正常固结原状饱和黏性土的三剪统一结构性本构模型

摘要

基于扰动状态概念,采用非线性弹性本构模型来表征原状黏性土的相对完整状态,将三剪统一强度准则与修正剑桥模型相结合来表征原状黏性土的完全调整状态,提出了饱和原状黏性土结构性本构模型.通过坐标平移法确定的破坏应力比使所提出模型能够反映全应力状态变化下的强度区间效应和拉压差,也能够描述黏聚力在土体受力过程中的作用.为验证所提出模型的正确性,以江西原状饱和红黏土为试验土样,做了排水和不排水条件下的常规三轴压缩试验,将模型计算结果与试验结果进行对比,结果表明,所提模型能够较好地反映江西原状饱和红黏土的力学和变形特性.%The triple-shear unified structured constitutive model is proposed for the undisturbed saturated clay in normal consolidation based on the disturbed state concept,in which the relative intact state is characterized by the non-linear elastic model,and the fully adjusted state is characterized by the elasto-plastic model built with the combination of the triple-shear unified failure criterion and the modified Cam-clay model in the critical state soil mechanics.The coordinate translation is presented to describe the influences of the cohesion on the soil mechanical properties better.The proposed model can overcome the shortcomings of the modified cam-clay model with the definite failure stress ratio without considering the soil cohesion,which can't reflect the practical differences of strength properties under different stress states and soil cohesion.The advantage is that the new model could show the practical effects under the different stress states acting on the saturated structured clay with different cohesion better.It is shown that it can describe the effects of intermediate principal stress,rang changes of stress and difference between tension and compression.In order to verify the model proposed here,comparisons between the numerical simulations and experimental results under conventional tri-axial compression to the Jiangxi undisturbed lateritic clay was made,which results show that the proposed model could reflect the mechanical and deformation characteristics of the Jiangxi undisturbed lateritic clay well.