近海风机单桩基础桩周土应力特征分析

摘要

桩周土体的力学响应规律对近海风机桩基础的变形和稳定性有重要影响。采用有限元方法对一个概化的近海风机单桩基础进行数值模拟，着重分析动荷载作用下桩基础和桩周土的变形规律、桩周土应力作用特征及应力主轴的旋转模式。发现桩周土体各方向的应力分量随循环荷载的作用呈现出周期性的往返变化，第一周期的应力路径与继后周期的应力路径明显不同，浅层桩周土存在显著的应力主轴往复旋转，旋转幅度可达60°。%The mechanical behavior of soil plays a significant role in the deformation and stability of the pile foundations of offshore wind turbines.The soil’s stress path around the pile foundation is complex under the wind and wave loadings.This paper conducts a numerical simulation for a simplified pile foundation using the finite element method (FEM),and studies the deformation, stress path,and rotation mode of the principal stress axes under cyclic loadings.We found that the soil’s stress components around a pile foundation show periodical variation with an increasing number of cycles.The stress path in the first cycle is significantly different from that in subse-quent cycles.We observed a marked repetitive rotation of the principal stress axes in the shallow region of the soil foundation and the rotation amplitude that it can reach.