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To comprehensively consider the influence of boundary conditions, non‐Darcy flow, load forms, and soil stratification on soil consolidation, a one‐dimensional soil consolidation equation is established. By subdividing the soil layer and employing time discretization, the nonlinear consolidation equation is linearized, resulting in an analytical solution for layered soil foundation at any given time. Subsequently, an iterative approach for time solution is employed to obtain a semi‐analytical solution. The correctness of the solution is verified by comparison with solutions based on Darcy's flow and the semi‐analytical method under traditional drainage boundary conditions. Subsequently, the influence of interface parameters, loading conditions, flow index, and other factors on consolidation characteristics is analyzed. The results indicate that higher interface parameter values for continuous drainage boundaries correspond to faster average consolidation rates for stratified soil foundations, while these parameters have little effect on the time required for complete consolidation of the soil layers. Improved boundary drainage performance amplifies the influence of exponential flow on pore water pressure and average consolidation degree. Conversely, poor boundary drainage performance diminishes the impact of exponential flow on soil consolidation, rendering it negligible. Moreover, faster loading rates accentuate the influence of the flow index on the average consolidation degree defined by pore pressure. [ABSTRACT FROM AUTHOR]

ABSTRACT Energy piles are commonly deployed in vertically layered geological conditions due to the geological structure and pile foundation backfill. The imperfect contact between adjacent soil layers results in resistance to heat transfer at the interface, known as the interfacial thermal resistance effect. In this paper, the energy pile was simplified as a finite‐length solid cylindrical heat source, and an analytical model was established for layered heat transfer of energy piles considering the interfacial thermal resistance effect. The Laplace‐domain solutions to the temperatures in the layered ground were derived by using the finite Hankel and Laplace transforms. The Crump method was subsequently employed to numerically invert Laplace‐domain solutions to the time‐domain solutions. The proposed model was validated by comparing with an analytical solution of a homogeneous model and COMSOL numerical solution. These solutions were used to analyze the temperature response around energy piles considering interfacial thermal resistance. Finally, a parametric study was performed to explore the effects of interfacial thermal resistance and other thermal properties of the soil layer on the layered heat transfer of energy piles. [ABSTRACT FROM AUTHOR]

To calculate the surrounding soil pressure applied to shallow underground structures in layered soils, a new calculation method suitable for shallow underground works in layered soil is proposed by introducing the horizontal slice method (HSM). Through comparison with traditional methods and measured data, the rationality and accuracy of the proposed method are demonstrated. Model parameters, model assumptions, and limitations of the proposed method are also discussed. The research results find that the vertical soil pressure obtained from the proposed method is close to the results of Bierbaum's theory and method in the Chinese "Code for Design of Railway Tunnel", all showing a linear growth trend, but the lateral earth pressure derived from the proposed method shows a nonlinear distribution. The vertical pressure is linearly positively correlated with internal friction angle, cohesion, and burial depth, while it is linearly negatively correlated with the equivalent friction angle. The lateral earth pressure decreases with an increase in the internal friction angle and cohesion at the same depth, while it increases with an increasing equivalent friction angle. For layered soil, lateral stress undergoes abrupt changes of different degrees at the soil layer boundary and the burial depth boundary. [ABSTRACT FROM AUTHOR]

This paper presents a combined seismic metamaterial model based on the principle of local resonance to effectively shield Rayleigh waves at wide low-frequency bandgap in two-layered soil. In the proposed combined seismic metamaterial model, the unit-cell structure comprises two parts: a partially embedded underground concrete column and a multi-layer composite material structure enclosing the underground portion of the embedded concrete columns. By using the finite element method, the band structure and propagation characteristics of the proposed combined seismic metamaterial model are numerically investigated. Later the concrete column height effect is investigated, such as the combined seismic metamaterial model with positive gradient arrangement, negative gradient arrangement, concave arrangement, and convex arrangement. Then, the El-Centro seismic wave is considered and found that it can be considerably attenuated by the designed combined seismic metamaterial model. Additionally, this work does parameter analysis on items such as concrete density and column height. [ABSTRACT FROM AUTHOR]

The water-rich shield tunnel plays a significant role in the rapid development of underground space construction. The use of various special-shaped shield tunnels is gradually emerging for the need of functional diversity. In this study, a shield tunnel shape coefficient was proposed, and the analytical solution for the shallowest overburden thickness of special-shaped shield tunnels in double-layered soil was derived using both linear and nonlinear soil resistance models. The variables influencing the shallowest overburden thickness of shield tunnels were analyzed, and the buoyancy of shield tunnels at different construction stages was discussed. Furthermore, the solution to determine the shallowest overburden thickness of shield tunnels in multi-layered soil was presented. It was observed that the shallowest overburden thickness of shield tunnels is negatively correlated with the tunnel shape coefficient, the longest length of the cross section, and the cohesion, internal friction angle, and submerged bulk density of the soil layer. The analytical solution for the shallowest overburden thickness, considering the shear force based on the nonlinear soil resistance model, is more conducive to ensuring the anti-floating stability of the shield tunnel without excessive anti-floating capacity. [ABSTRACT FROM AUTHOR]

Field capacity (FC) is an important soil hydraulic concept in soil science and irrigation management. It is generally determined from soil water content in a soil layer when soil profile reaches a steady pressure head or negligible drainage flux from an initially saturated soil. However, the proposed criteria are mainly tested for uniform soils and vary with soil textures. To quantify FC in layered soils, a Richards equation-based model was used to describe water flow in fine-textured soils with a coarse interlayer. With calibrated soil hydraulic parameters for loam and sand from infiltration measurements, drainage from saturation was simulated in the loam with a sand interlayer. A relative drainage rate (δ) was defined as a function of water storage and drainage flux to analyze soil water status at FC. Soil water content in the upper loam layer of layered profiles was improved compared with that in the uniform loam, which was negatively correlated with buried depth but positively correlated with thickness of the sand layer for a specified δ. Under different buried depths and thicknesses, soil water content decreased with the decline of δ and decreased rapidly as δ reduced to 1 % d−1. The drainage flux at δ = 1 % d−1 changed within a range of 0.056–0.26 cm d−1, and soil water content reached to 0.278–0.346 cm3 cm−3, which accounted for 70–87 % of the saturated water content of loam. Although the FC in the upper fine-textured soil layer varied for different buried depths and thicknesses of coarse interlayer, the proposed dynamic method is reliable and universal to estimate the FC in the above layered soils at δ = 1 % d−1. An empirical equation was also developed to calculate the FC in fine-textured soils with different buried depths and thicknesses of a coarse interlayer based on the critical δ value.

This paper investigates steady infiltration problems involving periodic channels in two-layered soil with the presence of root-water uptake. The problems are governed by a set of Richards' equations accompanied by boundary interface conditions. To address these problems, we transform the system of Richards' equations, along with the corresponding boundary conditions, into a set of steady diffusion-convection equations with transformed boundary conditions. The mathematical model is then tackled through a numerical approach utilizing the Iterative Dual Reciprocity Method (IDRM). Through this numerical method, we obtain solutions that describe the distribution of soil water potential and hydraulic conductivity within the soil. The outcomes of this study shed light on the influence of soil texture and saturated hydraulic conductivity on the values of soil water potential and hydraulic conductivity. [ABSTRACT FROM AUTHOR]

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This paper represents both experimental and numerical study of the strip footing resting on two layered reinforced c-ϕ soil. Small scale shake table tests are conducted to evaluate the different parameters like vertical settlement, (Root mean square amplification) RMSA factor, and total stress at different levels of layered soil. Test results revealed that increase in moisture content the parameters like vertical deformation, RMSA are increasing and after the optimum moisture content the above parameters are decreasing. Further addition of moisture content increases the above parameters. Inclusion of reinforcement tends to reduce all the above parameters but is more effective in reduction of maximum RMSA amplification factor. From the numerical result, it is seen that by increasing the moisture content vertical deformation and RMSA factor is increasing by 5-10%. To verify the results obtained from the present study, a numerical analysis is done by using PLAXIS 2D and the acceptability of model is discussed. It is observed the differences between experimental and numerical results are varying from 2-6%. [ABSTRACT FROM AUTHOR]

Punch-through failure may occur when the spudcan is installed in layered soil, which can result in a detrimental effect to the jack-up unit and jeopardize personnel. This paper introduced a practical case of spudcan punch-through which occurred in a kind of multi-layer soil which has a thin stiff layer and a transition layer locating between soft layers. The existence of the transition layer blurs the difference of soil strength. To explore the failure mechanism set behind the field case, LDFE analyses were conducted with the Coupled Eulerian-Lagrangian (CEL) method. The results indicated that the failure of soil changes between three failure mechanisms of general shear, punch-through and squeezing with the penetration of spudcan. The transition point of failure mechanism can be identified through the depth of failure surface based on the LDFE results. According to the failure mechanism, a modified approach was set out in estimating the spudcan penetration resistance in the multi-layer soil, which matches the field data well on the basis of the soil strength obtained by laboratory element tests. [ABSTRACT FROM AUTHOR]

The pore water can usually flow through the horizontal electrodes, resulting in the top sand layer and the bottom unelectroosmotic layer inevitably affecting the consolidation process of the electroosmotic layer. However, the traditional assumption of the fully drained or undrained electrode boundaries is unable to reflect these boundary effects. In this study, one‐dimensional analytical models for electroosmotic consolidation of the layered soil systems considering the boundary effects of horizontal electrodes are proposed. The solutions for the models are derived using the separate variable method and Laplace transform method. The rationality of the one‐dimensional model is also illustrated by comparing it with the results produced by the two‐dimensional model and the accuracies of the solutions are verified through a series of analytical and numerical validation examples. Parametric studies are conducted to investigate the effects of the sand layer and the unelectroosmotic layer on the consolidation process. Results show that both the sand layer and the unelectroosmotic layer may significantly delay the consolidation progress. The time factor corresponding to 90% average degree of consolidation (Tv_90%U*) can increase by over 1.5 times in comparison with the model without a sand layer when the permeability coefficient ratio of the subsoil to the upper layer reaches 10. The delayed effect is particularly pronounced when the thickness of the unelectroosmotic layer with higher compressibility is relatively larger, potentially resulting in a tenfold or even greater increase in Tv_90%U*. [ABSTRACT FROM AUTHOR]

The traditional method for analysis and design of laterally loaded piles with non-circular cross-sections such as rectangular, H-shaped, and X-shaped piles involves the simplification of converting the non-circular pile to a circular pile with equivalent second moment of inertia. A rigorous semi-analytical method is developed for calculating the response for laterally loaded piles with arbitrary non-circular cross-sections in multi-layered elastic soil without using any simplification regarding the shape of the pile cross-section. The governing differential equations for the pile–soil system are obtained using the principle of virtual work. The soil displacements around the pile are described as products of separable functions that are compatible with horizontal pile movement. As a result, the three-dimensional (3 D) boundary value problem (BVP) is described by a fourth-order linear ordinary differential equation (ODE) governing horizontal pile displacement and second-order partial differential equations (PDEs) governing soil displacements. New solution techniques for the ODE and PDEs are proposed, and the accuracy of the present method is verified by comparing the predicted pile and soil responses with the corresponding results of equivalent 3 D finite element method. The effects of pile cross-section shape and lateral loading direction on the pile and soil responses are highlighted through a series of parametric analyses. [ABSTRACT FROM AUTHOR]

The efforts made all over the world towards the fact of decreasing the environmental pollution have been enormously demanding now a days. Therefore the increase in caution towards a sustainable environment has restricted the use of materials which may have huge impact towards environment pollution. The geosynthetic is a cost-effective and corrosive resistant material which can be used in the most exposed conditions to mitigate the anticipated excessive settlement in case of soft soil. The present study investigated the behaviour of a geocomposite material in a layered soil system. Three types of geocomposite were manufactured by changing the tensile stiffness of the components viz. GCBX-40, GC-BX-60, and GC-BX80. The basic configuration of every geocomposite was same and was made by sandwiching a geotextile layer in between the two geogrid layers which have significantly improved the surface frictional resistance due to the increase in the surface cover ratio and also the improvement in the interlocking effect on the soil grains due to the geogrid layers on both sides. The various layouts of geocomposite were introduced in this study besides the general planar layout and it was found that the confinement effect was increased with in the soil layers. Therefore, the cohesion (c) between the soil grains and the frictional angle (ϕ) was modified due the increased confinement which not only improved the bearing capacity factor but the settlement reductions factor was also improved. The results revealed that the load carrying capacity was improved from 33.8 to 40.59% by using different types of geocomposite. [ABSTRACT FROM AUTHOR]

This paper presents a mathematical model for the analysis of axially‐loaded end‐bearing piles embedded in a two‐layer elastic soil deposit. The governing equations of the soil layers surrounding the pile are cast by means of a Tajimi‐type continuum formulation, and this allows deriving a closed‐form expression that provides the frictional stresses that develop at the soil‐pile interface. The pile is treated as two virtual one‐dimensional elastic rods, and pile displacements are obtained by solving a system of linear equations that results from considering the boundary and continuity conditions. This results in improved efficiency compared to existing Tajimi‐based solutions for piles in layered soil, at no expense of accuracy. The model is used to study the effect of the relative stiffness of the soil layers on the serviceability behavior of axially‐loaded piles, and drawn conclusions of practical importance. [ABSTRACT FROM AUTHOR]

• A fractional-order viscoelastic model is used to simulate soil. • The time variation of engineering load is considered. • The layered property of soil is considered. • The influence of the bottom rock on the soil is considered. • The recovery of settlement after unloading is analyzed. Time-varying loading is a frequently encountered loading type in geotechnical engineering. As the deformation of viscoelastic soil is related to its loading history, studying the viscoelastic problems under time-varying loads has important practical engineering significance. In this paper, the stress and displacement of a layered soil with fractional-order viscoelastic model under time-varying loads were solved using the complex variable method and the corresponding principle. Under the assumption of quasi-static and linear elasticity, this paper derives the quasi-static elastic solutions of a layered soil under time-varying strip loads. By introducing the fractional-order viscoelastic model and using the corresponding principle, the Laplace-domain analytical solutions are obtained. Finally, numerical methods are utilized to perform the Laplace inverse transform and obtain the solutions in the physical domain. The correctness of this paper is validated by comparing the numerical results with the ANSYS software, as well as by comparison with previous literature. Based on the experimental data, the material parameters of frozen soil at two temperatures are fitted. The settlement patterns of soil under two engineering loads were analyzed through case studies. By controlling variables, the influence of parameters of the fractional viscoelastic model on elastic aftereffect was investigated. [ABSTRACT FROM AUTHOR]

This paper presents a numerical model, called consolidation settlement - elastic-viscoplastic (CS-EVP), for the consolidation of layered soft soils, including soil self-weight and time-dependent compressibility effects. CS-EVP was developed using the piecewise-linear method for large-strain consolidation and elastic-viscoplastic model for time-dependent soil compressibility. The model accounts for vertical strain, soil self-weight, nonlinear hydraulic conductivity and compressibility, nonlinear creep with limited creep strain, and time-dependent surcharge and/or vacuum loading for layered heterogeneous soils. The accuracy of CS-EVP is verified by comparing calculated values with the results from finite-element simulations and a large-scale laboratory vacuum consolidation test of soft soil slurry. Lastly, simulated settlements and excess pore pressure profiles are compared with field measurements for embankment loading in Väsby, Sweden. The results indicate that CS-EVP provides good estimates of long-term large-strain consolidation under both laboratory and field conditions. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study provides a solution for determining stress and displacement measurements of layered soil under the interaction of two adjacent strip footings by using conformal transformation methods (CTMs) in complex variable functions. Using the CTM, this research maps each layer of soil to a unit circle and calculates two single-valued analytic functions of each layer based on continuous conditions and boundary conditions to obtain the stress and displacement fields of the entire soil. The results were verified after being compared with the numerical solution of the Analysis Systems (ANSYS) finite-element software. In addition, this research uses two layers (as an example) to analyze influences of clear spacing of the footings and shear modulus of the soil on the interaction of two strip footings, as well as the influence of the center spacing of the footings and shear modulus of the bottom layer on differential settlements. The results indicate that an increase in the clear spacing of the footings and shear modulus of the soil sublayer greatly reduces the interaction between the two footings. Moreover, the differential settlement will increase with the center spacing, but will not vary with a changing shear modulus of the sublayer soil. [ABSTRACT FROM AUTHOR]

This paper presents a case study on incidents of offshore pile running in layered soils. The study provides a detailed description of the seabed soil data, pile driving records, and field surveillance video observations. Three-dimensional large deformation finite element (LDFE) analyses were conducted to retrospectively analyze the incidents, considering the remoulding of seabed soil and degradation of the pile-soil interface in the LDFE modeling. By comparing the field observations with the LDFE analysis, the mechanism of pile running was discussed, with a focus on investigating the pile penetration resistance in each layer. The study revealed that pile running in layered soils primarily resulted from a significant reduction in pile base resistance when transitioning from a strong layer to an adjacent weak layer. To further investigate the pile running mechanism in layered soils, a parametric study on the strength variation of adjacent soil layers and its influence on pile base resistance was conducted. Lastly, a simplified prediction model of pile base resistance, suitable for assessing the risk of pile running in layered soils, was proposed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Purpose: The purpose of this article is to check if and how hammer experiments can be applied to the prediction of railway vibration. Methods: The propagation of ground vibrations is theoretically analysed with frequency-wavenumber and simplified methods. Experimental methods are presented which can characterise the site-specific ground vibrations by wave velocities, stiffness and damping. Measurements with hammer and train excitation have been performed at several sites. Results: The one-third octave spectra show the stiffness-dependent amplitudes and the low- and high-frequency filter effects due to the layering and the damping of the soil. Specific train effects, an additional high-frequency filter, the sleeper passage frequency, and an amplified mid-frequency component can be clearly found. The attenuation with distance is analysed in detail where the theoretical exponential and the empirical frequency-dependent power law are considered. Hammer and train excitation show the same site-specific effects which are mainly due to the stronger or weaker damping of the soil. The train attenuation is generally weaker than the hammer attenuation. The attenuation exponent of the power law, which is strongly dependent on the site and the frequency, is reduced for the train vibration by 0.3–0.5 in agreement with the theory. Reasons are discussed for the overall power law and for the dominating mid-frequency component. Conclusion: Therefore, it can be concluded that hammer experiments can well be used for the prediction of train vibrations. [ABSTRACT FROM AUTHOR]

The present study proposes a new finite element methodology to analyse the behaviour of flexible combined pile–raft foundation (CPRF) situated in layered soil, in a displacement-based framework. The soil medium is idealised as an advanced elastic Pasternak medium and the piles and raft are modelled as bar and plate element, respectively. The two components of CPRF are analysed simultaneously and displacement compatibility is satisfied at the pile–raft junctions. A number of soil–structure interaction factors, which govern the behaviour of CPRF, are suitably subsumed in the analysis scheme. The proposed method is validated with available analytical and experimental studies. Further parametric studies, investigating the effects of soil layering and raft flexibility on the behaviour of CPRF, are explored. It is observed that the load sharing proportion between the components and the raft deformation pattern depend upon the thickness and position of the soft soil layer in a multilayered soil system. The thickness of the flexible raft plays a pivotal role in determining the behaviour of CPRF, founded in a multilayered soil profile. Thus, this research manifests notable advancement in understanding the behaviour of flexible CPRF in layered soil. [ABSTRACT FROM AUTHOR]

The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification.

This paper analyzes a piled-raft foundation on non-homogeneous soils with variable layer depth percentages. The present work aims to perform a three-dimensional finite element analysis of a piled-raft foundation subjected to vertical load using the PLAXIS 3D software. Parametric analysis was carried out to determine the effect of soil type and initial layer thickness. The parametric study showed that increasing the relative density from 30 % to 80 % of the upper sand layer and the thickness of the first layer has led to an increase in the ultimate load and a decrease in the settlement of piled raft foundations for the cases of sand over weak soil. In clay over weak soil, the ultimate load of the piled raft foundation was increased, and the settlement decreased by increasing the clay cohesion of the upper layer from 20 kPa to 70 kPa. It was observed that the load shared by the raft was very effective when using dense sand in the upper layer. In the case of dense sand over stiff clay, the percent of load carried by the raft is (30-40) %. Although, for the case of stiff clay over soft clay, the load percentage was almost constant (16-20) %. While for other issues, the sharing load of raft foundation was close and had the same behavior, the load carried by raft is between (8-12) %.

This paper theoretically estimates the dynamic pile–soil interaction and the group efficiency factor for pile group in layered soil through energy‐based method. The vertical dynamic interaction of partially embedded single piles and their surrounding layered soil is analytically deduced from Hamilton's principle. Combined with a series of numerical simulations, the soil attenuation factor from energy method is modified for adapting to the wave speed variation in various layers. Then, the pile‐to‐pile interaction factor is directly solved with the help of the transfer‐matrix method. The dynamic governing equation of pile group with an elevated rigid cap is established by superposing the pile‐to‐pile interaction factors. Finally, the dynamic impedance of pile group is obtained and derived into a group efficiency factor. Compared with the plane strain method, this present method can produce a more suitable soil attenuation factor and a dynamic interaction factor at low frequency range, which is exploited for practical engineering design. The effects of subsoil layer, subsoil layer, and unembedded pile segment on group efficiency factor are investigated. The results show that the real part of group efficiency factor decreases at high frequency range for a small pile spacing, which may be detriment to the pile group capacity. Besides that, the combined effects of unembedded segment and weak surface soil on group efficiency factor are highlighted. [ABSTRACT FROM AUTHOR]

In this study, based on the wave function expansion method and exact stiffness method (ESM), an analytical model for a circular lined tunnel embedded in the layered soil under seismic waves is established. For convenience, the wave field in the layered‐soil‐tunnel (LST) system is divided into three parts, that is, the free wave field and scattering wave field in the layered soil, as well as the transmitted wave field in the lining. The free wave field in the layered soil is determined by the ESM for the layered soil. The scattering wave field in the layered soil is further decomposed into three parts, namely, the principal and complementary wave fields in the soil layer with the tunnel (the tunnel layer) as well as the modified wave field occurring in the other soil layers. These scattering wave fields are represented by the corresponding principal, complementary, and modified wave functions, respectively. The principal wave functions associated with the direct cylindrical waves emanated from the tunnel are represented by the Hankel functions. The complementary and modified wave functions correspond to the additional responses of the tunnel layer and the other soil layers due to the direct cylindrical waves from the tunnel, and can be obtained by expanding direct cylindrical waves into plane waves together with the application of the ESM. The transmitted wave field in the lining is simply represented by two kinds of Bessel functions. With the aforementioned wave field representations, the boundary value problem for the LST system under seismic waves is formulated. Based on the proposed analytical model, some numerical results and corresponding analyses are presented. Presented numerical results indicate that the dynamic stress concentration factor (DSCF) associated with the stiffer tunnel layer is usually larger than that associated with the softer tunnel layer for the incidence of plane P waves with not very low frequencies, while the circumstance for the incidence of plane SV waves shows an opposite tendency. [ABSTRACT FROM AUTHOR]

The determination of seismic passive earth pressure resistance is of utmost importance during the analysis of geotechnical structures. In the present study, seismic passive earth pressure coefficient for caisson embedded in n‐layered soil is computed using modified pseudo‐dynamic method. Limit equilibrium method of analysis considering poly‐planar failure wedge has been adopted in the study and parametric variation of geometry of failure wedge has also been studied. The current study proposes formulation for variation of horizontal and vertical seismic acceleration profile with depth through various layers and studies the effect of number of layers, relative depths of various layers and relative soil friction angle in those layers, soil‐wall friction angle, horizontal and vertical seismic acceleration coefficients and normalized width of caisson. The study has been extended for submerged soil and the effect of excess pore pressure has been investigated. The results of the present study have been compared with previous theoretical studies and found to be in good agreement. It is observed that the extent of failure wedge formed in front of caisson increases with increasing soil friction angle, soil‐wall friction angle, horizontal seismic acceleration coefficient and width of caisson. [ABSTRACT FROM AUTHOR]

A two-dimensional plane-strain finite element analysis based study is conducted to investigate the overall response of skirted strip footing resting on layered soil media comprising a loose sand layer overlaying a dense sandy stratum. The influence of different parameters associated with the foundation system, namely the skirt depth, embedment depth of footing, depth of overlying soil layer and its friction angle, are inspected on the load carrying capacity of skirted strip footing. The displacement mechanism beneath the skirted strip footing is also investigated for different depths of overlying soil layer. Finally, the generated axial forces and bending moments in the skirt are analysed for various cases. It is observed that the load carrying capacity, total displacement and shear stress of skirted strip footing are negligibly affected by the underlying dense sandy layer as its depth is superseded by the thickness of the overlying layer. It is also found that the load carrying capacity of skirted strip footing increased by 34% per 5° increase in the friction angle of the overlying layer. Increase in the skirt depth also exhibited reasonable increase in the load bearing capacity by providing additional confinement to the soil beneath the footing. [ABSTRACT FROM AUTHOR]

The p-y curve method can be used to describe the stress–strain relationship of soil under elastic, elastoplastic, and plastic states, and is more accurate than other methods in dealing with the nonlinearity of pile–soil interaction. However, the p-y curve method also has several limitations. First, when constructing the p-y curve, undrained shear strength Cu is taken to be constant, and the diversity of soil layers around the pile side are also not considered. Second, in the analysis of the internal forces and deformation of the pile, the influence of the vertical load from the top of the pile and the self-weight of the pile, are both ignored. Third, in the analysis of internal forces and deformation, the pile side soil is set equivalent to a homogeneous soil layer, and the layering of the soil is not considered at all. In order to study the nonlinear problem of internal forces and deformation of a single pile in layered soil in greater detail, this paper analyzes a calculation model based on Wang's calculation model, and compares several commonly used p-y curve calculation models. An internal force and deformation analysis model for a laterally loaded single pile, that explicitly considers the second-order effect is then established, by considering the differences between p-y curves of different soil types, as well as the change in Cu with depth. The differential equation of pile deflection for a single pile in layered soil is also presented, together with the corresponding finite differential solution algorithm program. This model was validated using a horizontal load test of a pile, and comparison of the calculated results with the measured results shows that the method outperforms existing p-y curve methods for deformation and internal force analysis of horizontally loaded piles. [ABSTRACT FROM AUTHOR]

Capillary rise tests were conducted on soil columns containing of three layers of sandy soils with coarser over finer over coarser sandy soil to investigate the effect of the relatively finer soil interlayer. The capillary rise height, rate, and water distribution were observed in laboratory tests of four layered soil columns, with two homogeneous (without the interlayer) soil columns serving as the controls. The final maximum height of the capillary rise in the soil column with the interlayer was larger than that of the column without the interlayer when the interlayer was laid around the water entry value of the underlying soil. The water content was not continuous in the entire soil profile with the interlayer, and a small matric suction gap was observed in the relatively fine soil between the soil column with and without the interlayer. [ABSTRACT FROM AUTHOR]

The pattern of root distribution in layered soils is one of the significant issues in the calculations of soil water and irrigation management and planning. The objective of this study was to determine the pattern of root distribution of soybean in layered soils and its effect on water uptake. The research was conducted in a completely randomized design with 15 treatments consisting of three different textures of soil (light, heavy, and medium) in four replications. The pattern of root distribution was monitored by the sampling of columns at the end of the growth period of the soybean. It was observed that the presence of the layer with medium texture has led to better plant development and growth after comparing the treatments in terms of plant growth. In general, root length density decreased with increasing soil depth, except in cases where there were different layers of soil, and root length density takes place in the following order: root length density in layers with medium texture≥ heavy texture≥ light texture. The rate of root water uptake rate was highest in the sandy layers, intermediate in clay, and lowest in loamy texture. Also, the rate of root water uptake rate increased significantly with increasing depth regardless of treatments. It can be concluded that the pattern of root distribution and plant growth is significantly affected by soil texture and its stratification. [ABSTRACT FROM AUTHOR]

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A simplified approach to study the dynamic interaction between the pile group and two-layered soil under scour is presented. • The model is developed by combining the finite element method (FEM) and analytical layer element method (ALEM). • The effects of the scour type, scour depth, scour width and soil's layered property on the dynamic behavior of pile groups are examined. Pile groups for the bridge and jacket foundations in the marine or traffic geotechnical engineering are significantly influenced by the current scour in service. Under the effects of scour and dynamic load, the capability of the pile foundations to resist deformation is reduced and thus causes structural failure. This paper presents a FEM-ALEM coupling approach to study the dynamic interaction between a pile group and layered soils under scour condition. Behaviors of the pile group are analyzed by applying the finite element method. Fundamental solutions of the layered soils under scour condition are obtained by adopting the analytical layer element method. Comparisons with existing solutions are performed to confirm the correctness of the present approach, and numerical examples are provided to discuss the effects of the scour type, scour depth, scour width and layered property of soil on the dynamic behaviors of the pile group. The present coupling approach can be used to evaluate the responses of a pile group embedded in layered saturated soils under scour due to a vertical dynamic load. [ABSTRACT FROM AUTHOR]