• Title/Summary/Keyword: Soil-Pile Interaction

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Building frame - pile foundation - soil interaction analysis: a parametric study

  • Chore, H.S.;Ingle, R.K.;Sawant, V.A.
    • Interaction and multiscale mechanics
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    • v.3 no.1
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    • pp.55-79
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    • 2010
  • The effect of soil-structure interaction on a single-storey, two-bay space frame resting on a pile group embedded in the cohesive soil (clay) with flexible cap is examined in this paper. For this purpose, a more rational approach is resorted to using the finite element analysis with realistic assumptions. Initially, a 3-D FEA is carried out independently for the frame on the premise of fixed column bases in which members of the superstructure are discretized using the 20-node isoparametric continuum elements. Later, a model is worked out separately for the pile foundation, by using the beam elements, plate elements and spring elements to model the pile, pile cap and soil, respectively. The stiffness obtained for the foundation is used in the interaction analysis of the frame to quantify the effect of soil-structure interaction on the response of the superstructure. In the parametric study using the substructure approach (uncoupled analysis), the effects of pile spacing, pile configuration, and pile diameter of the pile group on the response of superstructure are evaluated. The responses of the superstructure considered include the displacement at top of the frame and moments in the columns. The effect of soil-structure interaction is found to be quite significant for the type of foundation considered in the study. Fair agreement is observed between the results obtained herein using the simplified models for the pile foundation and those existing in the literature based on a complete three dimensional analysis of the building frame - pile foundation - soil system.

Seismic Analysis of Bridges Accounting for Soil-Pile-Structure Interaction (지반-말뚝-구조물 상호작용을 고려한 교량구조물의 지진해석)

  • Kim, Moon-Kyun;Lim, Yun-Mook;Cho, Kyung-Hwan;Kim, Ji-Sun
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2005.03a
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    • pp.405-412
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    • 2005
  • In this study, a numerical method for soil-pile-structure interaction problems in multi-layered half-plane is developed. The total soil-pile-structure interaction system is divided into two parts namely, nonlinear structure part and linear soil-pile interaction parts. In the structure field, the general finite element method is introduced to solve the dynamic equation of motion for the structure. In the soil-pile structure interaction part, physical model consisting of lumped parameter, which is frequency dependent coefficient and determined by rigorous analysis method is introduced. Using proposed analysis procedure, the nonlinear behavior of structure considering soil-structure interaction can be efficiently determined in time domain and the analysis cost is dramatically reduced.

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Analysis of Piled Piers Considering Riverbed Scouring (교각세굴을 고려한 말뚝기초의 해석)

  • Jeong, Sang-Seom;Suh, Jung-Ju;Won, Jin-Oh
    • Journal of the Korean Geotechnical Society
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    • v.18 no.3
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    • pp.43-50
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    • 2002
  • This paper describes a simplified numerical procedure for analyzing the response of bridge pier foundations due to riverbed scouring. A computationally efficient algorithm to analyze the behavior of a pile group is proposed by considering soil-pile, pile-cap, and pile-fluid interactions. The complex phenomenon of the pile-soil interaction is modeled by discrete nonlinear soil springs (p-y, t-z and q-z curves). The pile-cap interaction is considered by geometric configuration of the piles in a group and connectivity conditions between piles and the cap. The pile-fluid interaction is incorporated into the procedure by reducing the stiffness of the soil-pile reactions as a result of nonlinearity and degradation of the soil stiffness with river bridge scouring. Through the numerical study, it is shown that the maximum bending moment increases with increasing scour depth. Thus it is desirable to check the stability elf pile groups based on soil-pile and pile-cap interactions by considering scouring depth in the riverbed.

Upper and Lower Bound Solutions for Pile-Soil-Tunnel Interaction (한계해석법에 의한 파일-지반-터널 상호작용 해석)

  • Lee Yong-Joo;Shin Jong-Ho
    • 한국터널공학회:학술대회논문집
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    • 2005.04a
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    • pp.77-86
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    • 2005
  • In urban areas, new tunnel construction work is often taking place adjacent to existing piled foundations. In this case, careful assessment for the pile-soil-tunnel interaction is required. However, research on this topic has not been much reported, and currently only limited information is available. In this study, the complex pile-soil-tunnel interaction is investigated using the upper and lower bound methods based on kinematically possible failure mechanism and statically admissible stress field respectively. It is believed that the limit theorem is useful in understanding the complicated interaction behaviour mechanism and applicable to the pile-soil-tunnel interaction problem. The results are compared with numerical analysis. The material deformation patterns and strain data from the FE output are shown to compare well with the equivalent physical model tests. Admissible stress fields and the failure mechanisms are presented and used to develop upper and lower bound solutions to assess minimum support pressures within the tunnel.

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Interaction analysis of three storeyed building frame supported on pile foundation

  • Rasal, S.A.;Chore, H.S.;Sawant, V.A.
    • Coupled systems mechanics
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    • v.7 no.4
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    • pp.455-483
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    • 2018
  • The study deals with physical modeling of a typical three storeyed building frame supported by a pile group of four piles ($2{\times}2$) embedded in cohesive soil mass using three dimensional finite element analysis. For the purpose of modeling, the elements such as beams, slabs and columns, of the superstructure frame; and that of the pile foundation such as pile and pile cap are descretized using twenty noded isoparametric continuum elements. The interface between the pile and the soil is idealized using sixteen node isoparametric surface element. The soil elements are modeled using eight nodes, nine nodes and twelve node continuum elements. The present study considers the linear elastic behaviour of the elements of superstructure and substructure (i.e., foundation). The soil is assumed to behave non-linear. The parametric study is carried out for studying the effect of soil- structure interaction on response of the frame on the premise of sub-structure approach. The frame is analyzed initially without considering the effect of the foundation (non-interaction analysis) and then, the pile foundation is evaluated independently to obtain the equivalent stiffness; and these values are used in the interaction analysis. The spacing between the piles in a group is varied to evaluate its effect on the interactive behaviour of frame in the context of two embedment depth ratios. The response of the frame included the horizontal displacement at the level of each storey, shear force in beams, axial force in columns along with the bending moments in beams and columns. The effect of the soil- structure interaction is observed to be significant for the configuration of the pile groups and in the context of non-linear behaviour of soil.

Influence of Pile Cap On The Behaviors of End Bearing Pile Groups (말뚝캡이 선단지지 무리말뚝의 지지거동에 미치는 영향)

  • 최영석;이수형;정충기;김명모
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.245-252
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    • 2000
  • Model tests on free standing pile groups and piled footings with varying a pile spacing in two layered soils are carried out. The influence of pile cap on the behaviors of end bearing pile groups is analyzed by comparing the bearing behavior in piled footings with those in a single pile, a shallow footing(cap alone) and free standing pile groups. From the test results, it is found that the bearing characteristics of cap-soil-pile system are related with load levels and pile spacings. Before yield, the bearing resistance by cap is not fully mobilized, however, as the applied load increases, the bearing resistance of cap approaches to that of cap alone and settlement hardening occurs after yield due to the compaction caused by the contact pressure between cap and soil. By the cap-soil-pile interaction, shaft friction and point resistance of piles considerably increase with dependency of pile spacings. In two layered soil, the increasing effect of dilatancy in dense sandy soil adjacent to pile tips, increases the point resistance of pile.

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Numerical FEM assessment of soil-pile system in liquefiable soil under earthquake loading including soil-pile interaction

  • Ebadi-Jamkhaneh, Mehdi;Homaioon-Ebrahimi, Amir;Kontoni, Denise-Penelope N.;Shokri-Amiri, Maedeh
    • Geomechanics and Engineering
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    • v.27 no.5
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    • pp.465-479
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    • 2021
  • One of the important causes of building and infrastructure failure, such as bridges on pile foundations, is the placement of the piles in liquefiable soil that can become unstable under seismic loads. Therefore, the overarching aim of this study is to investigate the seismic behavior of a soil-pile system in liquefiable soil using three-dimensional numerical FEM analysis, including soil-pile interaction. Effective parameters on concrete pile response, involving the pile diameter, pile length, soil type, and base acceleration, were considered in the framework of finite element non-linear dynamic analysis. The constitutive model of soil was considered as elasto-plastic kinematic-isotropic hardening. First, the finite element model was verified by comparing the variations on the pile response with the measured data from the centrifuge tests, and there was a strong agreement between the numerical and experimental results. Totally 64 non-linear time-history analyses were conducted, and the responses were investigated in terms of the lateral displacement of the pile, the effect of the base acceleration in the pile behavior, the bending moment distribution in the pile body, and the pore pressure. The numerical analysis results demonstrated that the relationship between the pile lateral displacement and the maximum base acceleration is non-linear. Furthermore, increasing the pile diameter results in an increase in the passive pressure of the soil. Also, piles with small and big diameters are subjected to yielding under bending and shear states, respectively. It is concluded that an effective stress-based ground response analysis should be conducted when there is a liquefaction condition in order to determine the maximum bending moment and shear force generated within the pile.

Dynamic Interaction of Single and Group Piles in Sloping Ground (경사지반에 설치된 단일말뚝과 무리말뚝의 동적 상호작용)

  • Tran, Nghiem Xuan;Yoo, Byeong-Soo;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.36 no.1
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    • pp.5-15
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    • 2020
  • Dynamic behavior of pile foundation is significantly influenced by the dynamic interaction between soil and pile. Especially, in the sloping ground, the soil-pile interaction becomes very complex due to different resistance according to loading direction, soil residual displacement and so on. In this study, dynamic centrifuge tests were performed on the piles in the sloping ground. The model structures consisted of a single pile and 2×2 group pile. The soil-pile interaction has been investigated considering various conditions such as slope, single and group piles, and amplitude of input motions. The phase differences between soil and pile displacement and dynamic p-y curves were evaluated. The analysis results showed that the pile behavior was largely influenced by the kinematic forces between soil and pile. In addition, the dynamic p-y curve showed the complex hysteresis loop due to the effect of slope, residual displacement, and kinematic forces.

An Experimental Study of the Effect of Pile Cap on Behaviors of Group Piles (모형실험을 통한 사질토 지반에서의 무리말뚝 거동에 대한 상부기초 접촉 효과 연구)

  • 이수형;진봉근;정충기
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.259-266
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    • 1999
  • In case that pile cap is in direct contact with underlying soil, the bearing mechanism for pile groups, including direct bearing effect of cap and its induced influence on pile-soil-cap interaction, should be properly considered. In this paper, the effects of pile caps on behaviors of pile groups in sandy soils were investigated by model tests, which consist of tests on 3 by 3 pile groups with/without contact on subsoil, single pile with/without contact and cap as a shallow foundation. Also, the influences of pile spacing in group piles on contact effects were investigated. The test results showed that the load carrying capacity of pile cap was large enough not to be ignored. However, the interaction effects due to contact between cap and subsoils were not revealed obviously in working load range. And in the design of pile groups, the bearing effect of pile cap when contacted with subsoils, can be reflected by simply summing up load settlement behaviors of each cap and group piles without contact.

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A Forced Vibration Analysis of Soil-Pile Interaction System (지반-말뚝 상호작용계의 강제진동해석)

  • 김민규
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.04a
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    • pp.136-143
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    • 2001
  • In this study, a numerical analysis for soil-pile interaction systems in multi-layered half planes under a forced vibration is presented. The soil-pile interaction system is divided into two parts, so called near field and far field. The near field soil using finite elements and piles using beam elements are modeled. The far field soil media is implemented using boundary elements those can automatically satisfy the condition of wave radiation. These two fields are numerically coupled by imposing displacement compatibility condition at the interface between the near field and the far field. For the verification, the forced vibration test was simulated and the response under horizontal and vertical harmonic loads at the pile cap in the layered half plane was determined. The results are compared to the theoretical and experimental results of the literatures to verify the proposed soil-pile interaction analysis formulation.

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