非饱和黏性土的三剪次加载面模型研究  

Three-shear sub-loading surface model of unsaturated clay

作　　者：胡小荣 蔡晓锋 陈昊 路祥 HU Xiaorong;CAI Xiaofeng;CHEN Hao;LU Xiang(School of Infrastructure Engineering,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学工程建设学院,南昌330031

出　　处：《振动与冲击》2023年第7期194-206,共13页Journal of Vibration and Shock

基　　金：国家自然科学基金资助项目(10862004,11362016)。

摘　　要：基于非饱和土三剪强度准则和次加载面模型,构建了适用正常固结非饱和黏性土的Bishop和Fredlund应力变量法三剪次加载面模型,将2个模型计算结果与非饱和黏土的单调静三轴试验及循环动三轴试验结果做了对比,结果表明,Fredlund应力变量法本构模型要更接近试验结果。在静三轴试验的土体变形后期,Fredlund和Bishop应力变量法的模型计算结果与试验数据的应力偏差分别为2%和10%;在动三轴试验的土体振动后期,Fredlund和Bishop应力变量法与试验结果的应变偏差分别为4.2%和7.5%。另外,对所提模型的真三轴分析结果可知,静真三轴试验的中间主应力影响系数和基质吸力的增大均会使得土体的抗剪强度增加,随着基质吸力增大,不同模拟结果依次的应力偏差均为11%左右;随着中间主应力影响系数增大,不同模拟结果之间的应力偏差大致为4%。动真三轴试验的最小主应力或中间主应力越大,非饱和黏性土的棘轮效应和抗剪强度也越大,不同中间主应力模拟结果之间的应变偏差为3.3%,不同最小主应力模拟结果之间的应变偏差为8.5%。Here,based on unsaturated soil three-shear strength criterion and sub-loading surface model,Bishop stress variable method three-shear sub-loading surface model and Fredlund one applicable to normally consolidated unsaturated clay were constructed,respectively.The calculation results of the two models were compared with the results of monotonic static triaxial tests and cyclic dynamic triaxial tests of unsaturated clay.The results showed that Fredlund stress variable method constitutive model is closer to test results;in later stage of soil body deformation of static triaxial tests,stress deviations between model calculation results of Fredlund and Bishop stress variable methods and test data are 2%and 10%,respectively;in later stage of soil body vibration of dynamic triaxial tests,strain deviations between Fredlund and Bishop stress variable methods and test results are 4.2%and 7.5%,respectively;according to true triaxial analysis results of the proposed models,increase in intermediate principal stress influence coefficient and matric suction in static true triaxial tests can increase anti-shear strength of soil body;with increase in matric suction,stress deviations of different simulation results in turn all are about 11%;with increase in influence coefficient of intermediate principal stress,stress deviations among different simulation results are about 4%;the larger the minimum principal stress or intermediate principal stress of dynamic true triaxial tests,the bigger the ratcheting effect and anti-shear strength of unsaturated clay;strain deviations among different intermediate principal stress simulation results are 3・3%,and strain deviations among different minimum principal stress simulation results are 8.5%.

关 键 词：非饱和黏性土 三剪次加载面模型 Bishop应力变量法 Fredlund应力变量法 三轴试验 

分 类 号：TU432[建筑科学—岩土工程]