考虑固结效应的筏板基础与地基共同作用弹塑性数值分析

Numerical analysis of raft-foundation interaction system considering consolidation effect of ground and elasto-plastic behaviour of soils

地基固结作用呈现明显的非线性特征,对建筑物沉降变形的影响不容忽视,为此,基于B iot固结理论,对于地基土采用M ohr-Cou lom b理想弹塑性模型,对筏板基础与地基共同作用问题进行了非线性固结弹塑性有限元数值分析.计算结果表明地基中孔隙水压力的消散及其相关的M ande l-C ryer效应与筏板基础的内力变形特性的时间效应具有密切的联系,地基固结作用对筏板-地基共同作用体系的内力变形特性具有显著的影响.因此,在结构-地基相互作用分析与工程设计中考虑地基固结效应是十分必要的.

Effects of consolidation of soft soil ground on performance of rafts and foundation interaction system can not be overlooked. In fact, the interaction system of rafts and foundation soils will display a certain nonlinear characteristics. Elasto-plastic FEM （finite element method） analyses are conducted by numerically solving the fully coupled consolidation equations in which perfect elasto-plastic constitutive model based on Mohr-Coulomb＇s criterion of failure is incorporated in the FEM formulation of Biot＇s consolidation equations. It is shown that the consolidation characteristics of soils remarkably affect the time-dependent performance of interaction of rafts and soils and the dissipation of excess pore pressures is intimately associated with Mandel-Cryer effects especially under poor drainage condition. It is demonstrated that the consolidation analyses can give a more rational evaluation of overall performance of interaction of rafts and soils.