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Showing papers on "Lateral earth pressure published in 2004"


Journal ArticleDOI
TL;DR: In this article, the authors explored the magnitude and distribution of dynamic earth pressures on several types of flexible retaining systems: L-shaped reinforced-concrete walls, piled walls with horizontal or with strongly inclined anchors, and reinforced-soil walls.

100 citations


Journal ArticleDOI
TL;DR: In this paper, a procedure for assessing the required long-term strength of the reinforcement while considering its limited length is introduced. But, often there are constraints on such space; e.g., bedrock formation located at a small distance behind the facing.

60 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of pore pressure response around a pile on p-y behavior, defined as the relation between subgrade reaction and relative displacement between soil and pile, is examined based on large shaking table tests conducted on pile-structure systems constructed in liquefiable soil deposits.

55 citations


Journal ArticleDOI
TL;DR: In this paper, a large-scale laminar box with 4 m in length, 2 m in width and 2m in height was used to investigate the behavior of a soil-pile-superstructure system in liquefiable ground.

51 citations


Journal ArticleDOI
TL;DR: In this article, the bearing capacity of unsaturated expansive soil is derived by considering the effect of the expansive lateral pressure in Terzaghi's bearing capacity formula, which is related to the drying and wetting environment.
Abstract: It is difficult to determine the bearing capacity of a foundation in unsaturated expansive soil, although this is most important. The bearing capacity of unsaturated expansive soil is related to the drying and wetting environment. Swelling pressure occurs when the soil volume change is constrained as an expansive soil is inundated. The expansive lateral pressure, induced by the swelling pressure is similar to the passive earth pressure. By considering the effect of the expansive lateral pressure in Terzaghi's bearing capacity formula, the bearing capacity of unsaturated expansive soil is derived. Because it is very difficult to measure suction in situ, the bearing capacity is expressed using the expansive lateral pressure offers a feasible approach to calculate the bearing capacity of a foundation in unsaturated expansive soil, when suction is not measured. Plate load tests to measure the bearing capacity in situ were performed for the foundation in natural soil and saturated soil immersed by water. The verification of the bearing capacity formulae presented in this paper is conducted by comparing the predicted results with the results of the plate load tests on unsaturated expansive soils in Handan and Bingxia, China.

40 citations


Journal ArticleDOI
TL;DR: In this paper, the failure mechanism and ground movement behavior around tunnels embedded in sandy soil below the water table were investigated in a series of model tunnel tests in a centrifuge and the magnitudes and extents of the surface settlement troughs for the cases of various ground loss for tunnels buried at various depths were provided.
Abstract: Tunneling may cause ground movements and damage to adjacent buildings and overlying facilities. In this study, the failure mechanism and ground movement behavior around tunnels embedded in sandy soil below the water table were investigated in a series of model tunnel tests in a centrifuge. The magnitudes and extents of the surface settlement troughs for the cases of various ground loss for tunnels buried at various depths are provided. A new failure mechanism is proposed and validated by comparison with the test results. The proposed mechanism enables accurate prediction of two of the key quantities in the design of linings for tunnels embedded in sandy soils, namely the minimum supporting pressure needed to retain tunnel stability and the vertical soil pressure acting on the tunnel crown.

40 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated the influence of tunnel excavation on surface settlement and earth pressure surrounding a tunnel, both the model tests and numerical simulations were conducted considering the ground as green field.

38 citations


T Hashimoto, J Brinkman, T Konda, Y Kano, A Feddema 
01 Jul 2004
TL;DR: In this article, a back analysis was performed based on the conventional Japanese design method, and the conclusion was that the tunnel seems to be over designed using the traditional Japanese design methods, and it is necessary to improve and develop a more rational design method for the future.
Abstract: Over the years it has become clear that simultaneous backfill grouting is of major importance to the design of the tunnel lining and TBM process control. Considerable research has been conducted in the last 20 years to get a grip on these two aspects. Good grouting is the key to successful settlement control, reducing the differential displacement between segments and rings, the moments in the lining (in both ring- and longitudinal direction), and for optimization of the tunnel boring process. Simultaneous backfill grouting was carried out in shield tunnelling for the first time in 1982, in the construction of No. 4 line of the Osaka Subway in Japan. The conventional method using mortar grouting had been expected to cause a ground settlement of 50-100 mm when tunnelling through very sensitive soft clay. The use of simultaneous backfill grouting kept the settlement in a 10-30 mm range (Hirata, 1989). Since then, this method has been introduced in many regions of the world, such as Asia, Europe and America, reducing the settlement associated with shield tunnelling. The next step was the optimization of the material properties of the grout. Extensive research resulted in the two-component grout TAC (in Europe: ETAC) which gave: (1) A more efficient tunnel boring process because there is no clogging of the grout in the injection system. (2) Faster and uniform support of the tunnel lining. (3) Settlements in the range of 0-15 mm, through the better control of the grout injection. In the paper the two-component injection system is explained and a typical example for the composition and the behaviour of the grout is given. A figure with the conceptual grout pressure change versus time is presented for different soil types and different grouting pressures. Grouting pressure due to simultaneous backfill grouting starts acting on the circumference of the lining immediately after the passage of the shield tail. The grouting pressure distribution becomes uniform shortly after the grouting because the grout is in a plastic state. With hardening, the grout holds the earth pressure and the water pressure in the ground and conveys them to the tunnel lining. After hardening of the grout, the lining pressure changes depending on the compression of the grout, the deformation of the lining, stress relaxation, and so on, and then reaches a steady value. The magnitude of the pressure change is depends on the ground conditions, e.g. hard or soft soil, and also on the magnitude of injection pressure. In the case of soft soil, the lining pressure approaches the initial stress with time, regardless of the injection pressure. In the case of hard soil, the lining pressure approaches the active earth pressure. A case history, with the development of the grouting pressure from the construction phase until 6 months later is presented and discussed. An overview is given, with field measurements, of about 35 cases with grout pressures at two days after tail passage. These cases have been grouped as: soft clay soil, stiff clay soil and sand/sandy gravel. Finally, from measured grout pressure distributions for three cases the resulting bending moments in the lining have been calculated. A back analysis was performed based on the conventional Japanese design method. The conclusion of this back analysis was that the lining seems to be over designed using the conventional Japanese design method. It was concluded that, it is necessary to improve and develop a more rational design method for the future. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.

36 citations


Journal ArticleDOI
TL;DR: In this article, a new pseudo-static method was developed to evaluate the seismic stability of retaining walls situated on slope, and the results showed that the stability of the wall against bearing capacity failure may be greatly overestimated when the inertia of soil mass is not taken into account.
Abstract: Many soil retaining walls, which were used to stabilize highway embankments constructed on hillside, were severely damaged during the major earthquake (Chi-Chi earthquake, M\dL = 7.3) on September 21, 1999 in Taiwan. We investigated two typical cases of soil retaining wall damage using survey, soil borings and soil tests. To this end we developed a new pseudo-static method to evaluate the seismic stability of retaining walls situated on slope. Sliding failure along the wall base and bearing capacity failure in the foundation slope were considered in the new pseudo-static method. Results of the analysis showed that seismic stability of the wall against bearing capacity failure may be greatly overestimated when the inertia of soil mass is not taken into account. The analytical results also showed that sliding failure along the wall base occurs prior to the bearing capacity failure of the wall situated on a gentle slope at Site 1. The opposite is true for the wall situated on a steep slope at Site 2. For soil retaining walls constructed on slope, sliding failure of the wall may occur under small input horizontal ground acceleration when the passive resistance in front of the wall is not effectively mobilized. This highlights the importance of improving the strength of backfilled soils in the passive zone when constructing soil retaining walls on slope. The results obtained in the present study also suggest a modification of the current design considerations for soil retaining walls situated on slope.

34 citations


01 Jan 2004
TL;DR: In this paper, a thorough state-of-the-art on the soil-structure-interaction issues of integral bridges and culverts is provided, focusing on the earth pressure behind integral-bridge abutments.
Abstract: A thorough state of the art on the soil-structure-interaction issues of integral bridges and culverts is provided, focusing on the earth pressure behind integral-bridge abutments. The procedure of the Swedish design code for estimating the earth pressure response to integral bridge abutment movement is found to be conservative compared to the one of the British code and to some recent experimental studies. The influence of soil stiffness and different ways of acquiring this parameter are discussed. Upon comparison of several methods for the determination of the elasticity modulus of soil, it can be concluded that the E s values of Duncan et al.'s SCI method are much more conservative than the E t values by Duncan et al.'s hyperbolic equation and Pettersson et al.'s Method 2. Also, there are significant differences between that Method 2 and Lehane et al.'s and Lade et al.'s methods. The results of the bending moment calculations done on three culverts with different height-to-span ratios suggest that live-load moments are very sensitive to the stiffness of the backfill soil. The bending moments due to live loads are also sensitive to cover depths. For low covers, the moments are much more sensitive to changes in cover depth. This demonstrates how and when arching effects actually take place. The moment calculations for a typical slab-frame bridge reveal that the moments at the abutment front are reduced significantly as the soil stiffness changes from very low to high. The effect of change of the parameter in the passive soil-response formula of the Swedish bridge design code on moments is also significant.

32 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of diaphragm wall construction on the stress field in a soft clayey soil is investigated by the use of a three-dimensional FE-model of seven adjacent wall panels.
Abstract: The influence of a diaphragm wall construction on the stress field in a soft clayey soil is investigated by the use of a three-dimensional FE-model of seven adjacent wall panels. The installation procedure comprises the excavation and the subsequent pouring of each panel taking into account the increasing stiffness of the placed fresh concrete. The soft clay deposit is described by a visco-hypoplastic constitutive model considering the rheological properties and the small-strain stiffness of the soil. The construction process considerably affects the effective earth and pore water pressures adjacent to the wall. Due to concreting, a high excess pore water pressure arises, which dissipates during the following construction steps. The earth pressure finally shows an oscillating, distinct three-dimensional distribution along the retaining wall which depends on the installation sequence of the panels and the difference between the fresh concrete pressure and the total horizontal earth pressure at rest. In comparison to FE-calculations adopting the earth pressure at rest as initial condition, greater wall deflections and surface ground settlements during the subsequent pit excavation can be expected, as the average stress level especially in the upper half of the wall is increased by the construction procedure of the retaining structure. Copyright © 2004 John Wiley & Sons, Ltd.

Journal Article
Gao Xi-feng1
TL;DR: In this article, a new plane finite element model considering double row pile soil interaction was presented, where soil between double row piles was regarded as a thin compressible layer and was simulated by a series of horizontal rings connecting the double rows.
Abstract: Based on the current model of calculating double row piles, the new plane finite element model considering the pile soil interaction was presented in this paper. Soil between double row piles was regarded as a thin compressible layer and was simulated by a series of horizontal rings connecting the double row piles,so that the effects of the change of soil profile, compressibility and the treatment of soil between double row piles on the interaction between the double row piles could be considered in the analysis with no supposition of the sharing of total soil pressure between double row piles needed. The calculated results of the interaction of double row piles of an actual engineering project by the presented model showed that satisfactory result can be obtained with reasonable parameters applied in the model.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the influence of tunnel excavation on surface settlement and earth pressure surrounding a tunnel in a finite element model using elastoplastic subloading tij model.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the load transfer behavior along bored piles in Singapore and the impact of pile construction on the soil modulus by using a hyperbolic function and a modulus reduction factor, based on triaxial compression and pressure meter tests on the residual soil.
Abstract: The load transfer behavior along bored piles is affected by details of pile construction particularly those imposing stress and moisture changes to the surrounding soils. An investigation involving moisture migration tests, in situ horizontal stress measurements, and borehole shear and pressuremeter tests shows clear effects of construction that lead to subsequent changes in soil properties. The construction of bored piles in Singapore and the region often involves casting of concrete either in unsupported dry boreholes or in wet boreholes filled with water. It is necessary to differentiate these two extreme construction conditions in bored pile design. Based on triaxial compression and pressuremeter tests on the residual soil of the Jurong Formation in Singapore, the variation of soil modulus with shear strain can be described by a hyperbolic function. A procedure is recommended for assessing the combined effect of stress relief and soaking on soil modulus by introducing a modulus reduction factor. Modulus degradation curves from pressuremeter tests with the borehole conditions properly simulated are found capable of producing load transfer curves that are comparable to those deduced in the field.

Journal ArticleDOI
TL;DR: In this paper, a methodology to identify the collapse potential of unsaturated soils is proposed on the basis of pressuremeter test results associated with independent measurements of the in situ matric suction.
Abstract: A methodology to identify the collapse potential of unsaturated soils is proposed in this paper on the basis of pressuremeter test results associated with independent measurements of the in situ matric suction. A solution combining the expansion of a cylindrical cavity to a modified Cam clay critical state model has been introduced and accommodated to the framework of unsaturated soil behavior. This accounts for changes in soil properties induced by suction changes. Interpretation of pressuremeter tests performed under unsaturated and soaked conditions links the amount of collapse to strength and stiffness changes and provides assessment to the constitutive soil parameters that are necessary to define the yield envelopes of the soil. A comprehensive site investigation program comprising field and laboratory tests carried out in two residual soil sites is discussed in order to validate the proposed methodology. Values of shear strength, in situ stress, and yield pressure derived from both field and laboratory data are used as input parameters of a constitutive model adopted for describing the yield envelopes of these unsaturated residual soil sites.

Journal ArticleDOI
TL;DR: In this paper, the authors examined the usefulness of the soil stiffness gauge in thermoplastic pipe installation work and discussed the ability of this tool to realistically measure the stiffness of the backfill soil placed around the thermoprocessor.
Abstract: The soil stiffness gauge is a new tool for measuring the stiffness of a soil layer quickly in the field. It is anticipated that this type of portable device will be utilized in a variety of geotechnical projects in the future, since stiffness is a better indicator of the quality of soil fill than dry density. This paper examines the usefulness of the soil stiffness gauge in thermoplastic pipe installation work. Comprehensive data obtained during the initial stage of the thermoplastic pipe deep burial project in Ohio are reviewed to discuss the ability of the soil stiffness gauge to realistically measure the stiffness of the backfill soil placed around thermoplastic pipe and the ability of the soil modulus derived from the soil stiffness gauge readings to predict the horizontal deflections of the thermoplastic pipe under moderate to deep soil cover.

Journal ArticleDOI
TL;DR: Vibrating-wire earth pressure cells are often used to measure soil pressure in fills and embankments or contact pressure between soil and buried structures as discussed by the authors, but they are not suitable for outdoor applications.
Abstract: Vibrating-wire earth pressure cells are often used to measure soil pressure in fills and embankments or contact pressure between soil and buried structures. Instrumentation companies provide each c...

Proceedings ArticleDOI
TL;DR: In this article, the authors describe a number of experiences obtained from two projects, including large scale ground improvements by cement-mixing in place and construction of large offshore embankments using cement-mixed sand.
Abstract: This report describes a number of experiences obtained from two projects. Firstly, among a number of significant geotechnical design and construction issues of the Trans-Tokyo Bay Highway project, large scale ground improvements by cement-mixing in place and construction of large offshore embankments using cement-mixed sand are described. The related strength and deformation characteristics of cement-mixed soil are summarized and compared with those of natural sedimentary soft rocks. A new method to determine the design strength of cement-mixed soil, adopted in this project, is described. Secondly, recent construction of a bridge abutment consisting of the backfill of geogrid-reinforced cement-mixed gravel and a thin RC facing structure supporting a bridge girder for a new bullet train is described. This structure is unique in that the backfill supports laterally the RC facing, rather than exerting static and dynamic earth pressure on the facing. Results from triaxial compression tests on cement-mixed gravel and dynamic loading model tests as well as field full-scale loading tests are reported.

Patent
14 Jul 2004
TL;DR: In this article, the utility model relates to a novel tester in a pilesoil function chamber to test mutual function of pile-soil in different working condition in the chamber by the mode of sleeve line balanced afterburning.
Abstract: The utility model relates to a novel tester in a pile-soil function chamber to test mutual function of pile-soil in different working condition in the chamber by the mode of sleeve line balanced afterburning. The tester contains a cladding earth pressure loading device, a barrel body, a balanced loading system etc. A plurality of sleeve lines go through the side wall of the barrel body, the barrel bottom and the loading cover to form paired afterburning on pre-buried models; mutual function of pile-soil while suffering from vertical force and lateral force or the bending moment respectively or simultaneously under the cladding earth pressure can be tested in the chamber and pile-soil function under alternating loads can be also tested. The utility model is applicable to researching foundation bearing mechanism and testing various foundation bearing abilities.

Journal ArticleDOI
TL;DR: In this paper, the application of kinematically admissible mechanisms for the description of typical passive pressure soil mechanics boundary value problems has been presented and a numerical example based on the method is presented for the multiple failure switches resulting from an advanced earth moving tool displacement.
Abstract: The application of kinematically admissible mechanisms for the description of typical passive pressure soil mechanics boundary value problems has been presented. First, basic relations concerning material behavior along velocity discontinuity lines are discussed. Then the block equilibrium method is presented and two material models are considered. The originally presented solution for a linear Mohr–Coulomb material is compared with the solution obtained for a nonlinear material. The sensitivity of the soil failure mechanisms to material parameters is discussed. In fact, different kinematic mechanisms of soil deformation occurred for the same test conditions. Finally, a numerical example based on the method is presented for the multiple failure switches resulting from an advanced earth moving tool displacement.

Journal Article
TL;DR: In this paper, the evolution of shear zones in granular bodies for earth pressure problems of a retaining wall in conditions of plane strain was analyzed and the passive and active failure of the retaining wall was discussed.
Abstract: The evolution of shear zones in granular bodies for earth pressure problems of a retaining wall in conditions of plane strain was analyzed. The passive and active failure of a retaining wall was discussed. The calculations were carried out with a rigid and very rough retaining wall undergoing horizontal translation, rotation around the top and rotation around the bottom. The behaviour of dry sand was numerically modelled with a finite element method using a hypoplastic constitutive relation with polar extensions. Attention was paid to the influence of different wall movements on shear localization. The initial void ratio was assumed to be non-uniformly distributed. The geometry of calculated shear zones was compared with corresponding experimental results of laboratory model tests.

Proceedings ArticleDOI
TL;DR: In this paper, a mechanically stabilized earth wall reinforced with geotextiles and geogrids and backfilled with a sand-tire shred mixture (25% tire shreds by volume) was designed and constructed using conventional geotechnical methods.
Abstract: In this study, soil-tire shreds were used as a backfill material behind a fully instrumented modular wall. A mechanically stabilized earth wall reinforced with geotextiles and geogrids and backfilled with a sand-tire shred mixture (25% tire shreds by volume) was designed and constructed using conventional geotechnical methods. After construction, the wall was loaded with a surcharge and monitored to assess the mass behavior of soil-tire shred backfills. Successive surcharges were placed corresponding to 42, 95, 148 and 200 kPa. The wall was instrumented with earth pressure cells, position transducers to measure displacement of the wall face, and strain gages to monitor strains in the geosynthetic reinforcement. Horizontal and vertical pressures behind the wall increased as the surcharge was placed, but at different rates depending on depth. Stain in the geotextile and geogrid layers also increased as the surcharge increased, with larger strains occurring near the face of the wall. Displacements o the face of the wall were largest near the top, and increased as the surcharge was placed. However, the displacements generally were small, even under the heavy surcharge. A favorable comparison was also obtained between deformations predicted using finite element model and those measured in the field. The small displacements that were observed demonstrated that earth structures using soil-tire shreds backfills can be reliably designed and constructed with conventional geotechnical methods.

Journal ArticleDOI
TL;DR: In this paper, a method for predicting stresses in pavements under vehicular loadings is proposed, which characterizes each pavement layer by a coefficient of lateral stress, which is similar to the commonly used coefficients of lateral earth pressure (K).
Abstract: The present study proposes a method for predicting stresses in pavements under vehicular loadings. The proposed method characterizes each pavement layer by a coefficient of lateral stress, which is similar to the commonly used coefficient of lateral earth pressure (K). Stress predictions found by the proposed method are compared with stress predictions calculated by conventional linear elastic techniques. Each conventional solution is shown to represent a special case of the more global proposed solution. Several instrumented test sections are explored to determine coefficients of lateral stress for common paving materials.

Journal ArticleDOI
TL;DR: In this article, an analytical method for a geosynthetic-reinforced granular fill-soft soil system subjected to a load, moving at constant velocity, over an infinitely long beam is presented.
Abstract: This paper presents an analytical method for a geosynthetic-reinforced granular fill–soft soil system subjected to a load, moving at constant velocity, over an infinitely long beam. The upper reinforced granular bed is modelled by a rough membrane embedded in a Pasternak shear layer overlying a series of compressible Winkler springs representing the underlying soft soil. Parametric studies reveal that velocity, load intensity and compressibility of granular fill have significant effects on both the flexural response of the infinite beam and the reinforcement. In contrast, interfacial frictional coefficients, shear modulus of granular layers and coefficient of lateral earth pressure do not affect the response of the beam.

Journal ArticleDOI
Sami Arsoy1
TL;DR: In this article, the authors proposed a method to estimate the magnitude of the resultant force and the point of application of the resulting force as a function of the wall displacement in a bridge without expansion joints.
Abstract: Bridges without expansion joints are referred to as integral bridges. The abutment and the superstructure of integral bridges act as a single structural unit. As the temperature of an integral bridge changes, the length of the bridge increases and decreases. The changes push the abutment against the approach fill and pull it away and thus cause lateral deflections. The movement of the abutment into the approach fill develops passive earth pressure that is displacement dependent. Although earth pressures are detrimental for the substructure of a bridge, they are beneficial for the superstructure because they reduce the bending moments caused by the dead loads and the live loads in the bridge girders. Therefore, relying on the beneficial effects of the full passive earth pressures, regardless of the displacement, is not conservative. Charts are proposed to estimate the magnitude of the resultant force and the point of application of the resultant force as a function of the wall displacement. Medium-dense an...

Journal ArticleDOI
TL;DR: In this article, the Coulomb's theory was used to obtain the theoretical answers to the unit earth pressure, the resultant earth pressure and the point of application for the wall movement mode of rotation about top.
Abstract: Based on the Coulomb's theory that the earth pressure against the back of a retaining wall is due to the thrust exerted by the sliding wedge of soil from the back of the wall to a plane which passes through the bottom edge of the wall and has an inclination equal to the angle of τ, the theoretical answers to the unit earth pressure, the resultant earth pressure and the point of application of the resultant earth pressure on a retaining wall were obtained for the wall movement mode of rotation about top. The comparisons were made among the formula presented here, the formula for the wall movement mode of translation, the Coulomb's formula and some experimental observations. It is demonstrated that the magnitudes of the resultant earth pressures for the wall movement mode of rotation about top is equal to that determined by the formula for the wall movement mode of translation and the Coulomb's theory. But the distribution of the earth pressure and the points of application of the resultant earth pressures have significant difference.

01 Jul 2004
TL;DR: In this paper, a 3D coupled pore water flow/stress-strain finite element model of the TNEC-excavation pit in Taipei has been generated to evaluate the influence of the diaphragm wall construction on wall movements and settlements due to the pit excavation.
Abstract: Deep excavations in soft soil deposits frequently cause large wall deflections and surface ground settlements, which possibly compromise the serviceability of neighbouring structures. Therefore, ground movements have to be estimated by the use of numerical methods already at the design stage of the retaining structure. Conventional finite element models choose the earth pressure at rest as initial conditions at the beginning of the excavation process. However, in the case of a diaphragm wall, the installation of the wall panels incorporating the trench excavation under slurry support and the subsequent pouring of the panels precedes the pit excavation. In order to evaluate the influence of the diaphragm wall construction on wall movements and settlements due to the pit excavation, a three-dimensional coupled pore water flow/stress-strain finite element model of the TNEC-excavation pit in Taipei has been generated. The model comprises the stepwise construction of five adjacent 5 m long wall panels as well as the simulation of the subsequent excavation of the pit. For each panel, the trench excavation is modeled by removing the respective elements inside and placing distributed loads, which represent the hydrostatic slurry pressure. Afterwards, the loads are increased to the adopted bi-linear fresh concrete pressure and are finally replaced by additional finite elements simulating the concrete. The increasing stiffness of the fresh concrete due to aging is considered by a suitable evolution of the Young's modulus and the Poisson ratio. A visco-hypoplastic constitutive model is used to describe the clayey soil deposits taking into account the viscous behavior of the ground. After the completion of all the panels, the effective lateral stress adjacent to the diaphragm wall shows an oscillating distribution and strongly differs from the initial earth pressure at rest. This development is mainly affected by the distribution of fresh concrete pressure. At lower depth, the concrete pressure exceeds the total earth pressure at rest in normally- to slightly over-consolidated soil deposits, which results in a stress concentration in the middle in conjunction with an unloading besides the panel during the pouring process. At greater depth however, the concrete pressure is lower than the initial total earth pressure. Therefore, a stress increase in the middle of the panel takes place and a horizontal arching mechanism causes a stress increase besides the trench. Taking this different pressure condition during the subsequent pit excavation into account, the calculated wall deflections and the surface ground settlements differ from those of a conventional finite element model neglecting the installation process of the wall. However, the difference of wall movements is less than 5%, so the influence of the panel construction is of minor interest for the considered TNEC-pit. One reason might be the numerous strutting levels of the top-down construction, which generally limit the deflections. On the contrary, the settlements increase up to 20% and fit the measurements obviously better than those ones calculated by a conventional FE-model. Especially in the case of an adjacent structure in urban areas, it can be expected that the impact of the panel installation process will even increase the settlements and that a neglect of this effect will lead to a loss of accuracy of the predicted ground movements. (A). "Reprinted with permission from Elsevier". For the covering abstract see ITRD E124500.

Journal Article
TL;DR: In this article, the dynamic interaction between structures and layered soils during earthquakes was studied analytically, where the total earth pressure against the sidewalls of the structure was simplified to be proportional to the corresponding lateral soil-wall displacement during an earthquake.
Abstract: The dynamic interaction between structures and layered soils during earthquakes was studied analytically The total earth pressure against the sidewalls of the structure was simplified to be proportional to the corresponding lateral soil-wall displacement during an earthquake The structure and its surrounding soil layers were assumed to act as a group of visco-elastic beams which displace only in the horizontal direction As a result, the analytical solution describes the dynamic soil-structure response for the simpler condition where a structure is partially buried in layered soils The solution accurately describes the dynamic response at any spot in the soil and structure during an earthquake The solution was employed to calculate the dynamic acceleration and displacement response of a partially buried structure in layered soils with different shear moduli distributions The results show that the mechanical characteristics of the layered soils significantly affect the dynamic structure response and the earth pressures acting on the structure

01 Jan 2004
TL;DR: In this article, the authors investigated the unloading modulus of soft clays in an excavation for the Gotaleden tunnel in Gothenburg, Sweden and found that the initial stiffness was three times greater than that observed in the Bender element tests, which is likely to be an effect of creep or stress path rotation.
Abstract: Improved infrastructure in urban areas often necessitates underground construction, where the unloading behaviour of the soil is of importance for predicting the amount of heave and how long it will take for the soil to swell. It is of particular interest to study the need for the installation of tension piles, as well as whether the tunnel will be subjected to settlement or heave in the long term. The objective of this study was to investigate the unloading behaviour of soft clay, and thereby reducing the uncertainties associated with this type of construction in future projects. This paper focuses on the unloading modulus of soft clay and includes results from a field and laboratory study. Previous studies on the unloading of clay have mainly employed laboratory methods to determine the unloading modulus, and these results are compared with the results of this project. The field study was conducted at an excavation for the Gotaleden tunnel in Gothenburg. Extensive measurements of heave and pore pressures were performed at the construction site during a period of over one year. Several piezometers, earth pressure cells measuring total pressure and pore pressure, heave gauges and extensometers were installed at the centre of the excavation. The results were analysed and the unloading modulus was estimated from the measurements. The laboratory tests mainly consisted of incrementally loaded oedometer tests and drained triaxial extension tests. Bender elements were used in the triaxial apparatus to measure the initial soil stiffness. The results show a very high initial stiffness, which corresponds well with field measurements (Andreasson, 1979). The laboratory test results reveal that it is possible to capture the small strain behaviour in the clay, using advanced triaxial test equipment and measurement techniques. However, results from the field study indicate a noticeably stiffer behaviour, than ordinary laboratory tests. Differences in the results were expected due to the difficulty of recreating the in-situ characteristics of the clay specimen in the laboratory. Proposed curves for the variation of the unloading modulus with stress level are presented for normally to slightly overconsolidated clays. The study shows that the unloading modulus has a large initial value, which drops considerably with the decrease in stress. The creep in the clay prior to unloading is a factor that has a major influence on the initial stiffness. The field results indicate an initial stiffness three times greater than that observed in the Bender element tests, which is likely to be an effect of creep or stress path rotation. In the excavation at hand, the heave process seems to have terminated within three months of completion of the excavation, coinciding with the time at which steady state pore pressures were reached, which was considerably faster than originally expected.

Journal Article
TL;DR: According to Rankine theory of earth pressure, and analysis of relationship between active and passive and static earth pressure and displacement of retaining wall, an approximate calculation method for earth pressure considering displacement is presented in this article.
Abstract: According to Rankine抯 theory of earth pressure, and analysis of relationship between active and passive and static earth pressure and displacement of retaining wall, an approximate calculation method of earth pressure considering displacement is presented. The rule of earth pressure varying with displacement presented in this paper is well comparable with the results of the finite element analysis.