不同应力路径下粘土的本构关系验证

Verification of Clay Constitutive Model under Different Stress Paths

本文通过对小浪底土坝心墙粘土等应力比和变应力比的固结排水剪切试验,研究了不同应力路径下粘土的应力应变特性。结果表明,应力路径对土的应力应变关系有显著的影响,而对强度指标则影响很小;在一定的等应力比范围内,土的应力应变关系具有较好的归一性。对邓肯-张模型、修正剑桥模型和双屈服面弹塑性模型进行了验证,这些模型对应力路径的适应性各不相同。根据几种基本试验,利用插值方法推求了等应力比路径下土的应力应变关系曲线,取得了较为满意的结果。

A number of consolidated drainage shear tests on the core clay of Xiaolangdi Dam with a constant stress ratio and varied stress ratios are carried out.The stress-strain properties of clay under different stress paths are analyzed,and the result indicates that the stress path has obvious influence on the stress-strain of soil,but almost no influence on the strength parameter ,and stress-strain rela- tions of soil in a certain range of constant stress ratio can be generalized.The Duncan-Chang model, the revised Cambridge model and the elasto-plastic model for soils with two yield surfaces are verified, and it is shown that the adaptabilities of these models to the stress path are different.According to a few basic tests and by use of interpolation,the stress-strain relationship ccurves under the stress path with different constant stress ratios axe ascertained successfully.