沉桩挤土效应对桩周土体径向位移数值分析

Numerical analysis of radial displacement of soil around pile by compacting effect of pile driving

沉桩过程中桩周土体会发生挤土效应,产生较大的应力和位移,引起桩周土体侧向移动、地表隆起,甚至影响相邻建筑物的基础稳定及安全,造成不利的后果[1]。文章利用有限元分析软件ABAQUS,建立合理的二维轴对称模型,采用修正剑桥屈服准则,有效解决理论不能考虑的大变形问题、地基初始应力场、接触问题,结合离心试验[2]数据,验证模型的准确性,更加真实地模拟沉桩挤土效应。对不同深度及不同土质参数情况下挤土效应产生的径向位移进行分析,研究沉桩过程中桩周土体径向位移的变化规律。

Under the effect of the pressure, the pile was pressed into the soil which produce groat compaction effect. The stress and displacement of the soil became increased which cause lateral movement of soil and uplift of gound surface, even affected the stability and safety of adjacent building＇s understructure, it will have adverse consequences. A two-dimensional axisymmetric finite element model was built which accorded to the software of ABAQUS. Based on the Critical state plasticity model, the following problems were solved including finite deformation problem, constant problem, elastoplasic constitutive law, load applied problem, foundation＇s initial geostatic pressure field. Combining with the centrifuge test data, the accuracy of the model was verified, and the compaction effect of pile driving was simulated more authentic. The radial displacement of soil effect under different soil depth and different soil parameters was analyzed, and the variation law of radial displacement of soil around pile during the process of pile driving was studied.