管—土相互作用的有限元分析

Finite Element Analysis on Pipe-Poil Interaction

采用有限元方法，分析了管—土相互作用。在假定此问题为轴向对称的前提下，选用了二结点锥环元，并导出了这种单元的几何非线性刚度矩阵，同时还考虑了管壁向内凹陷时局部管与土脱离的现象。在求解非线性方程时，为了克服极值点处Ｊａｃｏｂｉ矩阵的奇异性，采用了弧长法。推导出了管变形随荷载变化规律和管屈曲的上、下临界荷载。

This paper analyzes the pipe-soil interaction by means of finite element method.On the premise that the problem be of axial symmetrical,the two-node conical ring element is used,then the geometrically nonlinear stiffness matrix of the element is formulated,while taking the separation of the pipe from the soil due to depression of the pipe into consideration.In solving nonlinear equations,arc length method is adopted so as to avoid Jacobi matrix’s singularity at extreme value points.Finally,the variation of the pipe defomation with loads,and the upper and lower limits of the critical load are computed.