failure in uncemented particulate materials and found that loss of particle volume under confined conditions no external loading resulted in pronounced lateral stress reduction often reaching coulomb frictional failure conditions shear strain localization was analytically predicted and modeled numerically due entirely to volume loss at the grain scale we define this mode of internally driven shear failure as contractile to distinguish it from that caused by external loading and show that it can explain many natural fracture systems without invoking regional tectonics

north american climate of the last millennium underground temperatures and model comparison general circulation models gcms are currently able to provide physically consistent simulations of millennial climate variability in which estimations of external forcing factors are incorporated as boundary conditions climate reconstruction attempts to recover as faithfully as possible past climate variability using a variety of independent and climate sensitive sources of information by deriving strategies of comparison between gcm simulations and proxy data or directly recorded data such as subsurface thermal profiles the agreement between model and observations can be assessed thermal profiles obtained from the boreholes of north america were grouped into eight geographically discrete ensembles and averaged to form robust representative profiles the gridded output from the three distinct integrations of the gcm echo g were similarly averaged by region these simulated millennial paleoclimatic histories were then forward modeled to arrive at the subsurface thermal profiles that would result from the temperature trends at the surface these forward modeled profiles were then compared with the borehole average thermal anomaly profile in each region in most of the regions studied the externally forced runs from echo g are in better agreement with underground temperature anomalies than with the control run suggesting that boreholes are sensitive to external forcing not only do echo g simulations demonstrate better agreement with borehole data when considering variable external forcing factors but echo g also appears to broadly describe qualitative aspects of long term climatic trends at a regional scale

experience with measurement of horizontal geostatic stress in sand during cone penetration test profiling the incorporation of an additional transducer to cone penetrometers has recently been proposed at the university of california at berkeley the additional transducer is used to measure the horizontal stress on the friction sleeve this stress being related to the horizontal geostatic stress of the soil this type of cone is referred to as a horizontal stress cone hsc although it also incorporates a piezometric transducer the paper derives an algorithm for determination of horizontal geostatic stress from measurements made with an hsc in sand this step is a prerequisite to use of the data because of the disturbance caused by the cone during penetration some mathematical aspects of the algorithm and how these aspects constrain cone data evaluation are discussed it is possible at least in principle to determine the horizontal geostatic stress in sand by penetration testing with an hsc experience in applying the proposed algorithm to the data obtained in a hydraulically placed sand fill is described

analysis of instrumented sharp cone and pressuremeter tests in stiff sensitive clay the objective of this paper is to compare field test results obtained in a stiff sensitive clay from quebec using prebored instrumented sharp cone tests iscts with those deduced from prebored and self boring pressuremeter tests pmts and sbpmts respectively and vane shear tests vsts comparisons are also made with triaxial test results it is shown that undrained shear strengths su deduced from pmts and iscts are greatly overestimated with respect to the values inferred from sbpmts and vsts as for the shear modulus g the opposite is true these discrepancies are considered to arise from initial disturbance and unloading caused by drilling of pilot holes in the case of pmts and iscts interpretation problems may be also related to the existence of very high lateral pressures at rest in the clay deposit

yield states and stress strain relationships in a natural plastic clay reply natural clays are commonly anisotropic due to their mode of deposition and lightly overconsolidated because of a variety of subsequent geological processes they exhibit marked changes in stiffness when they yield yield stresses from individual tests can be generalized into a yield surface for the clay if displacements during loading are taken into account by calculating specific volumes v 1 e throughout the tests this paper describes tests on 76 mm diameter triaxial samples of natural plastic lake agassiz clay from winnipeg the samples were carefully trimmed reconsolidated to approximately their in situ stresses and loaded in stress controlled tests along various stress paths in p q stress space the tests produced well defined yield envelopes in p q p v and q v plots and in corresponding plots where the stresses were normalized with respect to the vertical preconsolidation pressure vc comparison of one dimensional yielding states with results from k0 triaxial tests that were continu

effective stress vane shear strength correction factor correlations a recent effective stress model of vane shear strength testing in soils can relate measured torques to vane shear strengths using theoretical analysis in terms of effective stress parameters the strength estimates are based on known in situ stresses and soil parameters derived from laboratory testing the model may be applied for example in obtaining theoretical estimates of conventional undrained vane shear strengths for comparison with field data and for use in stability analyses however the model incorporates a correction factor v analogous to bjerrum s field vane shear strength correction factor intended to compensate for pore pressure and shearing rate effects this correction factor must be evaluated before reliable torque or shear strength estimates can be made in any given case to facilitate this the paper presents correlations of v with both liquid limit and plasticity index based on world wide data from clays and silts the correlations are compared with independent data from norwegian clays

experimental studies in natural groundwater recharge dynamics the analysis of observed recharge events abstract the amounts and time distribution of groundwater recharge from precipitation over an approximately 19 month period were investigated at two instrumented sites in south central kansas precipitation and evapotranspiration sequences soil moisture profiles and storage changes water fluxes in the unsaturated zone and hydraulic gradients in the saturated zone at various depths soil temperatures water table hydrographs and water level changes in nearby wells clearly depict the recharge process antecedent moisture conditions and the thickness and nature of the unsaturated zone were found to be the major factors affecting recharge although the two instrumented sites are located in sand dune environments in areas characterized by shallow water table and subhumid continental climate a significant difference was observed in the estimated effective recharge the estimates ranged from less than 2 5 to approximately 154 mm at the two sites from february to june 1983 the main reasons for this large difference in recharge estimates were the greater thickness of the unsaturated zone and the lower moisture content in that zone resulting from lower precipitation and higher potential evapotranspiration for one of the sites effective recharge took place only during late winter and spring no summer or fall recharge was observed at either site during the observation period of this study

comparison of observed and general circulation model derived continental subsurface heat flux in the northern hemisphere received 8 september 2009 revised 9 february 2010 accepted 19 february 2010 published 18 june 2010 1 heat fluxes in the continental subsurface were estimated from general circulation model gcm simulations of the climate of the last millennium and compared to those obtained from subsurface geothermal data since gcms have bottom boundary conditions bbcs that are less than 10 m deep and thus may be thermodynamically restricted in the continental subsurface we used an idealized land surface model lsm with a very deep bbc to estimate the potential for realistic subsurface heat storage in the absence of bottom boundary constraints results indicate that there is good agreement between observed fluxes and gcm simulated fluxes for the 1780 1980 period when the gcm simulated temperatures are coupled to the lsm with deep bbc these results emphasize the importance of placing a deep bbc in gcm soil components for the proper simulation of the overall continental heat budget in addition the agreement between the lsm surface fluxes and the borehole temperature reconstructed fluxes lends additional support to the overall quality of the gcm echo g paleoclimatic simulations citation macdougall a h h beltrami j f gonzalez rouco m b stevens and e bourlon 2010 comparison of observed and general circulation model derived continental subsurface heat flux in the northern hemisphere j geophys res 115 d12109 doi 10 1029 2009jd013170

spatial patterns of ground heat gain in the northern hemisphere 1 variations in the earth s surface energy balance are recorded in the subsurface as perturbations of the steady state thermal field here we invert 558 temperature depth profiles in the northern hemisphere nh in order to estimate the energy balance history at the continental surface from heat flux anomalies in the subsurface the heat gain is spatially variable and does not appear to have been persistent for the last 200 years at all locations but overall continental areas have absorbed energy in the last 50 years results indicate a mean surface heat flux of 20 6 mwm 2 over the last 200 years the total heat absorbed by the ground is 4 8 1021j and 13 3 1021j for the last 50 and 200 years respectively we suggest that our results may be useful for state of the art general circulation model gcm validation and for land surface coupling schemes

determination of erosion thickness by numerical back analysis the case study of badenian clays in the carpathian foredeep czech republic abstract the paper describes an application of the geotechnical numerical back analysis in estimating the thickness of eroded sedimentary overburden in shallow basinal sediments the approach is based on the back analysis of the coefficient of earth pressure at rest k 0 and on estimating the unloading from the obtained k 0 value this approach is compared with the conventional methods represented by baldwin butler s compaction curves and casagrande s concept of preconsolidation stress the results of these two commonly used methods are incorrect if the sedimentary profile is affected by ageing effects such as cementation secondary compression etc the method is demonstrated on the lower miocene marine clay often called tegl which was deposited in the carpathian foredeep in the vicinity of brno czech republic the numerical back analysis was applied to galleries and adits opened during site investigation of the kralovo pole tunnels in brno the application of baldwin butler s equation suggested the erosion thickness of 180 270 m and casagrande s method of 100 800 m while the numerical back analysis of 0 40 m

assessment of self boring pressuremeter tests in sensitive clay the present paper analyzes field test results obtained by means of the cambridge self boring pressuremeter sbpm in a sensitive champlain clay of quebec it is shown that although the undrained shear strengths deduced from the sbpm tests are higher than the values obtained with the field vane the observed discrepancy is reduced by taking into account progressive failure effects it is not the sbpm test that overestimates the undrained shear strength but rather the vane test that underestimates it in this sensitive clay total and effective field stress paths are inferred from the sbpm tests and it is shown that the effective stress paths approach the tension zone of the mohr coulomb failure diagram before heading towards the large strain failure envelope of the clay the pressuremeter interpretation has been thoroughly worked through for various uncertainties like undrained test conditions plane strain conditions and disturbance basing the final judgment on a comparison of the effective stress adj

marine geotechnical engineering in canada marine geotechnical engineering in canada is over one hundred years old having started with overwater drilling and testing for bridges and nearshore structures its growth has been sporadic with not much attention being directed to the geotechnical properties of marine soils until the late 1970 s when design of artificial islands made up of large caissons started to develop for about the last 15 years marine geotechnical engineering has been driven by the oil and gas industry most of the action has been in the beaufort sea where complex site conditions have necessitated detailed geotechnical field drilling sampling programs and in situ testing very little geotechnical engineering research work or site invesigation has been carried out off the east coast except for the hibernia site on the grand banks in the coming years we can expect to see dramatic changes in site investigation methods the use of robotics and expert systems coupled with innovative geophysical techniques could dramatically change our methods of site charcterization and measurement of geotechnical properties

reconstruction of cave air temperature based on surface atmosphere temperature and vegetation changes implications for speleothem palaeoclimate records abstract cave temperature is a parameter of major importance for palaeoclimate studies based on speleothems since most proxies used are temperature dependent the general assumption that cave temperature reflects the mean annual surface atmosphere temperature sat over the cave is based on a limited number of specific studies and detailed mechanisms supporting this link are not properly described eagle cave in spain was used to understand the detailed mechanisms connecting sat and cave temperature a monitoring programme conducted from 2009 to 2011 allows the characterization of the thermal dynamics in the cave air in the studied karstic environment thermal conduction is the main mechanism responsible for transferring the ground temperature signal to the cave the calculated thermal diffusion coefficient is 0 756 10 6 0 013 m 2 s 1 the sat signal is recorded at the cave with a delay ranging from 3 to 11 yr depending on the thickness of the bedrock over the ceiling 5 18 m a cave cooling of 2 c has been recorded since mid 1970s when cave temperature measurements were made the application of a model exclusively based on thermal conduction of sat does not reproduce the observed thermal changes however vegetation cover over the cave was modified dramatically during recent decades this impacts ground temperature due to the changes in exposure to insolation and the modification of soil properties which is eventually recorded in the cave the incorporation of changes in vegetation cover in the model provides a realistic thermal reconstruction the impact of vegetation cover was much more significant than sat in order to explain the large thermal change in the cave over past decades thus the cooling in eagle cave during past decades is mainly controlled by a variable decoupling from mean annual sat as a result of the afforestation over the cave the effect of this thermal decoupling on speleothem 18 o records is potentially significant and should be considered when performing accurate palaeoclimate reconstructions

significance of localized pore pressures to the genesis of septarian concretions the burial stress and hydrologic conditions existing during concretion formation in mudrocks are evaluated and integrated into a model for the genesis of septarian cracks initial concretion cement formation will lower concretion permeability through the filling of pre existing pore space during progressive burial this may lead to increased excess pore pressure localized within the concretion body causing a reduction of the effective stress analysis of the stress conditions and crack morphology suggests that cracks in septarian concretions result from tensional failure sub critical crack growth as a consequence of this localized excess pore pressure conditions suitable for crack formation will depend upon the magnitude of the excess pore pressure and the stress corrosion limit of the concretion body a review of the likely strength of such concretions indicates that cracking could be initiated at depths less than 10 m a variety of observed crack morphologies can be explained with this model depending upon the spatial distribution of strength and effective stress in the concretion crack orientations mostly reflect stress anisotropy but are also influenced by directional anisotropy in the crack growth rates locally increased pore pressure also likely occurs in non septarian concretions but is not sufficient to cause cracking this enhanced local pressure may assist the crystal surface growth reactions of the carbonate cement through this enhancement process the shape of concretions may be a response to the local anisotropic pore pressure contours which reflect the permeability anisotropy of the concretion and surrounding mudrock

evaluation of soil state from sbp and cpt a case history the cone pressuremeter test cpt is widely used to determine the in situ state of cohesionless soils however although the cpt is simple inexpensive and accurate the subsequent interpretation

simulating heat transport of harmonic temperature signals in the earth s shallow subsurface lower boundary sensitivities across the bottom boundary at depths that usually range between 2 and 10 m boundary conditions at these depths however change the behavior of propagating temperature signals in a way that is not representative of the actual behavior in the earth s subsurface here we explore how the choice and depth of a lower boundary condition influences the subsequent evolution of subsurface temperatures given a simple harmonic surface temperature function 3 two studies that have investigated how the depth of the lower boundary condition affects subsurface temperature evolution are lynch stieglitz 1994 and sun and zhang 2004 lynch stieglitz 1994 investigated the behavior of annual signals in a land surface model with a zero flux lower boundary condition imposed at 2 3 m and noted that the annual signal was attenuated less and phase shifted more with depth than what was expected that is the model formulation yielded subsurface temperatures that were warmer in summer and colder in winter with maximums occurring later in the year than what was expected in realworld conditions sun and zhang 2004 provided an additional investigation of the finite boundary effect again focusing on the annual signal they demonstrated behavior similar to that noted by lynch stieglitz 1994 and concluded that land surface models should place lower boundaries between 6 and 15 m depending on the thermophysical properties of the modeled subsurface 4 both of the above mentioned studies used numerical land surface models to elucidate the impact of the lowerboundary condition on simulations of subsurface heat transport and focused only on the annual signal we take an alternative approach to this problem and employ analytic solutions of the one dimensional thermal diffusion equation this approach allows a more general and transparent understanding of how the depth of the lower boundary condition impacts simulations of heat transport across a wide range of frequencies

factors affecting at rest lateral stress in artificially cemented sands this paper presents the results of a laboratory study on the at rest lateral stress and ko of two artificially cemented sands a modified oedometer ring was used to measure the lateral stress of cemented and uncemented sands test materials were no 3 ottawa sand and a marine sand with portland cement the specimens were prepared using the method of undercompaction to minimize the influence of specimen preparation on test results the cement contents were 0 0 5 1 0 2 0 4 0 and 8 0 by the weight of dry sand the water content of the specimens was 4 of the weight of dry sand and cement when the sands were cured under zero confining pressure the test results indicated the following the at rest lateral stress in cemented sands decreases significantly with increasing cement content the relationship between the vertical and at rest lateral stress is nonlinear and the value of ko increases with increasing vertical stress and the lateral stress decreases with sand density and curing period when the s

in situ lateral stress measurement in glaciolacustrine seattle clay using the pressuremeter pressuremeter testing was conducted for the state route sr 99 bored tunnel project in seattle washington to estimate in situ soil stress deformation parameters along the tunnel alignment many of the tests were conducted in a very stiff to hard glaciolacustrine clay known as seattle clay this unit is historically known for deep seated slope failures and many of these failures have been attributed to the release of high locked in lateral stresses estimation in situ lateral stresses along the tunnel alignment was a primary focus of the exploration program due to the hard consistency of this unit and the potential for cobbles neither self boring pressuremeter nor dilatometer testing was feasible therefore prebored pressuremeter testing was used using several lateral stress estimation techniques including a novel in situ creep testing approach the in situ lateral stresses in the seattle clay were estimated to be significantly higher than what would be expected by assuming a simple laterally constrained vertical loading and unloading stress path due to glaciation deformational features commonly encountered in seattle clay indicate its stress history also has included significant lateral shearing the memory of this shearing within the fabric of the clay may influence the in situ stress state and response to lateral unloading