单桩复合地基固结性状有限元分析

FEM analysis of consolidation behavior of composite ground with single pile

在编制并验证Biot固结有限元(FEM)程序的基础上,对单桩复合地基固结进行了有限元分析,并比较了强排水桩复合地基和弱排水桩复合地基的固结性状.对于强排水桩复合地基:渗流以径向为主;是否考虑应力集中对平均固结度影响甚微,但对地基浅层孔压分布产生较大影响.对于弱排水桩复合地基:渗流以竖向为主;无论考虑应力集中与否,孔压分布和天然地基相比在深度方向梯度更大,由此形成的应力差更利于孔压向透水面的消散,从而加速了地基的固结.

The programming and validating FEM code of Biot's consolidation theory were used for FEM analysis of the consolidation of composite ground with single pile, and the consolidation behavior of composite ground with strong drainage pile was compared with the one with weak drainage pile. For composite ground with strong drainage pile, the main flow is in radial direction; and while the average consolidation degree is negligibly affected by stress concentration, the pore water pressure in shallow soil is greatly affected. For composite ground with weak drainage pile, the main flow is in vertical direction, and whether the stress concentration effect is or not taken into account, the gradient of pore water pressure along depth is greater than that in natural ground. This benefits dissipation of pore water pressure and thus accelerates the consolidation rate.