Dynamic Responses of Pile Groups Embedded in a Layered Poroelastic Half-Space to Harmonic Axial Loads

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Bin Xu ◽  
Jian-Fei Lu ◽  
Jian-Hua Wang
Keyword(s):  
Half Space ◽  
Middle Layer ◽  
Pile Group ◽  
Dynamic Responses ◽  
Fredholm Integral Equations ◽  
Pile Groups ◽  
Axial Loads ◽  
Reflection Matrix ◽  
Patch Load ◽  
Layered Half Space

The dynamic responses of a pile group embedded in a layered poroelastic half-space subjected to axial harmonic loads is investigated in this study. Based on Biot’s theory, the frequency domain fundamental solution for a vertical circular patch load applied in the layered poroelastic half-space is derived via the transmission and reflection matrix (TRM) method. Utilizing Muki’s method, the second kind of Fredholm integral equations describing the dynamic interaction between the layered half-space and the pile group is constructed. The proposed methodology was validated by comparing the results of this paper with a known result. Numerical results show that in a two-layered half-space, for the closely populated pile group with a rigid cap, the upper softer layer thickness has different influences on the central pile and the corner piles, while for the sparse pile group, it has almost the same influence on all the piles. For a three-layer half-space, the presence of a stiffer middle layer in the layered half-space will enhance the impedance of the pile group significantly, while a softer middle layer will reduce the impedance of the pile group.

The Vibration of Pile Groups Embedded in a Layered Poroelastic Half Space Subjected to Harmonic Axial Loads by Using Integral Equations Method

2012 ◽  
Vol 204-208 ◽  
pp. 1170-1173
Author(s):  
Chun Bo Cheng ◽  
Man Qing Xu ◽  
Bin Xu
Keyword(s):  
Dynamic Response ◽  
Layer Thickness ◽  
Integral Equations ◽  
Half Space ◽  
Pile Group ◽  
Dynamic Interaction ◽  
Fredholm Integral Equations ◽  
Pile Groups ◽  
Axial Loads ◽  
Layered Half Space

The dynamic response of a pile group embedded in a layered poroelastic half space subjected to axial harmonic loads is investigated in this study. Based on Biot's theory and utilizing Muki's method, the second kind of Fredholm integral equations describing the dynamic interaction between the layered half space and the pile group is constructed. Numerical results show that in a two-layered half space, for the closely populated pile group with a rigid cap, the upper softer layer thickness has considerably different influence on the center pile and the corner piles, while for sparsely populated pile group, it has almost the same influence on all the piles.

Dynamic Interaction between the Pile Groups and Layered Poroelastic Half Space to Harmonic Axial Loads

2013 ◽  
Vol 405-408 ◽  
pp. 790-794
Author(s):  
Xue Jia Chen ◽  
Man Qing Xu
Keyword(s):  
Integral Equation ◽  
Half Space ◽  
Significant Influence ◽  
Pile Group ◽  
Dynamic Interaction ◽  
Fredholm Integral Equations ◽  
Pile Groups ◽  
Axial Loads ◽  
Good Agreement ◽  
Layered Half Space

By using Mukis method, the dynamic interaction between the pile group and layered poroelastic half space subjected to axial harmonic loads is investigated in this study. By using Mukis method, the second kind of Fredholm integral equations describing the dynamic interaction between the layered half space and the pile group is constructed. Numerical solution of the integral equation yields the axial force, the displacement of the pile as well as the response of the layered poroelastic half space. Results of this paper are compared with known results, which shows that our solutions is in a good agreement with the known result. The numerical results of this study also demonstrate that the soil inhomogeneity has a significant influence on the response of pile group.

Vibration Isolation Using Pile Rows in a Layered Poroelastic Half-Space Against the Vibration Due to Harmonic Loads

2010 ◽  
Author(s):  
Jian-Fei Lu ◽  
Bin Xu ◽  
Jian-Hua Wang
Keyword(s):  
Integral Equations ◽  
Half Space ◽  
Vibration Isolation ◽  
Dynamic Interaction ◽  
Isolation Effect ◽  
Fredholm Integral Equations ◽  
Vertical Load ◽  
Large Length ◽  
Patch Load ◽  
Transmission And Reflection

The isolation of the vibration due to a harmonic vertical load using pile rows embedded in a layered poroelastic half-space is investigated in this study. Based on Biot’s theory, the frequency domain fundamental solution for a vertical circular patch load applied in a layered poroelastic half-space is derived via the transmission and reflection matrices (TRM) method. Utilizing Muki and Sternberg’s method, the second kind of Fredholm integral equations describing the dynamic interaction between the pile rows and the layered poroelastic half-space subjected to a harmonic vertical load is constructed. The isolation effect of piles rows for the vibration due to the harmonic vertical load is investigated via numerical solution of the integral equations. Numerical results of this study show that a stiffer upper layer overlying a softer bottom half-space will worsen the vibration isolation effect of pile rows and vice versa. Also, pile rows with large length are preferable for a better vibration isolation effect.

Influence of Pile Geometry on Responses of End-Bearing Pile Groups Subjected to Vertical Dynamic Loads

2020 ◽  
Vol 20 (04) ◽  
pp. 2050050
Author(s):  
Lubao Luan ◽  
Xin Deng ◽  
Weiting Deng ◽  
Chenglong Wang ◽  
Xuanming Ding
Keyword(s):  
Superposition Principle ◽  
Pile Group ◽  
Dynamic Responses ◽  
Stress Distributions ◽  
Pile Groups ◽  
Pile Head ◽  
Interaction Factor ◽  
Pile Interaction ◽  
Refined Technique ◽  
End Bearing Pile

An analytical solution is presented for evaluating the dynamic responses of pile groups subjected to vertical harmonic loads. The solution allows us to consider the effects of pile geometry on the pile head impedance of the vertically loaded pile groups by the use of a new dynamic interaction factor. To this end, the stress distributions of the soil surrounding the vertically vibrating pile is first determined for calculating the pile–pile interaction factor, instead of the classical interaction factor based on two-pile displacements in past studies. Accordingly, the impedances of the pile group are derived using the proposed pile–pile interaction factor and the superposition principle. Some selected examples are presented to demonstrate the proposed refined technique for evaluating the dynamic characteristics of the pile group.

Cyclic axial behaviour of piles and pile groups in sand

2012 ◽  
Vol 49 (9) ◽  
pp. 1074-1087 ◽  
Author(s):  
Zheming Li ◽  
Malcolm D. Bolton ◽  
Stuart K. Haigh
Keyword(s):  
Axial Load ◽  
Pile Group ◽  
Offshore Structures ◽  
Pile Groups ◽  
Axial Loads ◽  
Bored Pile ◽  
Load Cycling ◽  
Permanent Settlement ◽  
Number Of Cycles ◽  
Piled Foundations

Piled foundations are often subjected to cyclic axial loads. This is particularly true for the piles of offshore structures, which are subjected to rocking motions caused by wind or wave actions, and for those of transport structures, which are subjected to traffic loads. As a result of these cyclic loads, excessive differential or absolute settlements may be induced during the piles’ service life. In the research presented here, centrifuge modelling of single piles and pile groups was conducted to investigate the influence of cyclic axial loads on the performance of piled foundations. The influence of installation method was investigated and it was found that the cyclic response of a pile whose jacked installation was modelled correctly is much stiffer than that of a bored pile. During displacement-controlled axial load cycling, the pile head stiffness reduces with an increasing number of cycles, but at a decreasing rate; during force-controlled axial load cycling, more permanent settlement is accumulated for a bored pile than for a jacked pile. The performance of individual piles in a pile group subjected to cyclic axial loads is similar to that of a single pile, without any evident group effect. Finally, a numerical analysis of axially loaded piles was validated by centrifuge test results. Cyclic stiffness of soil at the base of pre-jacked piles increases dramatically, while at base of jacked piles it remains almost constant.

Dynamic Response of Circular Plates Resting on Viscoelastic Half Space

1978 ◽  
Vol 45 (2) ◽  
pp. 379-384 ◽  
Author(s):  
Y. J. Lin
Keyword(s):  
Integral Equations ◽  
Half Space ◽  
Mixed Boundary ◽  
Dynamic Responses ◽  
Thin Plates ◽  
Fredholm Integral Equations ◽  
Circular Plates ◽  
Dual Integral Equations ◽  
Impedance Function ◽  
Vertical Excitation

Dynamic responses of circular thin plates resting on viscoelastic half space subject to harmonic vertical and rocking excitations are studied. The analysis is based on the assumption that the contact between the plate and the surface of the half space is frictionless. This dynamic mixed boundary-value problem leads to sets of dual integral equations which are reduced to Fredholm integral equations of the second kind and solved by numerical procedures. The numerical results show that the rocking impedance function is independent of the plate flexibility, but the vertical excitation is not.

scholarly journals A Semi-Analytical Model for the Simulation of the Isolation of the Vibration Due to a Harmonic Load Using Pile Rows Embedded in a Saturated Half-Space

2010 ◽  
Vol 4 (1) ◽  
pp. 38-56 ◽  
Author(s):  
Bin Xu ◽  
Jian-Fei Lu ◽  
Jian-Hua Wang
Keyword(s):  
Integral Equations ◽  
Half Space ◽  
Analytical Model ◽  
Vibration Isolation ◽  
Fredholm Integral Equations ◽  
Harmonic Load ◽  
Dynamical Interaction ◽  
Vibration Effect ◽  
Patch Load ◽  
Isolation Vibration

The isolation of the vibration due to a harmonic vertical load using pile rows embedded in a saturated poroelastic half-space is investigated in this study. Using the fundamental solution for a circular patch load and Muki’s method, the second kind of Fredholm integral equations describing the dynamical interaction between the pile rows and the saturated poroelastic half-space are obtained. Numerical solution of the integral equations yields the dynamic response of the pile-half-space system. The vibration isolation effect of the pile rows is investigated via the proposed semi-analytical model. Numerical results indicate that stiffer piles have better isolation vibration effect than flexible piles. Moreover, the pile length and the spacing between neighboring piles in one pile row have significant influence on the isolation vibration effect of pile rows, while the influence of the spacing between neighboring pile rows is relatively smaller.

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