非线性地基上圆形刚性基础的分析

ANALYSES OF CIRCULAR RIGID FOOTINGS ON NONLINEAR SUBSOIL

为了评价土的各种非线性本构模型在分析基础与地基相互作用问题中的适用性，作者用有限元法编制了计算机程序，并用该程序分别对受竖向中心荷载作用的三个圆形刚性基础进行了计算和分析．地基模型分别采用不同的非线性弹性和弹塑性模型。计算结果表明，在浅基础分析中采用上述模型能较好地反映土的非线性或非弹性性质。在饱和不排水地基中采用ＤｕｎＱｍ—Ｃｈａｎｇ模型的计算结果较接近实测值，而Ｍｏｈｒ－Ｃｏｕｌｏｍｂ模型和Ｄｒｕｃｋｅｒ—Ｐｒａｇｅｒ模型的计算值则偏小。剑桥模型和修正剑桥模型能在一定程度上反映饱和排水粘土地基的变形性状。

For the purpose of evaluating the suitabilities of various nonlinear soilmodels to the analysis of interaction between footings and supporting soil mass, acomputer program using FEM has been developed by the authors. In this paper,onlythe calculated results of three circular rigid footings subjected to a central vertical loadrespectively, are presented for illustration. They are obtained by using above mentionedprogram and the subsoil is represented by different nonlinear--elastic/elastoplastic soilmodels respectively. The calculated results show that the above models are able to reflect better the nonlinear or nonelastic property of soil in shallow foundation analysis.For the saturated subsoil under undrained condition, the calculated results obtained byDuncan-Chang model fit well to those of field observation,but those obtained byMohr-Coulomb model and Drucker-Prager model are smaller.To a certain extent,Cam-clay model and revised Cam-clay model are able to reflect the deformationbehaviour of saturated clay under drained condition.