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Full-Text Articles in Geotechnical Engineering
Prediction Of Field Sand Liquefaction Caused By Earthquake By Optimum Seeking Method, Du Jian, Zhang Lianyang
Prediction Of Field Sand Liquefaction Caused By Earthquake By Optimum Seeking Method, Du Jian, Zhang Lianyang
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
There are many uncertain factors influencing the field sand liquefaction induced by earthquake, therefore, the predictions of available methods are usually unsatisfactory. In this paper, a new way is developed, i.e., according to the available field sand liquefaction data, the influencing factors are optimized by optimum seeking method, then the prediction is made on the optimized results. By this method, 20 field cases are predicted and the correct rate is 95%. It proves that the suggested method is effective and feasible.
Prediction Of Liquefaction Behaviour Of Cohesionless Soils, Nakul Dev, Shenbaga R. Kaniraj
Prediction Of Liquefaction Behaviour Of Cohesionless Soils, Nakul Dev, Shenbaga R. Kaniraj
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In order to mitigate earthquake effects occurring because of soil liquefaction, it is essential that the characteristics of soil deposits prone to liquefaction be reliably assessed. The present paper is an attempt in this direction. Liquefaction behaviour of five sands of different gradation characteristics is evaluated under cyclic simple shear conditions and the results have been used to predict the behaviour of Badarpur sand. Fineness Modulus, and a grain size and gradation factor have been used to predict the cyclic strength. The predicted behaviour is then verified by carrying out simple shear tests on Badarpur sand. As the predicted strength …
Preliminary Research In Predicting Liquefaction Potential Of Saturated Soil Using Vs, Qc, Chang Hong
Preliminary Research In Predicting Liquefaction Potential Of Saturated Soil Using Vs, Qc, Chang Hong
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In the paper, first describes the condition of the testing ground, then the circumstances of test (pressed wave velocity test & static cone penetration test, or vs & SCPT) is presented, i.e., the improvement of SCPT equipment make the test (Vs & SCPT) be in progress simultaneously, meanwhile, the SPT is conducted so that relations are found among the testing data. The results of tests are shown in this paper, the relative curves of sandy soil and sandy loam (Vs & N, qc & N) are gained respectively by way of analysing the test data, and experiential formulas of the …
Sand Liquefaction With Initial Pore Pressures, Hong Xia
Sand Liquefaction With Initial Pore Pressures, Hong Xia
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Cyclic triaxial tests are conducted on saturated sand samples with different values of initial pore pressures existed throughout the whole process of tests. It is found that the presence of such initial pore pressures (or static hydraulic pressures) tends to increase the liquefaction resistance of the sand samples. The effects of the degrees of saturation are also investigated by conducting another four sets of the cyclic triaxial tests on sand samples with different levels of saturation, since the degree of saturation is a very closely related factor which could be changed by the presence of the initial pore pressures. The …
Semi-Analytical Iteration Algorithm Of Seismic Pore Pressure, Zhang Jianmin, Xie Dingyi
Semi-Analytical Iteration Algorithm Of Seismic Pore Pressure, Zhang Jianmin, Xie Dingyi
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this paper a semi-analytical iteration method for predicting the seismic pore-water pressure generation and dissipation in saturated sand layers is suggested. The fundamental formulae including three general analytical solutions under the condition of the 1-D, 2-D, and 3-D dissipation and the calculation principle are briefly presented, and then the suggested method is used in predicting the generation and dissipation of seismic pore water pressure in the 1-D saturated sand layers as an example. The suggested method provides the possibility to consider at a certain extent the change characteristics in permeability and volumetric strain of sand during the seismic action …
Settlement Calculations Of Clay Layers Induced By Earthquake, Hiroshi Matsuda, Eiichi Hoshiyama, Sukeo Ōhara
Settlement Calculations Of Clay Layers Induced By Earthquake, Hiroshi Matsuda, Eiichi Hoshiyama, Sukeo Ōhara
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A procedure to calculate the seismic settlement of clayey layers is developed based on the strain-controlled cyclic simple shear test results. By using this procedure the seismic ground settlements are estimated and also the results are compared with the observed ones. In the calculations, six types of accelerogram are used. As a result of estimations, following conclusions are obtained. (1) In the case of a horizontal soil layer of 5 m in height, the settlements are in the range from 3 to 6 cm for a maximum acceleration of about 340 gal. (2) In the case of clay deposits in …
The Characteristics Of Residual Strength Of Silt Under Liquefaction Conditions, H.-C. Fei, F. Lu
The Characteristics Of Residual Strength Of Silt Under Liquefaction Conditions, H.-C. Fei, F. Lu
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Silt soil is defined as a soil whose fine particles (D50 < 0.005mm) content is from 3% to 15%. The Tangshan earthquake of 1976 had a magnitude of 7.8 and caused the liquefaction of silt soil in large areas in Tianjin City. The seismic intensity at Tianjin was 8° in downtown. Currently the same criterion for initial liquefaction is applied to silt and sand, e.g., the development of pore pressure, u, equal to the effective confining pressure σ0'. However, in silt residual strength still exists because of cohesion due to the finest of the particles even when u = σ0' due to shaking. The authors employed a superimposed ring shear device to study the characteristics of residual shear strength of silts with different fine particle contents and with various pore pressure ratios, u/ σv' under both dynamic and static loads.
Utilization Of Cone Penetration Test To Evaluate Liquefaction Potential Of Soils, Teparaksa Wanchai
Utilization Of Cone Penetration Test To Evaluate Liquefaction Potential Of Soils, Teparaksa Wanchai
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A new practical method for evaluation of soil liquefaction by using the Cone Penetration Test (CPT) was proposed. The critical normalized cone resistance, (qcl)cr was presented in terms of cyclic stress ratio, τ/σ0' , and mean grain size of soils, D50. Based on our proposed CPT-based liquefaction assessing correlation, we presented the typical examples of the use and application of CPT to assess liquefaction potential of past earthquake as well as to verify the effectiveness of soil improvement counterrneasured to increase liquefaction resistance of soil.
Vibrations Of An Inhomogeneous Layer, Hasan Engin, M. Ertac Erguven
Vibrations Of An Inhomogeneous Layer, Hasan Engin, M. Ertac Erguven
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this study, we have investigated vibrations of an inhomogeneous layer which is forced along its bottom. The shear modulus of the layer varies with depth. Considering the layer thickness is constant and the forcing displacement at the bottom is horizontal, shear vibrations will be studied. The solution of the governing equation has been carried out by using Bessel functions including unknown parameter q. Frequencies which make the amplitude of vibrations infinite are called natural frequencies of the layer. Variational of the natural frequencies and the shape of the shearing waves along the thickness of the layer have been investigated …
Displacement Based Design Of Retaining Walls, Raj Siddharthan, Prakash K. Gowda, Gary M. Norris
Displacement Based Design Of Retaining Walls, Raj Siddharthan, Prakash K. Gowda, Gary M. Norris
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A relatively simple rigid plastic model to study deformation behavior of rigid retaining wall is outlined. Both sliding and tilting modes of deformation are included. The study clearly reveals that wall movement caused by tilting can be substantial. But for high values of foundation soil friction angle, the tilting component of deformation can be omitted. Since the wall movement is affected by the characteristics (strength and frequency) of the excitation history, a number of excitation histories should be considered in retaining wall designs.
Dynamic Earth Pressure Distribution Behind Retaining Walls, D. M. Dewaikar
Dynamic Earth Pressure Distribution Behind Retaining Walls, D. M. Dewaikar
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The point of application of dynamic active thrust and its distribution are computed using the method of slices and criterion of maximization of overturning moment of the active thrust. The computations show that point of application of the dynamic thrust is significantly influenced by such factors as wall friction and acceleration coefficients. Horizontal accelerations coupled with positive vertical accelerations (acting downwards) have the effect of moving the point of application closer to the wall base. The combination of horizontal acceleration with negative vertical acceleration produces exactly the reverse effect and generates more overturning moments even though the magnitude of corresponding …
Effective Stress Analysis Of A Sheet Pile Quaywall, Susumu Lai, Tomohiro Kameoka
Effective Stress Analysis Of A Sheet Pile Quaywall, Susumu Lai, Tomohiro Kameoka
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In 1983, Nihonkai Chubu Earthquake of magnitude 7.7 hit northern part of Japan. The earthquake caused damage to quaywalls at Akita Port located about 100 km from the epicenter. The damage was associated with the liquefaction of backfill sand. In order to analyze the mechanism of the damage, soils are taken from the site for laboratory tests. The record of the earthquake motion is digitized. Based on these investigations, a two dimensional effective stress analysis is conducted. The model used in this study consists of a multiple virtual simple shear mechanisms oriented in arbitrary directions. The results of the effective …
Seismic Design Of Rigid Underground Walls In New England, Cetin Soydemir
Seismic Design Of Rigid Underground Walls In New England, Cetin Soydemir
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The Mononobe-Okabe equation is still widely used in design practice to estimate earthquake induced soil pressures against earth retaining structures without differentiation of the lateral yielding or non-yielding character of the structure. Where these structures are rigid and non-yielding because of structural restraints (e.g., basement walls, bridge abutments, underground transportation, hydraulic and sanitary structures) the use of Mononobe-Okabe equation would not be appropriate and would be generally unsafe. Alternate design recommendations are proposed, based on the results of recent analytical and experimental studies by other researchers, for a nominal design earthquake expected to be representative of the New England seismicity.
Seismic Earth Pressures Against Structures With Restrained Displacements, P. Ortigosa, H. Musante
Seismic Earth Pressures Against Structures With Restrained Displacements, P. Ortigosa, H. Musante
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A simplified kinematic method to compute seismic earth pressures against structures with restrained horizontal displacements is described. The retaining structure has a linear elastic behavior and the retained soil is considered linear as well as a nonlinear material. Seismic pressures for different maximum free field accelerations were obtained by applying free field horizontal displacements at the base of the interaction springs connecting the soil and the retaining structure. For perfectly rigid structures without horizontal displacements and linear retained materials, seismic pressures obtained with the simplified kinematic method are compared with those obtained using elastic models; for nonlinear retained soils comparisons …
Stability Of Fiber Reinforced Sand Retaining Walls, Masami Fukuoka, Kakuhiro Nakayama, Shun-Ichi Lhara, Kiyohiro Okedoi, Ken-Ichirou Ozaki
Stability Of Fiber Reinforced Sand Retaining Walls, Masami Fukuoka, Kakuhiro Nakayama, Shun-Ichi Lhara, Kiyohiro Okedoi, Ken-Ichirou Ozaki
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A ten meter high retaining wall made by sands reinforced with continuous fibers was constructed in 1988. Thickness of the retaining wall was 1 mat the top and 2.5 m at the bottom, and the slope was 63° at the face and 71° at the back. Earth pressure acting on the wall, displacements of the face, settlements of the fill and acceleration of the retaining wall were measured. During the construction, around the third height of the wall was displaced 15 cm in a forward direction. At the time of an earthquake, the values of the maximum horizontal acceleration at …
Study And Design Of Earth Reinforced Structures Under Dynamic Efforts, Ammar Dhouib, Grant Knochenmus
Study And Design Of Earth Reinforced Structures Under Dynamic Efforts, Ammar Dhouib, Grant Knochenmus
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper aims at giving a synthesis of recent design methods of earth reinforced structures submitted to dynamic actions. In the first instance, we intend to tackle a comparative study on scaled - down models and on real works in reinforced earth. This study is led by the finite elements method. Secondly, we propose a simple method to design reinforced earth structures.
A Hybrid Model For Soil-Foundation Compliance, Chin-Hsu Lin, Teresa M. Adams
A Hybrid Model For Soil-Foundation Compliance, Chin-Hsu Lin, Teresa M. Adams
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper describes a hybrid method that may be used to model the dynamic responses of multiple rectangular foundations resting on a homogeneous, viscoelastic stratum and excited by harmonic waves. The hybrid analysis described in this paper combines the dynamic stiffness and finite element methods. The method uses equivalent area disk loads for Green's functions at the soil surface. The dynamic stiffness method is used to obtain the stiffness matrix of the soil medium and the finite element method is used to obtain the stiffness matrix of surface foundations. The stiffness of the entire soil-structure system can be obtained using …
A Hybrid Modeling Of Soil Structure Interaction Problems, Celso Romanel, Tribikram Kundu
A Hybrid Modeling Of Soil Structure Interaction Problems, Celso Romanel, Tribikram Kundu
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A hybrid method is proposed in this research for dynamic soil-structure interaction analysis of embedded structures within a multilayered elastic half-space. A near field region, containing the structure and a portion of soil surrounding it, is modeled by finite elements while the far field formulation is obtained through the classical wave propagation theory based on the assumption that the actual scattered wave fields can be represented by a set of line sources located at a depth corresponding to the center of mass of the structure under investigation. Traction reciprocity between the two regions is satisfied exactly while displacement continuity across …
Analysis Of Pile-Soil Dynamic Interaction By Combination Of Bem And Fem, Shiming Wu, Yuanqiang Cai, Yunmin Chen, Longzhu Chen
Analysis Of Pile-Soil Dynamic Interaction By Combination Of Bem And Fem, Shiming Wu, Yuanqiang Cai, Yunmin Chen, Longzhu Chen
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A hybrid method, in which soil media is modeled by 3-D boundary elements and the pile by 1-D finite elements, for an analysis of dynamic pile-soil interaction is investigated. A new series of equations and an efficient method to deal with singularity of integrals are presented. Several effects including pile length, stiffness of the pile and surrounding soil on dynamic response are studied. Finally, the characteristics of impaired and intact piles are investigated and compared; and some case studies are presented.
Behaviour Of Cyclically Loaded Model Piles In Soft Clay, R. D. Purkayastha, S. Dey
Behaviour Of Cyclically Loaded Model Piles In Soft Clay, R. D. Purkayastha, S. Dey
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Instability studies on offshore piles has been carried out to a very limited extent. Cyclic loading resulting from wave action is a very common phenomenon for such piles. Continuous cycling {both vertical and lateral) presumably leads to substantial degradation in pile-soil response, the ultimate result of which could be disastrous. Over the last decade and a half, some work has been done to study the pile-soil interaction behaviour under repeated cyclic loading. This paper aims to highlight and discuss the salient features and the important observations of extensive model tests on piles subjected to vertical cyclic load. The degradation of …
Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming
Dynamic Response Of Flexible Foundations On Multilayered Medium, Wang Fuming
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The dynamic response of flexible strip-foundations placed on a viscoelastic multi-layered medium under conditions of plane strain and subjected to harmonic excitation is studied in this paper. A semi-analytic model is developed to determine the dynamic flexibility matrix of the medium, and the spline finite element method is employed to treat the foundation. The two methods are appropriately combined through equilibrium and compatibility considerations at the soil-foundation interface. Numerical results describing the influence of the non-homogeneity of the soil medium on the compliance are presented, and the effects of the relative stiffness Kr on the foundation response are briefly discussed.
Dynamic Response Of Foundations On Two-Parameter Media, A. Alvapplllai, M. O. Faruque, M. Zaman
Dynamic Response Of Foundations On Two-Parameter Media, A. Alvapplllai, M. O. Faruque, M. Zaman
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A finite element algorithm is presented to analyze the dynamic response of rectangular foundations resting on an elastic medium. The foundation is modeled by rectangular thin plate elements and the supporting elastic medium is represented by the two parameter model proposed by Vlasov. The natural frequencies of the foundation-elastic medium are investigated. A parametric study is conducted to examine the effects of the edge and corner forces, that are accounted for in the two parameter model, on the dynamic response of a plate subjected to a moving vertical force.
Earthquake Resistant Piles Reinforced With Ground Walls, Yoshiaki Nagataki, Hiroaki Senoo
Earthquake Resistant Piles Reinforced With Ground Walls, Yoshiaki Nagataki, Hiroaki Senoo
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A method for reducing earthquake load acting on piles by means of ground walls installed around pile foundation is proposed. First, a shaking table test was carried out. Test specimens are 1/40 scale structural models, which consist of soil, piles and a building with or without ground walls. The pile head moment of the specimens with ground walls show only 60% of that of the specimens without the ground walls. An FEM analysis was carried out for both cases and the results were compared with the test results. The comparison showed a good agreement. Furthermore, a simplified calculation method is …
Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna
Evaluation Of Seismic Soil-Structure Interaction (Ssi) By Different Approaches, Dan Mircea Ghiocel, Dan Ghiocel, Traian Mauna
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
The paper investigates the seismic SSI effects for rigid type structures. Structural response is computed by modal synthesis versus frequency response approach. The main aspects analysed are as follows: a) the seismic SSI effects on structural response; b) shortcomings in the current SSI computational procedure; c) seismic structure –soil-structure interaction (SSSI) effects on structural response of neighbouring heavy buildings. Two case studies are presented: a shearwell multistory building (SMB) on soft clay and a massive reactor building (RB). Seismic response quantities are accelerations, displacements, stresses, floor response spectra (FRS) and spectra amplification functions (SAF).
Experimental Studies On An Embedded Soil-Structure Interaction In A Case Of Hard Supporting Ground, Tomoyuki Lnukai, Masanori Izumi, Tamio Lmazawa, Eisuke Tanimoto
Experimental Studies On An Embedded Soil-Structure Interaction In A Case Of Hard Supporting Ground, Tomoyuki Lnukai, Masanori Izumi, Tamio Lmazawa, Eisuke Tanimoto
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In order to investigate the embedment effects exerted on the vibration behavior of reactor building, a series of tests is being carried out employing the use of a large-scale test model constructed on hard ground. This paper describes the embedment effects obtained from the forced vibration tests for the following items: 1) dynamic characteristics of soil-structure interaction system; 2) dynamic ground impedance; 3) soil pressure and so on.
Experimental Studies On The Dynamic Behavior Of Soft Clay Ground-Structures Supported By Friction Pile Foundations, N. Mori, T. Kondo
Experimental Studies On The Dynamic Behavior Of Soft Clay Ground-Structures Supported By Friction Pile Foundations, N. Mori, T. Kondo
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Recently, structures are often sited on a soft ground. So, a friction pile and a floating foundation are considered a possible and promising one. The object of this paper is to study the dynamic behavior of soft clay ground-structure supported by friction pile foundation on the basis of the shaking table test. Major results are as follows; 1) the residual settlement of structure resulting from decreasing the bearing capacity of the ground, wh1ch 1s caused by the accumulation of the excess pore water pressure, is larger than that of ground without structures. 2) The initial shear stress is a main …
Lumped-Parameter Model For Foundation On Layer, John P. Wolf, Antonio Paronesso
Lumped-Parameter Model For Foundation On Layer, John P. Wolf, Antonio Paronesso
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
A lumped-parameter model to represent a disk on the surface of a layer built-in at its base vibrating in horizontal, vertical, rocking or torsional motions is presented. Eight frequency-independent real coefficients determine the springs, dampers and the mass of the lumped-parameter model with two internal degrees of freedom. These coefficients are specified for various ratios of the radius of the disk to the depth of the layer and for various Poisson's ratios. To derive the mechanical properties of the lumped-parameter a systematic procedure of curve-fitting of the dynamic-stiffness coefficient up to at least twice the fundamental frequency of the layer …
Nonlinear Analysis Of Circular Plates On Nonlinear Foundation, Adel A. Mahmoud, Mohamed A. Nassar, Hazem M. Gheith
Nonlinear Analysis Of Circular Plates On Nonlinear Foundation, Adel A. Mahmoud, Mohamed A. Nassar, Hazem M. Gheith
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
Galerkin's procedure and the modified energy expression of Banerjee are used to obtain the central deflection of circular plates with linearly varying thicknesses, resting on a linear as well as a nonlinear elastic foundation. A new series formula for the deflection has been considered. The accuracy of the method has been tested for clamped plates with movable and immovable ends under uniform static patch loading. Graphical results are drawn for the central deflection for different end conditions, different plate thicknesses and different foundation properties. Comparison of the results are made with other known results and shows a good agreement in …
Nonlinear Seismic Analysis Of Building - Foundation Soil Systems, M. Sobaih, A. Gabr, A. H. Mahmoud, M. M. Bahloul
Nonlinear Seismic Analysis Of Building - Foundation Soil Systems, M. Sobaih, A. Gabr, A. H. Mahmoud, M. M. Bahloul
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
This paper deals with the problem of nonlinear seismic analysis of building - foundation soil systems. The building considered is modeled as a shear - type building supported on the surface of homogeneous isotropic elastic half-space. The governing nonlinear equations of motion for the structure - soil system are solved in the time domain using the step-by-step linear acceleration method of analysis with Wilson-e modification. Different nonlinear models to simulate the behaviour of reinforced concrete under cyclic loading are used. A parametric study has been performed on a single story shear-type building with different natural frequencies supported on the surface …
Numerical Simulation Of Shaking Table Test By Nonlinear Response Analysis Method, Mamoru Kanatani, Koichi Nishi, Jun-Ichi Touma, Masayuki Ohnami, Hiroyuki Namita
Numerical Simulation Of Shaking Table Test By Nonlinear Response Analysis Method, Mamoru Kanatani, Koichi Nishi, Jun-Ichi Touma, Masayuki Ohnami, Hiroyuki Namita
International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics
In this paper we described the results or numerical simulation or shaking table test on two dimensional soil-structure interation system to verify an application or newly developed nonlinear response analysis method. This code was a so-called U-W analysis method based on the deformation theory or saturated porous material proposed by Biot and constitutive relations to simulate the nonlinear characteristics or soils were induced by the elasto-plastic theory. Input material constants or soil were decided by referring the data or popular soil element test. Because the properties or soil were heavily dependent on confining pressure, then static and dynamic soil tests …