不同主应力方向下各向异性砂土力学响应的本构模型模拟  

tsinghua.edu.cn。Constitutive model simulation for mechanical response of anisotropic sand under different principal stress directions

作　　者：余嘉轲 王睿 张建民[1] YU Jiake;WANG Rui;ZHANG Jianmin(Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学水利水电工程系,北京100084

出　　处：《岩土工程学报》2024年第3期670-677,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52022046);北京市自然科学基金项目(J210003)。

摘　　要：地下水位上升可能引发饱和松散土体边坡有效球应力降低从而诱发稳定性问题。等剪应力排水路径能够模拟饱和砂土边坡内土体单元在潜水面上升时的应力条件,但目前各向异性对于这种应力路径下土的响应的影响仍不明确。采用一个各向异性砂土弹塑性本构模型对不同主应力方向下的定轴等剪应力排水试验进行模拟,分析各向异性影响规律。该本构模型考虑了组构各向异性的演化及其对塑性模量和剪胀的影响,能够反映不同主应力方向对土体力学响应的影响。模拟结果表明,该模型能够较好地模拟不同主应力方向下饱和砂土在定轴不排水剪切和定轴等剪应力不排水条件下的响应。对于定轴等剪应力不排水应力路径,非稳定态时的平均有效应力随孔隙比和加载角度的增加而增加,不同初始组构强度对于等剪应力排水试验的结果有显著的影响。Rising ground water level reduces the mean effective stress within ground soil and may cause stability problems for the slopes in saturated loose sand.The constant shear drained(CSD)stress path represents the stress conditions with rising phreatic surface,yet the influences of anisotropy on soil response under such stress path are still unclear.In this study,the anisotropic CycLiq model is used to simulate the CSD stress tests under different principal stress directions.Based on the original CycLiq model,the model considers the evolution of fabric anisotropy and its influences on plastic modulus and dilatancy,and can simulate the influences of different principal stress directions.The simulated results achieve good agreement with the test results for undrained shear and CSD loading under different intermediate stress coefficients and principal stress directions.For the CSD tests,the mean effective stress in instability state is observed to increase with the increasing void ratio and loading angle.The initial fabric norm is shown to have significant influences on the stress ratio at the instability state in the CSD tests.

关 键 词：各向异性砂土 数值模拟 本构模型 主应力方向 等剪应力排水路径 

分 类 号：TU435[建筑科学—岩土工程]