Centrifuge Shaking Table Test And Numerical Simulation For Dynamic Response Of Pile Group In Liquefaction Site

Pile foundation is the main application form of liquefaction site building foundation.The dynamic response law of pile group foundation in liquefaction site has always been the focus of seismic research.This paper studies domestic and foreign literature,combined with the domestic research progress on the lateral dynamic response characteristics of pile group foundation in liquefaction site and the interaction between pile and soil,to avoid the problem that there is a big gap between the current research model and the actual engineering pile group stress process,research on lateral dynamic response of pile group foundation and pilesoil interaction in liquefaction site under prototype stress-strain relationship was carried out.Main contents include: Under the input of sinusoidal wave with different peak acceleration and el-centro seismic wave,the vibration table test of 2×2 group pile foundation centrifuge in saturated sand foundation was carried out.Through the processing of test data,the transverse dynamic response characteristics of group pile cap and foundation soil were analyzed.At the same time,a grid-adaptive rotor-stator coupling numerical model for the interaction between pile group foundation and foundation soil in the liquefaction site was established,and the program of the large-scale finite element ABAQUS computing platform was used to develop the secondary port,and the liquefaction large deformation constitutive program was introduced to analyze the dynamic response of pile group during the liquefaction disaster in the foundation.The main achievements of this paper include:(1)The aluminum 2×2 tube pile-cap foundation type is adopted,and two transverse excitation input modes,sine wave and el-centro seismic wave,are selected for the liquefaction field of saturated sandy soil.The centrifuge shaking table test for the interaction between pile group foundation and foundation soil in the liquefaction field under different working conditions with peak acceleration and frequency variation,is successfully completed.(2)A detailed analysis of centrifuge shaking table test data,the research group of pile in liquefied ground-the interaction mechanism of the foundation soil,discusses different peak acceleration under the transverse vibration of the pile caps,different depth of foundation soil in super static pore water pressure and acceleration in the dynamic response rule of foundation liquefaction process,analysis of softening of foundation soil and pile foundation under dynamic action to the significant effect in the process of liquefaction,and to establish a consideration of dynamic and static coupling sand liquefaction large deformation finite element numerical model provides the necessary data model.(3)Based on ABAQUS finite element computing platform,large based on centrifuge shaking table test,through the secondary development of ABAQUS port is introduced into the hardening parameter increment and hardening rules of sand liquefaction modified large deformation constitutive program,established the movement coupling of saturated sand ground dynamic response of pile-soil interaction two-dimensional numerical model,to solve the problem of saturated sand liquefaction mesh distortion after adopting the grid adaptive technology.(4)Analysis,the result calculated by numerical model established in this paper,further study of different horizontal peak ground acceleration excitation super static pore water pressure of saturated sandy soil foundation rising regularity,illuminates the saturated sand liquefaction under lateral load in the process of the super static pore pressure than the development of the foundation soil and the correlation between the acceleration change of soil.