seepage beneath water retaining structures founded on spatially random soil the effect of stochastic soil permeability on confined seepage beneath water retaining structures has been studied random field concepts for the generation of soil permeability properties with a fixed mean standard deviation and spatial correlation structure have been combined with finite element methods to perform monte carlo simulations of the seepage problem analyses have been performed for a dam with two cut off walls the results of parametric studies to gauge the effect of the standard deviation and correlation structure of the permeability on the output statistics relating to seepage quantities exit gradients and uplift pressures are presented in all cases comparison is made with results that would be achieved on a deterministic basis flow rates and other quantities are shown to be affected significantly by the standard deviation and the correlation structure of soil permeability l article etudie l influence de la permeabilite d un sol stochastique sur l infiltration confinee existant sous

three dimensional seismic modelling of crustal structure in the tesz region based on polonaise 97 data abstract this paper reports the results of 3 d tomographic modelling of crustal structure in the trans european suture zone region tesz of poland eastern germany and lithuania the data are the product of a large scale seismic experiment polonaise 97 which was carried out in 1997 this experiment was designed to provide some 3 d coverage the tesz forms the boundary between the precambrian crustal terranes of the east european craton eec and the younger phanerozoic terranes to the southwest the 3 d results generally confirm the earth models derived by earlier 2 d analyses but also add some important details as well as a 3 d perspective on the structure the velocity model obtained shows substantial horizontal variations of crustal structure across the study area seismic modelling shows low

upper crustal seismic structure of the mazury complex and mazowsze massif within east european craton in ne poland the large scale seismic experiment polonaise 97 polish lithospheric onsets an international seismic experiment was carried out in may 1997 in poland lithuania and germany its main purpose was to investigate the structure of the crust and the uppermost mantle in the region of the trans european suture zone tesz that lies between the east european craton eec and the palaeozoic platform this paper covers the interpretation of seismic data along the nw se trending 180 km long profile p5 located on the eec the recordings were of a high quality with seismic energy clearly visible along the whole profile we have not found waves refracted below the upper crust in first arrivals in the nw part of the profile we have delineated a high velocity body with the p wave velocity in the range of 6 5 6 75 km s in the upper crust it corresponds to the ketrzyn anorthosite massif within the mazury complex the mazowsze massif is rather uniformly characterized by p wave velocities 5 9 6 05 and 6 2 6 35 km s in two layers respectively sufficient s wave data were available to estimate the vp vs ratio as well as the poisson ratio being 1 80 0 277 in the high velocity body and 1 67 0 220 in the upper crust apart from the 2 d model along the profile results of 3 d modelling in the area of the p5 profile are presented using off line recordings we got p wave velocity field up to 8 km s below the p5 profile at the depth of about 40 km as well as horizontal extent of the high velocity body

regional and teleseismic events recorded across the tesz during polonaise 97 abstract 20 polish short period three component stations were continuously operating for three weeks during polonaise 97 in the contact zone between palaeozoic and precambrian platforms in poland the distances between seismometers were about 20 km and the digitization interval was 0 02 s besides the shots a few regional events from the lubin area and teleseismic events mainly from the se backazimuth were also recorded interpretation of traveltimes for p and s waves for regional events using a simplified lt 7 model of crustal structure for theoretical calculation allowed correction of their origin time the same model can also explain the traveltime residuals of p waves for teleseismic events the main features of the division of poland into two platforms by the teisseyre tornquist tectonic zone ttz is seen both in the shape of residuals of teleseismic phases and in the receiver function a passive seismic experiment made during polonaise 97 as a reconnaissance for future teleseismic tomography experiment tor 2 gave quite promising results however to make a traveltime tomography and receiver function analysis the duration of data acquisition should be about half a year

3 d modelling of the crustal s wave velocity structure from active source data application to the eastern alps and the bohemian massif summary here i present results from 3 d modelling of crustal s wave velocities in the eastern part of the eastern and southern alps and the southern part of the bohemian massif data were acquired between 2000 and 2003 during three large 3 d wide angle reflection and refraction experiments the surveys aimed at the p wave velocity structure of the crust and uppermost mantle and therefore only vertical component geophones were used nevertheless many shot gathers show strongs waves in particular refractions from the crust sg waves and reflections from the moho discontinuity sms waves compared to p wave arrivals the traveltimes of s waves can only be picked with a relatively large uncertainty furthermore approximately 80 per cent of the data represent crossline recordings on which it is more difficult to assign certain phases to the arrivals for these reasons i apply signal detection and stacking routines to put the 3 d data set to best possible use concerning the crust a smooth 3 d velocity model is based on refractions from within the crust sg whereas the crust mantle boundary is modelled by reflections sms from the moho discontinuity considering that the projects were designed for p wave studies the proposed methodology provides surprisingly detailed images s wave velocities and poisson s ratio correlate with tectonic units and show significant features in the upper crust a high poisson s ratio is observed in the moravian part of the bohemian massif in the southern alps and in the northern calcareous alps and their basement within the eastern alps the middle and lower crust are only covered in the moldanubian part of the bohemian massif where poisson s ratio is low this would favour a felsic composition the evaluation of sms waves is in accordance with previously proposed p wave velocity models which indicate a fragmentation into three crustal blocks in the centre of the eastern alps

numerical evaluation of land subsidence induced by groundwater pumping in shanghai to predict the future behavior of land subsidence in shanghai due to pumping of groundwater a numerical model is established in the proposed model groundwater flow in three dimensional conditions and soil deformation in one dimen sional conditions are calculated the model takes into account the multi aquifer aquitard hydrogeological condition of the soft deposit of shanghai the variation of the coefficient of compressibility and coefficient of hydraulic conductivity of the soils with the consolidation process are simulated relationships among land subsidence groundwater withdrawal volume and groundwater level are analyzed comparison between the measured value and calculated value shows that the model simulates the measured value fairly well the future of land subsidence behavior due to groundwater withdrawal is predicted and discussed via consideration of the variation of the following parameters in the future 30 years net withdrawn volume of groundwater pumping layer and pumping region resume un modele numerique est propose afin de predire le comportement futur d un affaissement de sol cause par le pompage de l eau souterraine a shanghai dans le modele propose l ecoulement de l eau souterraine en trois dimensions et la deformation du sol en une dimension sont calcules le modele considere la condition hydrogeologique multi aquifere aquitard du depot mou de shanghai les variations du coefficient de compressibilite et du coefficient de conductivite hy draulique des sols lors du processus de consolidation sont simulees les relations entre l affaissement du sol le volume de retrait de l eau souterraine et le niveau phreatique sont analysees des comparaisons entre les valeurs mesurees et calculees montrent que le modele peut simuler les valeurs mesurees relativement bien le comportement futur du sol en affaissement cause par le retrait de l eau souterraine est predit et discute en considerant les variations pour les prochains 30 ans pour les parametres suivants le volume net d eau souterraine retire la couche de pompage et la region de pompage mots cles pompage de l eau souterraine affaissement du sol ecoulement de l eau souterraine en trois dimensions consoli dation en une dimension prediction traduit par la redaction

searching for regional crustal velocity density relations with the use of 2 d gravity modelling central europe case in this paper we search for a reference relation between seismic p wave velocity v and density ref for the continental crust based on the results of modern seismic experiments we compiled 2 d seismic models into a network of four each about 1100 1400 km long continental scale seismic transects cutting all main tectonic units in central europe the moho depth about 52 km beneath the tesz in se poland to about 25 km beneath the pannonian basin and the crustal structure of this area are characterised by a large variation this structural variation provides an interesting basis for gravity studies and especially for analysing the difference of the density structure between two major tectonic provinces of distinctive age difference precambrian and phanerozoic the 2 d gravity modelling applied for crustal cross sections representing the regional structure based on a unified gravity anomaly map of the area allows for a stable determination of some general features of the regional reference velocity density relation for the continental crust in general three major seismo petrological types of rocks can be distinguished sediments crystalline crust and mantle in compacted sediments the reference velocity density relation is well described by the gardner or nafe drake model calculated gravity anomalies using unified velocity density relation for the whole crystalline crust well describe observed anomalies with an average difference of 14 mgal however calculated gravity anomalies using separated velocity density relations for the crystalline crust of precambrian and phanerozoic europe describe observed anomalies better than for the entire crust with an average difference 12 mgal the most important feature of these relations is the large differentiation of the derivative d ref dv in the crystalline crust being about 0 3 g s m4 for precambrian and about 0 1 g s m4 for the phanerozoic crystalline crust the modelling suggests a very small density value in the uppermost mantle 3 11 g cm3 below the younger area while for the older area it is 3 3 g cm3

dewatering induced subsidence during excavation in a shanghai soft deposit foundation dewatering has become a major cause of land subsidence in shanghai the burial depth of foundations in relation to geotechnical construction works is less than 75 m and the corresponding groundwater includes phreatic low pressure artesian and the first confined aquifers based on the geological and hydrogeological conditions beneath shanghai methods of dewatering may be divided into three modes and further five patterns according to the insertion depth of the dewatering retaining system the most common dewatering mode aims to reduce the water pressure in the confined aquifer by setting the dewatering wells inside the pit whilst the retaining walls are buried in the confined aquifer and partially cut off the confined aquifer layer to predict the settlement due to foundation dewatering numerical models are generally adopted which are similar to those used to predict land subsidence induced by regional groundwater withdrawal however since foundation dewatering is conducted along with the setting of retaining walls and foundation pit excavation which differs from regional groundwater withdrawal interactions between the retaining wall dewatering well the dewatering excavation and dewatering recharge are important factors affecting the analytical model since the grading of the shallow soil layers is different stratified settlement characteristics of the shallow soil strata and seepage erosion which results in additional deformation need to be given particular consideration

crustal and uppermost mantle s wave velocity below the east european craton in northern poland from the inversion of ambient noise records the p wave velocities vp within the east european craton in poland are well known through several seismic experiments which permitted to build a high resolution 3d model down to 60 km depth however these seismic data do not provide sufficient information about the s wave velocities vs for this reason this paper presents the values of lithospheric vs and p wave to s wave velocity ratios vp vs calculated from the ambient noise recorded during 2014 at 13 bb star seismic array 13 stations 78 midpoints located in northern poland the 3d vp model in the area of the array consists of six sedimentary layers having total thickness within 3 7 km and vp in the range 1 85 3 km s a three layer crystalline crust of total thickness 40 km and vp within 6 15 7 15 km s and the uppermost mantle where vp is about 8 25 km s the vs and vp vs values are calculated by the inversion of the surface wave dispersion curves extracted from the noise cross correlation between all the station pairs due to the strong velocity differences among the layers several modes are recognized in the 0 021 hz frequency band therefore multimodal monte carlo inversions are applied the calculated vs and vp vs values in the sedimentary cover range within 0 992 66 km s and 1 751 97 as expected in the upper crust the vs value 3 48 0 10 km s is very low compared to the starting value of 3 75 0 10 km s consequently the vp vs value is very large 1 81 0 03 to explain that the calculated values are compared with the ones for other old cratonic areas

lithospheric structure of the bohemian massif and adjacent variscan belt in central europe based on profile s01 from the sudetes 2003 experiment 1 the sudetes 2003 seismic experiment investigated the lithospheric structure of the eastern part of the variscan belt of central europe the key profile of this experiment s01 was 630 km long and extended southwestward from the margin of the east european craton across the trans european suture zone tesz and sudetes and across the bohemian massif that contains the active eger ohre rift which is an element of the european cenozoic rift system good quality first arrivals and later phases of refracted reflected p and s waves were interpreted using 2 d ray tracing techniques the derived seismic model shows large variations in the internal structure of the crust while the depth to the moho varies in the relatively narrow depth interval of 28 35 km except for the polish basin on the northeast end of the profile the sedimentary cover is thin the crystalline upper and middle crust with velocities of 5 9 6 4 km s 1 is about 20 km thick and the 7 10 km thick lower crust can be divided into three regions based on p wave velocities a low velocity region 6 5 6 6 km s 1 beneath eger rift and sudetes that is bounded on the southwest and northeast by regions of significantly higher velocity 6 8 7 1 km s 1 beneath the saxothuringian and moldanubian in the southwest and fore sudetic monocline and polish basin in the northeast high velocity bodies vp 6 5 km s 1 were delineated in the upper crust of the eger rift region the seismic structure along the s01 profile images a variscan orogenic wedge resting on the down warped margin of the plate margin containing the tesz this situation implies the northerly directed subduction of the rheic ocean that existed between the southern margin of the old red continent and the armorican terranes presently accreted into the variscan belt closure of this ocean produced the rheic suture between low velocity crust of the variscan orogenic wedge and higher velocity crust of the tesz

the mohorovicic discontinuity beneath the continental crust an overview of seismic constraints abstract the seismic signature of the moho from which geologic and tectonic evolution hypotheses are derived is to a large degree a result of the seismic methodology which has been used to obtain the image seismic data of different types passive source earthquake broad band recordings and controlled source seismic refraction densely recorded wide angle deep seismic reflection and normal incidence reflection using vibroseistm explosives or airguns have contributed to the description of the moho as a relatively complex transition zone of critical importance for the quality and resolution of the seismic image are the acquisition parameters used in the imaging experiments a variety of signatures have been obtained for the moho at different scales generally dependent upon bandwidth of the seismic source this variety prevents the development of a single universally applicable interpretation in this way source frequency content and source and sensor spacing determine the vertical and lateral resolution of the images respectively in most cases the different seismic probes provide complementary data that gives a fuller picture of the physical structure of the moho and its relationship to a petrologic crust mantle transition in regional seismic studies carried out using passive source recordings the moho is a relatively well defined structure with marked lateral continuity the characteristics of this boundary change depending on the geology and tectonic evolution of the targeted area refraction and wide angle studies suggest the moho to be often a relatively sharp velocity contrast whereas the moho in coincident high quality seismic reflection images is often seen as the abrupt downward decrease in seismic reflectivity the origin of the moho and its relation to the crust mantle boundary is probably better constrained by careful analysis of its internal details which can be complex and geographically varied unlike the oceanic moho which is formed in a relatively simple well understood process the continental moho can be subject to an extensive variety of tectonic processes making overarching conclusions about the continental moho difficult speaking very broadly 1 in orogenic belts still undergoing compression and active continental volcanic arcs the moho evolves with the mountain belt 2 in collapsed phanerozoic orogenic belts the moho under the collapse structure was formed during the collapse often by a combination of processes 3 in regions having experienced widespread basaltic volcanism the moho can result from underplated basalt and basaltic residuum in precambrian terranes the moho may be as ancient as the formation of the crust in others precambrian tectonic and magmatic processes have reset it we note that seismic reflection data in phanerosoic orogens as well as from precambrian cratonic terranes often show thrust type structures extending as deep as the moho and suggest that even where crust and mantle xenoliths provide similar age of formation dates the crust may be semi allochothonous

comparison in undrained shear strength between undisturbed and remolded ariake clays triaxial consolidation undrained shear tests are performed on both undisturbed and remolded ariake clays to investigate the undrained shear strength behavior when the applied confining stress is larger than the triaxial consolidation yield stress the strength envelopes expressed in the plot of undrained shear strength versus confining stress of both the undisturbed and the remolded ariake clays are straight lines through the origin the strength envelope of the remolded ariake clays lies above that of the undisturbed ariake clays when the applied confining stress is larger than the consolidation yield stress this difference is caused by the difference in water content between undisturbed and remolded states when the data obtained from triaxial consolidation undrained shear tests of both the undisturbed and the remolded ariake clays are plotted in the plot of undrained shear strength versus water content it is found that the undrained shear strength decreases uniquely with the increase in water content

evaluation of the blocking effect of retaining walls on groundwater seepage in aquifers with different insertion depths abstract in the design of a deep retaining wall it is necessary to consider the blocking effect on groundwater seepage of retaining walls in aquifers in this study both laboratory tests and numerical simulation with finite element method fem were adopted to investigate the blocking effect on groundwater seepage under different insertion depths of retaining wall in aquifer laboratory tests were conducted to analyze this blocking effect in an unconfined aquifer the test results indicate that the effective insertion depth ratio j of a retaining wall in shanghai aquifer sand is about 70 a three dimensional numerical model 3d fem was conducted to analyze the laboratory test results the fem results show that fem is a reliable method to analyze the blocking effect on groundwater seepage in an aquifer based on the same aforementioned procedure a 3d fem model is established to investigate the blocking effect in the confined aquifer in shanghai deposit both laboratory test and fem results show that drawdown of groundwater level decreases with an increase of the insertion depth ratio j of retaining structures in an aquifer the optimal value of j approximately 70 is achieved for retaining wall based on the synthetic results from laboratory test fem analysis and the equation of pujades et al for either unconfined aquifers or confined aquifers of shanghai

crustal structure below the polish basin is it composed of proximal terranes derived from baltica abstract the large scale seismic refraction and wide angle reflection experiment polonaise 97 together with lt 7 and ttz profiles carried out with the most modern techniques gave a high resolution of crustal structure of the trans european suture zone tesz in nw and central poland the results of seismic investigations show the presence of relatively low velocity rocks vp

statistical and hydro mechanical coupling analyses on groundwater drawdown and soil deformation caused by dewatering in a multi aquifer aquitard system abstract groundwater withdrawn in a multi aquifer aquitard system maas may cause vertical cross flow supplement and result in groundwater drawdown and soil deformation in both aquifers and aquitards this study investigates the responses of groundwater and deep soils to dewatering in the maas through statistical and numerical analyses field data of ten pumping tests conducted in the maas in shanghai urban area are collected and a statistical analysis for groundwater drawdown and ground settlement is performed field measurements indicate that the drawdowns are distributed linearly along radial distance in logarithmic coordinates however the ground settlements are disproportional to the drawdowns and show a trilinear distribution along the radial direction to examine the inconsistent distributions of the groundwater drawdown and the ground settlement representative dewatering models are developed numerically and solved explicitly by the coupled biot s three dimensional consolidation theory numerical results of dewatering in maas are compared to those obtained by a non coupling formula moreover effect of a micro confined aquifer on drawdown and soil deformation is discussed it is found that soil compression in each stratum is closely related to the decline of the pore pressure whilst small expansions are observed in early dewatering stages due to the hydro mechanical coupling effect the ground surface settlement near the pumping well obtained by the coupled numerical method is significantly smaller than that by the non coupling formula owing to horizontal and vertical cross flow supplement an additional aquifer embedded in aquitard above the pumping aquifer can relief both the groundwater drawdown and ground surface settlement significantly

responses of retaining wall and surrounding ground to pre excavation dewatering in an alternated multi aquifer aquitard system abstract pre excavation dewatering ped is an important construction stage in deep excavation field measurements show that retaining walls can develop obvious deflections during ped which has been rarely considered in the past the characteristics of ped induced wall deflection and the relationship of this deflection to surrounding ground deformation are still unclear in this study a ped test is simulated by a numerical model the model is verified by field observations and used to investigate the responses of retaining wall and surrounding ground to ped results indicate that the maximum wall defection hm and surface settlement vm can all reach centimeter level under common conditions of ped the ratio of vm to hm varies at the range of 0 45 0 67 wall and soil deformations will be more obvious if the soils within the dewatering depth hd have better permeability the relative positions between hd and strata i e aquifer or aquitard have great influence on the ped induced deformations if an aquifer appears below hd further increasing hd can induce a rapid growth of wall and soil deformations if thick aquitard appears below hd the deformation increments by further increasing hd are not apparent however once hd exceeds the center of the thick aquitard and reaches a thick confined aquifer the wall deflections and soil deformation zones behind the wall will enlarge significantly meanwhile a large bending moment in the retaining wall will arise around the bottom of the confined aquifer the designers should consider this condition and allocate enough steel rebars there preventing the appearance of wall cracks in the confined aquifer

crustal structure of the eastern alps and their foreland seismic model beneath the cel10 alp04 profile and tectonic implications summary the subject of this paper concerns the seismic modelling of the crustal structure in the transition zone from the bohemian massif across the molasse basin and the eastern alps to the southern alps mainly on the territory of austria the cel10 alp04 profile crosses the triple point of the european plate adriatic microplate and the recently identified pannonian fragment the seismic data along the presented profile originate from two large experiments celebration 2000 and alp 2002 the wavefield observed in the eastern alps is more complex than in the bohemian massif strong first arrivals pg are distinct up to 60 90 km offset and are characterized by large variations in apparent velocity and amplitude the contact between the molasse basin and the eastern alps represents a barrier for seismic waves midcrustal reflections pc are usually recorded at short distance intervals 20 50 km and are also characterized by variations in apparent velocity and amplitude the moho reflections are usually strong and well correlated while pn arrivals are only fragmentarily recorded detailed 2 d forward modelling of all refracted post critical and reflected phases identified in the correlation process was undertaken using a ray tracing technique the p wave velocity in the crystalline upper crust of the bohemian massif and molasse basin is about 6 15 km s 1 which is slightly higher than in the alpine area about 6 0 km s 1 below the northern accretionary wedge of the eastern alps low velocity sediments penetrate towards the southwest sw down to about 10 km depth in the middle crust of the alpine part a reflective zone was modelled by a lamellae structure with alternating high and low velocities and thicknesses of about 2 3 km the lower crust in this part of the model is more homogeneous with a velocity of about 6 9 km s 1 in the bohemian massif a high velocity hv body vp 7k m s 1 o f af ew kilometres thickness was delineated in the depth interval 18 23 km the crustal thickness along the cel10 alp04 profile changes from about 42 44 km in the sw alpine part to around 40 km in the central part of the profile molasse basin and 38 40 km in the ne bohemian massif the velocity in the uppermost mantle determined from pn wave traveltimes is about 8k m s 1 along the whole profile the interpretation of the seismic wavefield is supplemented by an existing 3 d p wave velocity model of the area main features derived by 2 d modelling low velocities beneath the accretionary wedge high velocities in the lower crust of the bohemian massif moho topography well correlate with the 3 d model furthermore the 3 d model allows assessing the lateral extent of significant features alongside the cel10 alp04 profile this area is affected by both collision and escape tectonics the high reflectivity zone

numerical study on the responses of groundwater and strata to pumping and recharge in a deep confined aquifer abstract groundwater drawdown and strata settlements induced by dewatering in confined aquifers can be relieved by artificial recharge in this study numerical simulations of a field multi well pumping recharge test in a deep confined aquifer are conducted to analyze the responses of groundwater and strata to pumping and recharge a three dimensional numerical model is developed in a finite difference software which considers the fluid mechanical interaction using the biot consolidation theory the predicted groundwater drawdown and ground settlements are compared to the measured data to confirm the validation of the numerical analysis of the pumping and recharge both numerical results and measured data indicate that the effect of recharge on controlling the groundwater drawdown and strata settlements correlates with the injection rate and well arrangements since the groundwater drawdown induced by pumping can be controlled by artificial recharge soil compression can be relieved by reducing the changes of effective stress of the soils consequently strata settlement induced by pumping can be relieved by artificial recharge and ground settlements can be eliminated if an appropriate injection rate and well arrangement are being determined moreover the changes of the pore pressure and seepage force induced by pumping and recharge will also result in significant horizontal deformations in the strata near the recharge wells

geological characteristics of strata in chongqing china and mitigation of the environmental impacts of tunneling induced geo hazards this study investigated the geological characteristics of strata in chongqing and the tunneling induced geo hazards therein the urban area of chongqing contains six syncline anticline pairs and is bounded by the huayingshan basement fault to the west and by the changshou zunyi basement fault to the east the bedrock containing sandstone and mudstone of the upper shaximiao formation resulting from middle triassic strata is occasionally outcropped during urbanization many valleys in chongqing require to be backfilled to create more flat ground thus the extent and thickness of the loose backfill layer varied from place to place while tunneling in chongqing the following geological characteristics may cause geo hazards 1 backfill with a loose structure poor gradation high permeability and large void ratio 2 highly or moderately weathered mudstone and sandstone that can easily become softened once subjected to groundwater seepage and 3 syncline folding containing perched water or confined fissure water the potential geo hazards include groundwater ingress ground surface settlement and strata collapse while tunneling within backfill synclines sandstone synclines or weak fractured rock significant amount of groundwater may be encountered thus leading to a high risk of groundwater ingress ground surface settlement can be triggered due to the disturbances of tunnel construction to the backfill or consolidation effect after groundwater ingress strata collapse can be caused by the blasting induced disturbances to poor surrounding geology or by inadequate overburden thickness or by an increase in the effective stress resulting from groundwater loss caused by leakage to mitigate the environmental impacts of the tunneling induced geo hazards a series of countermeasures that is advance geological drilling advance ground improvement including full face grouting and grouting of the surrounding geologic media and advance pipe umbrella use are proposed in this paper the results from a case study indicate that the proposed countermeasures can greatly decrease the ground surface settlement and amount of groundwater ingress during tunneling in chongqing verifying the effectiveness of the proposed countermeasures

analyses of leakage effect of waterproof curtain during excavation dewatering abstract the waterproof curtain that is used to block groundwater leaks occasionally during deep excavation and can have a harmful impact on the surroundings this study adopts a three dimensional 3d fluid solid coupled finite element model fem to analyze the impact due to a leakage in the waterproof curtain during excavation dewatering in the model both a user defined one dimensional leakage element and a solid leakage element are incorporated to simulate the leakage the leakage of the curtain in the soil is analysed by monitoring the variation in hydraulic conductivity the simulated results demonstrate that the leaking rate leaking volume groundwater drawdown and ground settlement are closely related to the hydraulic conductivity of the leakage point the results also show that the groundwater head outside the pit declines quickly when the leakage occurs but soil consolidation proceeds slowly in addition the characteristics of the soil that is adjacent to the leakage point also have a tangible effect on the groundwater head and ground settlement the hydraulic conductivity and deformation modulus of the soil has a significant effect on the ground settlement while the influence of the anisotropy of the soil is relatively low

crustal structure of the mid polish trough beneath the teisseyre tornquist zone seismic profile abstract a new seismic refraction and wide angle reflection experiment in the teisseyre tornquist zone ttz in poland was conducting during july 1993 as an international polish finnish german and swedish co operation the ttz profile running in an se nw direction was exactly located in the central part of the mid polish trough in the zone of maximum subsidence from upper permian to upper cretaceous 19 shot points were placed along the 450 km profile the interval between the shot points was about 25 km 31 explosions 90 to 1000 kg of dynamite were recorded in two deployments using 135 modern three component seismic stations with spacing of the recording sites of about 1 7 km in this area the depth of the consolidated basement with a velocity of about 5 7 5 8 km s is 5 to 12 km deep nevertheless the p wave velocity is very low vp

introduction geological and geophysical studies in the trans european suture zone the trans european suture zone tesz is the boundary between ancient precambrian lithosphere of the east european craton eec and the younger lithosphere beneath the latest neoproterozoic palaeozoic mobile belts of western europe the former is characterized by a thick crust c 45 km low heat flow and a tectono thermal age of about 3000 to 800 ma the latter by a thinner crust c 30 km higher heat flow and a tectonothermal age of 560 to 290 ma these contrasting types of crust were juxtaposed during the caledonian and variscan orogenic episodes the crystalline basement of the tesz is largely concealed by sedimentary basins controlled by the reactivation of structures within the suture zone during permian mesozoic extension and cenozoic inversion the pre permian evolution of the craton and the mobile belts and the location of the sutures is inferred from isolated outcrops hundreds of boreholes and geophysical evidence existing seismic data demonstrates that the tesz is rather narrow and has an expression at all levels of the lithosphere and deep into the asthenosphere teleseismic studies have demonstrated that the differences in the velocity structure of the asthenospheric and lithospheric mantle across the tesz persist to depths of c 400 km zielhus nolet 1994

laminated structure of the lower crust in the fore sudetic region in poland derived from seismic data abstract the results of seismic studies of the crust of the palaeozoic platform in the fore sudetic region southwestern poland are presented the structure of the sedimentary cover and the boundary of the consolidated basement were determined from refraction profiles of a total length of about 1500 km and from seismic velocity profiling in deep boreholes interpretation of data from deep seismic sounding and wide angle reflection studies provided information on the structure of the lower crust and the crust upper mantle transition zone the results of the first deep seismic sounding measurements by the near vertical profiling method with recordings up to 18 s are also reported in the region under study the sedimentary cover thickness ranges from 3 to about 13 km and the moho discontinuity depth is from 28 to 35 km in the sedimentary cover and in the lower crust strong structural and physical inhomogeneities were identified in the 23 34 km depth range layers of 1 3 km thickness of increased and decreased velocity alternate they have velocity contrasts of 0 4 0 7 km s 1 and are shown by intense sequences of reflected waves which are observed both in the wide angle reflection studies and in the near vertical profiles

groundwater control and stability in an excavation in magnesian limestone near sunderland ne england abstract a case history is presented of a 22 m deep excavation for a storm sewage pumping station in the very variable and water bearing upper magnesian limestone adjacent to the english northeast coast considerable effort was expended during several phases of ground investigation to try to characterise the rock in engineering terms prior to construction in addition to conventional double barrel cored drilling valuable data on the condition of the weathered dolomites and limestones and on the localised nature of groundwater inflows were obtained by examining coastal exposures and from two trial shafts and a heading constructed as advanced works on the incoming sewer these helped in predicting many of the difficulties that might need to be overcame during construction a full scale pumping test at the site of the excavation also determined the bulk permeability of the strata and led to the conclusion that preconstruction groundwater control measures would be needed a peripheral grout curtain and basal grout blanket were constructed by low pressure techniques and their combined efficacy was tested by further pumping tests in the event construction of the excavation was relatively trouble free and was accompanied by maximum groundwater inflows of about 8 l s 1 at full depth induced internal erosion of the weathered rock was minimal some difficulties were caused however by the presence of a zone of gash breccia in one corner of the excavation and by persistent minor instability in the overlying glacial till these were overcome by special support measures overall the rock mass was less weathered and more competent than predicted by the initial ground investigation the coastal exposures subsequent triple tube coring and the two trial shafts helped to give a more realistic indication of the actual ground conditions

barrier effect of underground structures on aquifers abstract impervious structures below the water table modify the natural groundwater flow in aquifers they act as barriers causing heads to rise upgradient and to fall downgradient we define the barrier effect as the increase in head loss across the barrier with respect to the natural conditions prior to construction we distinguish between regional the minimum head loss observed at long distances and local the maximum head loss observed close to the structure barrier effects we use numerical and analytical methods to derive semi empirical equations to quantify the two barrier effects for semi permeable partially penetrating or fully penetrating but finite in length and barriers with a by pass in confined aquifers the resulting equations depend on the barrier geometry and on the natural head gradient in the aquifer and they are easy to apply we test their validity at two construction sites obtaining excellent agreement between the computed and observed barrier effects

characteristics of groundwater seepage with cut off wall in gravel aquifer i field observations1 this paper presents a case history of the leakage behavior during dewatering tests in the gravel strata of an excavation pit of a metro station in hangzhou china the groundwater system at the tes

interpretation of increased deformation rate in aquifer iv due to groundwater pumping in shanghai shanghai is a typical example of a region in china suffering from severe land subsidence previous investigations have shown that land subsidence is strongly related to groundwater pumping in both the temporal and spatial domains a series of field investigations shows that the deformation rate of aquifer iv aqiv has increased contributing significantly to the total subsidence in shanghai to predict the deformation behavior of aqiv in shanghai due to groundwater pumping four different models have been applied in this study i a model based on groundwater flow theory ii an elastic model based on cauchy mechanics iii a creep model incorporated into cauchy mechanics and iv a recently proposed land subsidence model by budhu based on cosserat mechanics based on a number of assumptions budhu s concept was extended to consider the time dependent behavior of groundwater potential in aquifers and the consolidation behavior of overburdened aquitards the calculated results of aqiv s deformation we

lithospheric structure of the trans european suture zone along the ttz cel03 seismic transect from nw to se poland abstract the large scale celebration 2000 seismic experiment investigated the velocity structure of the crust and upper mantle between western portion of the east european craton eec and the eastern alps this area comprises the trans european suture zone the carpathian mountains the pannonian basin and the bohemian massif this experiment included 147 chemical shots recorded by 1230 seismic stations during two deployments good quality data along 16 main and a few additional profiles were recorded one of them profile cel03 was located in southeastern poland and was laid out as a prolongation of the ttz profile performed in 1993 this paper focuses on the joint interpretation of seismic data along the nw se trending ttz cel03 transect located in the central portion of the trans european suture zone first arrivals and later phases of waves reflected refracted in the crust and upper mantle were interpreted using two dimensional tomographic inversion and ray tracing techniques this modelling established a 2 d quasi 3 d p wave velocity lithospheric model four crustal units were identified along the transect from northwest to southeast thickness of the crust varies from 35 km in the pomeranian unit nw to 40 km in the kuiavian unit to 50 km in the radom ysogory unit and again to 43 km in the narol unit se the first two units are thought to be proximal terranes detached from the eec farther to the southeast and re accreted to the edge of the eec during the early palaeozoic the origin of the remaining two units is a matter of dispute they are either portions of the eec or other proximal terranes in the area of the polish basin first two units the p wave velocity is very low vp

environmental protection using dewatering technology in a deep confined aquifer beneath a shallow aquifer abstract this paper presents an innovative technology referred to as dual function well dfw which has been developed in order to reduce the construction costs of dewatering when excavation is conducted in an aquitard over a confined aquifer dfw technology is a method to lower both shallow groundwater and deep groundwater either separately or simultaneously using one well the dfw includes two or more independent screens corresponding to each aquifer and a valve is located between the screens inside a steel pipe when the valve is closed groundwater is pumped from the upper screen in the shallow aquifer when the valve is open groundwater is pumped from the screens in both the shallow and deep aquifers dfw technology is used to replace the traditional method involving two sets of wells in which the first set of wells pumps groundwater from the shallow aquifer and a second set pumps groundwater from the deep aquifer to investigate the effectiveness of dfw field pumping tests using a dfw were conducted and both groundwater head and settlement were monitored numerical simulation was adopted to simulate the results of the pumping tests comparison between the results from the dfw and from an ordinary mixing well indicates that the use of a dfw with the valve closed can reduce the pumping time from a deep aquifer and can reduce the ground settlement caused by dewatering the results indicate the dfw technology is feasible and effective

land subsidence by groundwater over exploitation from aquifers in tectonic valleys of central mexico a review abstract structurally controlled differential subsidence scds is the gradual sinking of the ground characterized by the development of a damage band terrain discontinuities and collapses aligned according to the strike of a controlling geological structure scds has been reported since the 1980s in several cities settled on tectonic valleys in central mexico although groundwater abstraction is the main trigger recent research efforts also point out a tectonic component as a driving force the monitoring and quantification of scds has been done through a variety of techniques such as extensometry gps and insar furthermore the associated hazards endangering the population are floods aquifer pollution cracking and housing collapse this paper presents a comprehensive review of the current state of scds allowing for the first time the standardization of its definition mechanisms and triggering factors additionally this helps to avoid misinterpretation in the cases of sinking produced by the mexico city subsidence type mcst and thus provides the elements for proper methodological study of scds finally the review includes future research directions that need to be improved in order to reduce the impact of the phenomenon

seismic structure of the palaeozoic platform along polonaise 97 profile p1 in northwestern poland abstract the deep seismic profile p1 was conducted in northwestern poland as part of the polonaise 97 project data acquisition involved 100 mobile seismographs which recorded seismic waves from 11 dispersed chemical controlled explosions along this 300 km long profile a variety of seismic modelling techniques were employed to derive a velocity model along the profile this model indicates that the mesozoic and palaeozoic sediments are 6 km thick in the northwest and 3 km thick in the southeast with the main thickness variation taking place in the palaeozoic succession an undulating basement surface indicates tectonic activity during deposition of the lower palaeozoic sequence the crust is 30 33 km thick along the profile thickening gradually to the southeast the p wave seismic velocities are low 1 down to a depth of 20 km along the whole profile which we interpret as evidence for their being of sedimentary or volcanic origin the lower crust has a high p wave velocity 6 7 7 5 km s 1 high vertical velocity gradient and strong ringing reflectivity the velocity of the sub moho mantle p n is high 8 2 km s 1 features similar to the ones below this profile have been interpreted for the area south of the caledonian deformation front in northern germany and southern denmark these similarities indicate that the crust between the southeastern north sea and poland has a common origin we therefore suggest that the deep crust beneath the profile is not of variscan origin despite its location south of the variscan deformation front we propose that variscan tectonism in the area was thin skinned while the deeper crust may originate from the caledonian microcontinent east avalonia or possibly from baltica

land subsidence due to groundwater drawdown in shanghai introduction shanghai is located on the deltaic deposit of the yangtze river as illustrated in fig 1 fig 2 shows the main geological strata the total thickness of the quaternary deposit is about 300 m shanghai geology office 1976 1979 excessive pumping of the groundwater caused compression of the quaternary deposit and subsidence in shanghai although several countermeasures including recharge of the groundwater have been adopted to mitigate the rate of subsidence up to the present the recorded cumulative subsidence has been 2 3 m in the central area of shanghai this subsidence has caused a lot of social problems the immediate problem is the increase in the possibility of flooding from 1981 to 1994 rainfall flooding occurred 22 times at a rate of almost twice per year liu 2001 the possibility of tidal flooding also increased from 1956 the height of the dike along the coast line was increased four times with the crest elevation rising from 5 m to 6 8 m other problems caused by the land subsidence are damage to the sewerage system road buildings and subway tunnels etc in shanghai the monitoring of land subsidence started in 1921 the history of land subsidence in the urban area of shanghai can be divided into two periods namely a rapid subsidence period 1921 1965 and a controlled period 1965 present zhang han 2002 however there has been a tendency for the subsidence rate to increase after 1990 in this paper the mechanism of land subsidence due to excessive pumping of groundwater is discussed first then the measured field data are presented and the relationship between groundwater pumping and land subsidence is discussed

systematic methodology for velocity dependent gravity modelling of density crustal cross sections using an optimization procedure the paper describes a new method of gravity modelling of the density cross section along a dss profile we propose a systematic procedure of gravity interpretation using structural information contained both in the velocity distribution of the seismic model and the geometry of its layers the procedure is based on the optimisation of the density parameters of the model the values of the parameters are limited by relationships between the seismic velocity and the density optimisation with inequalities the formulation of the method allows for discussion of the presence of isostasy and the distribution of compensating masses the discussion is very important for the considered crust lithosphere system the presented calculations are done for one carpathian profile cel01 the analysis of the properties of the fitting procedure provides the characteristic depth of subcrustal compensating density structures the position of crucial tectonic boundaries along the profiles locations of the crustal areas having exceptional lithology the regional density differences of subcrustal matter and the estimation of regional deviations from the isostatic equilibrium

geological and hydrogeological environment in tianjin with potential geohazards and groundwater control during excavation this paper discusses the geological and hydrogeological features of quaternary deposits in tianjin as well as the geohazards related to groundwater hydrology in this region the soft soil deposits comprising silt sand silty clay and clay are composed of four aquifer groups in the first aquifer group one phreatic aquifer and two confined aquifers have relationships with underground construction in the urban area these three aquifers are separated by two aquitards and collectively form a multi aquifer system during geotechnical construction potential geohazards present are related to the groundwater which include water in rushing quicksand and piping hazards to prevent the aforementioned geohazards dewatering is conducted however groundwater pumping may result in large settlements of the surrounding ground to reduce pumping induced settlement the dewatering waterproofing system has been adopted according to the characteristics of the subsoil excavation depth and the surrounding environment the dewatering system can be divided into five patterns in the first four patterns when pumping is conducted in the excavation pit the groundwater head in the adjacent aquifers outside the pit decreases due to the leakage effect of the aquitards located between the aquifers in the fifth pattern waterproof curtain has cut off the aquifers completely and dewatering in the pit cannot result in settlement around excavation pit to avoid geohazards related to groundwater hydrology countermeasures recommended include construction of an effective waterproof curtain selection of a reasonable excavation dewatering pattern and withdrawal of required groundwater

geological and hydrogeological environment in shanghai with geohazards to construction and maintenance of infrastructures shanghai administrative region sar is located on the deltaic deposit of the yangtze river the bed rock under sar is generally buried in the depth of 200 m to 300 m except for several massifs where the bed rock is exposed to the ground surface the quaternary deposit in shanghai is soft sediment the variation of palaeoclimate influenced the sea level and resulted in a very complicated sedimentary environment the quaternary deposit in sar is composed of an alternated multi aquifer aquitard system maas the groundwater system is composed of one artesian aquifer and five confined aquifer layers with very high groundwater pressure head the maas was formed mainly within the warm geological era updated to 2 6 million years ago between two aquifers there is an aquitard which is composed of soft clayey soil formed mainly within the cold era the aquitards are composed of very soft clayey silt with very high compressibility and humus content the humus material was transformed into methane gas under a long term geological process with the development of economy the infrastructures were or are being constructed in the top shallow soft clayey deposit aquifer i and aquifer ii in sar the following geohazards occurred or possibly occur during the construction and maintenance of infrastructures i quicksand and piping hazards ii pumping induced hazards and recharge cutoff hazards iii long term settlement due to the seasonal fluctuation of groundwater level and iv geohazards of methane gas

new evidence on deglacial climatic variability from an alpine lacustrine record in northwestern yunnan province southwestern china abstract new deglacial pollen and conifer stoma records from tiancai lake northwestern yunnan province southwestern china an alpine lake in the southwest monsoon region are presented in this study based on these records the lithology of core tcyl1 and pca analysis of pollen data between 21 and 11 5 ka bp calibrated 14 c years the deglacial vegetation and climate changes are discussed in detail the results show that tiancai lake was above the upper limit of picea abies forest a treeline in the study area between 21 and 11 5 ka bp and the climate was colder and drier than that of the holocene during this period eight significant vegetation changes are recorded that are considered to be responses to changing temperatures and variations in the southwest monsoon in southwestern china the heinrich event 1 h1 the bolling allerod warm period ba and the younger dryas cold event yd are all clearly detected in this record in addition this study finds that the initial late glacial warming in northwestern yunnan province was at 18 7 ka bp which is coincident with the climate records in monsoonal central asia the indian ocean the tropical and subtropical pacific ocean and antarctica and is a response to solar insolation changes a noted temperature increase between 15 8 and 14 4 ka bp occurred at the end of the h1 and before the ba which indicates a strong pre bolling warming based on the study we consider that the hypothesis about a slowdown of the ocean s thermohaline circulation is sufficient to explain these late glacial abrupt events

geological formation and geo hazards during subway construction in guangzhou this paper summarises the stratigraphy tectonic structure geomorphology hydrogeology and engineering geology in guangzhou china and analyses the relevant geo hazards and countermeasures during subway construction the ages of the geological materials found in guangzhou range from the proterozoic era to the cenozoic era the bedrock is generally made up of sedimentary rock and weathered granite strata covered by soil with a thickness ranging from 2 to 20 m the presence of underground karst caves active faults and fissure water together with high piezometric levels leads to difficulties in shield tunnelling in guangzhou a case history where two tunnels and one subway station on the guangzhou metro line 7 were constructed is referred to in order to analyse the mechanism between geological formations and geo hazards three potential geo hazards are listed 1 water ingress and strata erosion 2 ground surface settlement and 3 sinkholes and their implications for shield tunnelling in guangzhou are summarised and discussed to mitigate the risk of these geo hazards a series of countermeasures comprising 1 optimising tbm cutting tool design and tunnelling parameters 2 grouting to enhance watertightness and stiffness of strata and 3 injecting bentonite slurry and foam into the head chamber are recommended in this paper

evaluation of the effectiveness of an alternative to control groundwater inflow during a deep excavation into confined aquifers this paper presents a case study of groundwater control for a deep excavation into confined aquifers in fuzhou china field pumping tests were first carried out prior to the excavation to investigate the groundwater conditions at the site and as well as to evaluate the feasibility of previous designed dewatering systems 34 m diaphragm walls together with pumping wells the results showed that under the condition of previous dewatering systems it would have been extremely difficult to safely lower the water level inside the excavation a co working scenario of partially penetrating curtains and horizontal waterproof curtain with jet grouting was then proposed to control groundwater inflows additional water tightness assessment tests wat were then performed that allowed to confirm the efficiency of the proposed method from the feedbacks of wat this proposed scenario not only successfully lowered the water lever inside the excavation below the excavation bottom maximum drawdown up to 14 9 m but also it minimized the drawdown outside the excavation less than 0 2 m furthermore an approach was proposed to approximately estimate the hydraulic conductivity of the jet grouting at the real site from the result of wat the hydraulic conductivity of jet grouted soil is three orders of magnitude lower than that of the original sediments

three dimensional seismic refraction tomography a comparison of two methods applied to data from the faeroe basin this paper presents a comparison of two tomographic methods for determining three dimensional 3 d velocity structure from first arrival travel time data the first method is backprojection in which travel time residuals are distributed along their ray paths independently of all other rays the second method is regularized inversion in which a combination of data misfit and model roughness is minimized to provide the smoothest model appropriate for the data errors both methods are nonlinear in that a starting model is required and new ray paths are calculated at each iteration travel times are calculated using an efficient implementation of an existing method for solving the eikonal equation by finite differencing both inverse methods are applied to 3 d ocean bottom seismometer obs data collected in 1993 over the faeroe basin consisting of 53 479 travel times recorded at 29 obss this is one of the most densely spaced large scale 3 d seismic refraction experiments to date different starting models and values for the free parameters of each tomographic method are tested a new form of backprojection that converges more rapidly than similar methods compares favorably with regularized inversion but the latter method provides a simpler model for little additional computational expense when applied to the faeroe basin data bounds on two model features are assessed using regularized inversion with combined smoothness and flatness constraints an inversion of synthetic data corresponding to 100 data recovery from the real experiment shows a marked improvement in lateral resolution at deeper depths and demonstrates the potential of currently feasible 3 d refraction experiments to provide well resolved long wavelength velocity models the similarity of the final models derived from the two tomographic methods suggests that the results from the new form of backprojection can be relied on when limited computational resources rule out regularized inversion

application of grey theory based model to prediction of land subsidence due to engineering environment in shanghai land subsidence is a common geological hazard the long term accumulation of land subsidence in shanghai has caused economic loss to the city since the 1990s the engineering structures have become a new cause of land subsidence many factors affect the process of land subsidence although such a process cannot be explicitly expressed by a mathematical formula it is not a black box whose internal structure parameters and characteristics are unknown therefore the grey theory can be applied to the prediction of land subsidence and provides useful information for the control of land subsidence in this paper a grey model gm gm 1 1 with unequal time intervals was used to predict the subsidence of a high rise building in the lujiazui area of shanghai and the results were compared with the monitored data the prediction of subsidence was also corroborated by laboratory tests and the results were compared with measured data and the predicted data by the adaptive neuro fuzzy inference system anfis it is found that the gm 1 1 with unequal time intervals is accurate and feasible for the prediction of land subsidence

evaluation of optimized depth of waterproof curtain to mitigate negative impacts during dewatering abstract dewatering using a combination of waterproof curtain and pumping wells is commonly adopted to ensure the stability of foundation pits in multi aquifer strata however dewatering is likely to result in environmental problems this paper investigates the impact on surroundings owing to the interaction between the waterproof curtain and pumping wells by numerical simulation the depth of the diaphragm wall penetrating the dewatering aquifer d and the filter length of pumping wells l are varied in the simulation the relationship between approximate hydraulic gradient i or ground settlement outside the foundation pit s with curtain depth ratio rd d over the thickness of the dewatering confined aquifer ha or filter length ratio rl l ha can be divided into three change parts namely initial gradual middle sharp and final gentle part three values of rd and rl namely effective suggested and control value are proposed rd and rl should vary between the effective and control value the suggested value of rd and rl is recommended in actual engineering by comprehensive consideration the effective suggested and control value of rd can be calculated by a linear equation according to the value of rl

the moho depth map of the european plate summary the european plate has a 4 5 gy long and complex tectonic history this is reflected in the present day large scale crustal structures a new digital moho depth map is compiled from more than 250 data sets of individual seismic profiles 3 d models obtained by body and surface waves receiver function results and maps of seismic and or gravity data compilations we have compiled the first digital high resolution map of the moho depth for the whole european plate extending from the mid atlantic ridge in the west to the ural mountains in the east and from the mediterranean sea in the south to the barents sea and spitsbergen in the arctic in the north in general three large domains within the european plate crust are visible the oldest archean and proterozoic crust has a thickness of 40 60 km the continental variscan and alpine crust has a thickness of 20 40 km and the youngest oceanic atlantic crust has a thickness of 10 20 km

lithospheric structure beneath trans carpathian transect from precambrian platform to pannonian basin celebration 2000 seismic profile cel05 1 in 2000 a consortium of european and north american institutions completed a huge active source seismic experiment focused on central europe the central european lithospheric experiment based on refraction or celebration 2000 this experiment primarily consisted of a network of seismic refraction profiles that extended from the east european craton along and across the trans european suture zone region in poland to the bohemian massif and through the carpathians and eastern alps to the pannonian basin the longest profile cel05 1420 km is the focus of this paper the resulting two dimensional tomographic and ray tracing models show strong variations in crustal and lower lithospheric structure clear crustal thickening from the pannonian basin 24 25 km thick to the trans european suture zone region 50 km together with the configuration of the lower lithospheric reflectors suggests northward subduction of mantle underlying carpathian pannonian plate under the european plate this however conflicts with strong geological evidence for southward subduction and we present three tectonic models that are to not totally mutually exclusive to explain the lithospheric structure of the area 1 northward old subduction of the pannonian lithosphere under the east european craton in the jurassic lower cretaceous 2 a collisional zone containing a crocodile structure where carpatho pannonian upper crust is obducting over the crystalline crust of the east european craton and the carpathian pannonian mantle lithosphere is underthrusting cratonic lower crust and 3 lithosphere thinning due to the effects of neogene extension and heating with the slab associated with young subduction southward in the miocene having been either detached and or rolled back to the east in the last case the northwestward dipping in the lithosphere can be interpreted as being due to isotherms that could represent the lithosphere asthenosphere boundary in the pannonian region

protection of neighbour buildings due to construction of shield tunnel in mixed ground with sand over weathered granite in south china many geological formations are composed of weathered rock covered by a thin layer of quaternary soft deposits e g clayey soil or sandy soil when the tunnel was constructed in these kinds of compound strata geohazards such as sinkhole and large settlement are ready to happen this paper presents a field case of shield tunnelling which was conducted at the interface of mixed ground between completely weathered granite covered by residual sandy soil at humen guangdong china to prevent damage to existing buildings optimisation of tunnel construction parameters was adopted during construction lateral displacements of the subsoil around the tunnel and horizontal and vertical displacement hazards of seven buildings were monitored the monitoring results show that maximum settlements and lateral displacements of the buildings were 18 9 and 8 8 mm respectively which are all within the allowable value for buildings the construction parameters such as total thrust chamber container pressure grouting pressure and grouting volume are presented and inducing hazards limits to buildings are discussed the results show that the optimised tunnel construction parameters are sufficient in reducing the hazards of both existing buildings and surrounding soil during tunnel excavation

uniform sense normal simple shear of the continental lithosphere geophysical studies suggest that the thin crust characteristic of the basin and range province extends eastward beneath the west margin of the colorado plateau and rocky mountain regions in arizona and utah zones perhaps over 100 km wide may be defined bounded on the west by the east limit of upper crustal normal faults that account for more that 10 extension and on the east by the east limit of thinning beneath the colorado plateau a discrepancy exists within these zones between the negligible extension measurable in the upper crust and the substantial extension apparent from crustal thinning assuming the discrepant zone crust was as thick as or thicker than the colorado plateau rocky mountain crust prior to extensional tectonism if various theories appealing to crustal erosion are dismissed mass balance problems evident in the discrepant zones are most easily resolved by down to the east normal simple shear of the crust moving lower and middle crustal rocks that initially were within the zones up and to the west to where they now are locally exposed in the basin and range province west of the discrepant zones in both arizona and utah east directed extensional allochthons with large displacement are exposed these geophysical and geological observations complement one another if it is accepted that the entire crust in both arizona and utah failed during extension on gently east dipping east directed low angle normal faults and shear zones over a region several hundred kilometres wide large scale uniform sense normal simple shear of the crust suggests the entire lithosphere may do the same such a hypothesis predicts major lithospheric thinning without crustal thinning will occur in plateau areas in the direction of crustal shear in the case of the arizona utah and red sea extensional systems and possibly the death valley extensional terrain a broad topographic arch typically 1500 2000 m higher than the extended terrain is present suggesting lithospheric thinning in areas predicted by the hypothesis

characteristics of dewatering induced drawdown curve under blocking effect of retaining wall in aquifer summary for deep excavation pits that require the pumping of confined groundwater a combination of a retaining wall and dewatering with large diameter wells is usually adopted during excavation to improve safety since a retaining wall has a much lower hydraulic conductivity than the surrounding material in the aquifer blocking of seepage to prolong the seepage path of the groundwater outside of the pit is effective the retaining walls used during excavation dewatering cause hydraulic head drawdown inside the pit much faster than outside the pit thus difference in hydraulic head between inside and outside of the pit increases to investigate the mechanism of the blocking effect numerical simulation using the finite difference method fdm was conducted to analyze the effects of pumping in the pit the fdm results show that drawdown varies along the depth of the confined aquifer the influence factors of drawdown inside and outside the pit include insertion depth of retaining walls anisotropy of a confined aquifer and screen length of pumping wells in addition fdm results also show that the drawdown time curve can be divided into four stages in stage i drawdown inside the pit is very small and outside the pit it is almost zero in stage ii drawdown increases quickly with time in stage iii the drawdown curve is parallel to the cooper jacob curve on semi log axes and in stage iv the drawdown becomes constant these characteristics of the drawdown curve under the blocking effect of a retaining wall in an aquifer provide a way of estimating hydrogeological parameters according to pumping test results

polonaise 97 an international seismic experiment between precambrian and variscan europe in poland abstract the trans european suture zone tesz comprises a series of sutures that developed by palaeozoic amalgamation of the phanerozoic central europe onto the proterozoic baltica and east european plate during the formation of pangea within tesz the permian basin in poland forms the easternmost part of the permian central european basin which is bordered on the east by the east european craton eec and on the southwest by the bohemian massif the axis of the basin the mid polish trough parallels the edge of the eec the teisseyre tornquist zone ttz is a geological inversion zone in the polish trough a large seismic experiment the polonaise 97 project was conducted in poland during may of 1997 and targeted the deep structure of the tesz and the complex series of upper crustal features associated with it it included contributions from the geophysical communities in poland denmark the usa lithuania germany finland sweden and canada this large lithospheric seismic experiment deployed 613 instruments to record 64 shots along five profiles with a total length of about 2000 km moreover five multichannel seismic reflection stations 90 and 120 channels recorded all signals from shots two dimensional velocity models were derived by p wave tomographic inversion these models provide an initial interpretation of this massive data set and allow us to present a few significant seismic and tectonic observations one of the most important is a very distinct asymmetry between the maximum thickness of the sedimentary cover in the polish trough 16 20 km and the crustal root 50 km associated with tesz ttz

semi analytical solution to pumping test data with barrier wellbore storage and partial penetration effects abstract there exist some difficulties in determining aquifer parameters based on pumping test data within a partially penetrated retaining walls using traditional cooper jacob method many other site specific factors such as the effect of partially penetrating well and the large diameter of the wells cannot easily be accommodated in theoretical well formulae the semi log drawdown time curves affected by the effects of barrier wellbore storage and partial penetration well can be characterised by four distinct stages of drawdown i stage i drawdown is unaffected by the barrier ii stage ii drawdown is significantly influenced by the barrier iii stage iii the drawdown time curve runs parallel to that deduced from greenfield conditions and iv stage iv the drawdown becomes a constant value to handle the four distinct stages of drawdown a semi analytical method using the slope of the late time drawdown asymptote of stage iii for determining the transmissivity is proposed the horizontal intercept resulting from an extension of the late time drawdown asymptote from stage ii is used for determining the storage coefficient pumping test data from a case history are analysed using the proposed semi analytical method and the results obtained are compared with those deduced from the numerical simulation the comparison between the analytical results and those obtained from the numerical simulation appeared satisfactory

three dimensional seismic modelling of the crustal structure between east european craton and the carpathians in se poland based on celebration 2000 data summary in this paper we present results of 3 d first arrival tomography applied to data recorded in se poland during the celebration 2000 seismic experiment the target area covers ca 500 500 km 2 and represents a complex geological setting from old precambrian platform east european craton eec through the crustal blocks terranes that form the transeuropean suture zone tesz to the young alpine orogen the carpathians contrasting velocity distributions in various geological units makes the tomographic inversion challenging for this reason much attention was paid to the inversion methodology we tested multioffset and multiscale approaches by increasing the offset range in the multioffset inversion we have independently constrained different depth ranges of our model we have found that the multiscale method that is the gradual stepping from bigger to smaller model cells produced the preferred solution resolution of the resultant crustal model was determined by performing checkerboard and restoration resolution tests lateral resolution of the order of 25 km is inferred down to 10 km depth and 50 km down to 25 30 km depth we have also applied a quasi monte carlo analysis to determine the absolute errors of model parameters which to our knowledge is the first such attempt in case of a 3 d wide angle data set the mean uncertainties of our tomographic velocities are 0 1 km s 1 but some anomalies are recovered with

p and s wave velocity model of the southwestern margin of the precambrian east european craton polonaise 97 profile p3 the large scale seismic experiment polonaise 97 investigated the seismic structure of the crust and the uppermost mantle in the polish region of the trans european suture zone this paper covers the interpretation of seismic data along the 300 km long p3 profile which is located in the precambrian east european craton eec parallel to the teisseyre tornquist zone the recordings were of high quality with seismic energy detectable out to 300 km ovsets the crustal model developed by two dimensional raytracing forward modelling and waveform analysis is characterized by a subhorizontal uniform structure although the boundaries of several large basement features are crossed the crystalline crust consists of three parts the upper middle and lower crust with p wave velocities of 6 1 6 4 km s 6 55 6 7 km s and 7 05 7 15 km s respectively the p m p wave can usually be correlated at distances beginning at about 100 km but it has variable reflection character moho depth increases from 38 km at the nw end of the profile to 44 km at the se end the p n velocity of 8 05 8 1 km s is less than that previously found in neighbouring areas of the eec the v p v s ratio was determined separately for the upper middle and lower crust to be 1 67 and 1 77 respectively following the p n wave another phase with an apparent velocity of about 8 3 km si s interpreted as a weak reflection from a low contrast discontinuity in the uppermost mantle 1999 elsevier science b v all rights reserved

investigation of field installation effects of horizontal twin jet grouting in shanghai soft soil deposits this paper presents a case study of an investigation into the responses of the surrounding ground to the horizontal twin jet grouting method htjgm in soft soil deposits of shanghai during the fi

seismic and geological structure of the crust in the transition from baltica to palaeozoic europe in se poland celebration 2000 experiment profile cel02 abstract the celebration 2000 together with the earlier polonaise 97 deep seismic sounding experiments was aimed at the recognition of crustal structure in the border zone between the precambrian east european craton baltica and palaeozoic europe the cel02 profile of the celebration family is a 400 km long sw ne transect running in poland from the upper silesia block usb across the malopolska block mb and the trans european suture zone tesz to the east european craton eec the structure along cel02 was interpreted using both 2d tomography and forward ray tracing techniques as well as 2d gravity modelling the crustal thickness along cel02 varies from 32 35 km in the usb to 45 47 km beneath the tesz and the eec the usb is a clearly distinctive crustal block with the characteristic high velocity lower crust 7 1 7 2 km s interpreted as a fragment of gondwana the krakow lubliniec fault is a terrane boundary produced by soft docking of the usb with the mb the malopolska crust fundamentally differs from the usb and has a strong connection with baltica it is a transitional 150 to 200 km wide unit composed of the extended baltican lower crust and the overlying low velocity 5 15 5 9 km s neoproterozoic metasediments in the up to 18 km thick upper crust the ysogory unit has its crustal structure identical with that of malopolska thus it is connected with baltica and cannot be interpreted as a gondwana derived terrane higher velocity and density bodies found below the mazovia lublin graben at a depth of 12 km and at the base of the lower crust might be a result of mantle derived mafic intrusions accompanying the extension of baltica by the preliminary 2d gravity modelling we have reconfirmed the need for considering the increased tesz mantle density in comparison to the eec and usb mantle

2 d seismic tomographic and ray tracing modelling of the crustal structure across the sudetes mountains basing on sudetes 2003 experiment data the seismic data obtained during sudetes 2003 experiment are analysed and detailed crustal structure for profiles s02 s03 and s06 is presented using three different 2 d techniques 1 smooth tomography of refracted waves travel times 2 ray tracing of reflected and refracted waves and 3 joint velocity and depth of reflector tomographic inversion in spite of different interpretation techniques used the models of the crustal structure show common characteristic features the low velocity vp 4 km s sedimentary layer was documented in the northeastern part of the study area the topmost basement has in general a velocity of 5 8 6 0 km s and velocities at ca 20 km depth are 6 15 6 25 km s the strong reflecting boundaries were found at 20 23 and 25 28 km depth with a velocity contrast about 0 4 km s and the highest velocities in the lowermost crust are 6 8 7 2 km s in general the crust of the bohemian massif is slightly thicker 33 35 km than in the northern part of the area velocities beneath moho are relatively low of 7 95 km s on the basis of well recorded reflected waves mantle reflectors were discovered in the depth interval ca 40 70 km apart of new results for the geology and tectonics of the area some conclusion could be made about different techniques used in the 2 d case the clasical ray tracing method with using all correlated phases gives the most adequate model of the structure because of full manual control of the model creation the smooth first arrival travel times tomography although very fast is not satisfactory enough to describe the complex structure so the best candidate in 3 d case seems to be travel time tomography for both refracted and reflected waves in multi layers models

crustal structure of the trans european suture zone region along polonaise 97 seismic profile p4 1 the large scale polonaise 97 seismic experiment investigated the velocity structure of the crust and upper mantle in the trans european suture zone tesz region between the precambrian east european craton eec and paleozoic platform that comprises terranes added during the caledonian and variscan orogenies 530 370 and 370 225 ma respectively this experiment included 64 shots recorded by 613 seismic stations during two deployments very good quality data were recorded along five profiles and the longest and most important one p4 is the focus of this paper clear first arrivals and later phases of waves reflected refracted in the crust and moho were interpreted using two dimensional 2 d tomographic inversion and ray tracing techniques the crustal thickness along the profile varies from 30 35 km in the paleozoic platform area to 40 km below and due northeast of the tesz to 43 km in the polish part of the eec and to 50 km in lithuania the paleozoic platform and eec are divided by the polish basin so the upper crustal structure varies considerably in the area of the polish basin the p wave velocity is very low vp 6 1 km s down to depths of 15 20 km indicating that a very thick sedimentary sequence is present we suggest two possible tectonic interpretations of the velocity models 1 baltica indented avalonia obducting its upper crust and underthrusting its lower crust in a tectonic flake structure and 2 a rifted margin of baltica underlies the polish basin this model is similar to other interpretations of seismic profiles recorded in the baltic sea the second model implies that the paleozoic platform solely consists of avalonian lithosphere and the eec of baltica lithosphere it offers a simple explanation of the difference in crustal thickness of the two platforms it also implies that the caledonian and variscan orogenies in this area were relatively soft collisions that left this continental margin largely intact

deep structure of the earth s crust in the contact zone of the palaeozoic and precambrian platforms in poland tornquist teisseyre zone abstract one of the major tectonic problems in europe concerns the southwest margin of the east european platform in the region of the so called polish danish trough in general this margin is assumed to be the tornquist teisseyre t t line running approximately from northwest to southeast in this part of europe determination of deep crustal structure of the contact zone between the precambrian platform and the palaeozoic platform was the main aim of the deep seismic sounding dss programme in poland in 1965 1982 deep seismic soundings of the earth s crust have been made in the t t line zone along nine profiles with a total length of about 2600 km the results of deep seismic soundings have shown that the crust in the marginal zone of the east european platform has highly anomalous properties the width of this zone ranges from 50 km in northwest poland to about 90 km in southeast poland the crustal thickness of the palaeozoic platform in poland is 30 35 km and of the precambrian platform 42 47 km while in the t t tectonic zone it varies from 50 to 55 km above the moho boundary in the t t zone at a depth of 40 45 km there is a seismic discontinuity with p wave velocities of 7 5 7 7 km s boundary velocities mean velocities and stratification of the earth s crust vary distinctly along the t t zone there are also observed high gravimetric and magnetic anomalies in the t t zone the t t tectonic zone determined in this manner is a deep tectonic trough with rift properties the deep fractures delineating the t t tectonic zone are of fundamental importance for the localization of the plate edge of the precambrian platform of eastern europe in the light of dss results the northeastern margin of the t t tectonic zone is a former plate boundary of the east european platform