| Because pile foundation has many advantages,it is widely used in civil engineering,Marine,port terminals,oil and gas transportation engineering.The survey of previous earthquake damage: Soil liquefaction leads to bearing capacity failure of pile foundation,which results in that structural damage or collapse cases often happen.Therefore,about the research of pile foundation in liquefiable site,especially the research of lateral dynamic response characteristics of pile group,has been a concern in the field of geotechnical earthquake engineering at home and abroad.Based on the complexity of dynamic interaction process for soil-pile group-pile caps,research methods are also more at present.In this article,the lateral dynamic response characteristics of pile groups through the shaking table test which use the model of soil-pile group-caps structure have been analysed.On this basis,a three dimensional model of liquefied soil has been established in order to carry out the numerical simulation of pile group dynamic response with the finite element software OpenSees.The main research work is as follows:(1)In the design of the shaking table test for pile group,the FBG sensing system to measure soil displacement and strain for group pile firstly has been used.In terms of test condition,the shaking table test which is inputed respectively in dry and saturated sand by different peak acceleration sine wave and seismic wave in the basement for pile-group lateral dynamic response characteristics has been carried out.(2)The geometrical model of pile soil interaction with the pre-processing software GID has been meshed through learning the basic usage of Tcl scripting language and OpenSees software user manual systematically.What’s more,based on the model of shaking table test,the 3D finite element model of 3*3 pile group-cap structure has been built through writing a new code of Tcl.(3)Based on the various operating conditions of test,a established three-dimensional finite element numerical analysis model has been run and debugged repeatedly.Eventually,numerical simulation results are concluded by debugging some parameters in OpenSees software.(4)Compared with the results of numerical simulation and test,mainly including the acceleration,displacement and pore water pressure time history for mesa of pile caps.The comparison results show that the change rule of simulation results almost is same to testanalysis,It is proved that this can well realize the simulation of dynamic response problem for group pile in saturated sandy soil with OpenSees software,and the calculate and convergence speed than other finite element software;At the same time,it verifies the reliability of three-dimensional numerical analysis model established in this paper and lays a foundation for big size pile model test and numerical analysis of actual project. |
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