土剪胀性的应力路径相关规律及其模拟

INFLUENCE OF THE STRESS PATH ON DILATANCY OF SOILS AND ITS MODELING

建立能够反映土的变形和强度特性应力路径依存性的本构模型,首先需要解决土剪胀规律的应力路径依存性问题.对黏土和砂土剪胀性的应力路径依存性做了系统的分析和比较,模型预测与试验结果的比较表明:剑桥模型和统一硬化模型在描述土的这一特性方面都有一定缺陷;采用部分塑性体应变与塑性剪应变耦合的思路建立的渐近状态模型能够较好地反映土剪胀性的应力路径依存性.

One of the most important characteristics of soil is its dilatancy in which plastic volumetric strain occurs during shearing.The influence of stress path on the dilatancy of soils is systematically analyzed in this paper with the asymptote state model proposed by authors et al（Luo et al,2009）,in which the part coupling effect between the plastic volumetric strain and plastic shear strain is assumed firstly.The comparisons are carried out between the test results of the dilatancy and the model predictions of the original Cam-Clay model, the modified Cam-Clay model,the unified hardening model（Yao et al,2008） and our proposed model.The comparisons results demonstrate that the asymptote state model can describe the effect of the stress path on the dilatancy of soils in a better way in the stress-strain and strength behaviors of soils.