An elasto-plastic constitutive model incorporating strain softening and dilatancy for interface thin-layer element and its verification  

作　　者：彭凯 朱俊高 冯树荣 王荣 刘汉龙 

机构地区：[1]Hydrochina Zhongnan Engineering Corporation [2]Key Laboratory of Geo-mechanics and Embankment Engineering of Ministry of Education(Hohai University) [3]Geotechnical Research Institute,Hohai University

出　　处：《Journal of Central South University》2012年第7期1988-1998,共11页中南大学学报（英文版）

基　　金：Project(20110094110002) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China;Project(200801014) supported by the Ministry of Water Resources of China;Project(50825901) supported by the National Natural Science Foundation of China

摘　　要：The mechanical behaviors of the interface between coarse-grained soil and concrete were investigated by simple shear tests under condition of mixed soil slurry (bentonite mixed with cement grout).For comparison,the interfaces both without slurry and with bentonite slurry were analyzed.The experimental results show that different slurries exert much influence on the strength and deformation of soil/structure interface.Under mixed soil slurry,strain softening and shear dilatation are observed,while shear dilatation appears under the small normal stress of the interface without slurry,and shear contraction is significant under the condition of the bentonite slurry.The thickness of the interface was determined by analyzing the disturbed height of the sample with both simple shear test and particle flow code (PFC).An elasto-plastic constitutive model incorporating strain softening and dilatancy for thin layer element of interface was formulated in the framework of generalized potential theory.The relation curves of shear stress and shear strain,as well as the relation curves of normal strain and shear strain,were fitted by a piecewise function composed by hyperbolic functions and resembling normal functions.The entire model parameters can be identified by tests.The new model is verified by comparing the measured data of indoor cut-off wall model tests with the predictions from finite element method (FEM).The FEM results indicate that the stress of wall calculated by using Goodman element is too large,and the maximum deviation between the test data and prediction is about 45%.While the prediction from the proposed model is close to the measured data,and the error is generally less than 10%.The mechanical behaviors of the interface between coarse-grained soil and concrete were investigated by simple shear tests under condition of mixed soil slurry （bentonite mixed with cement grout）. For comparison, the interfaces both without slurry and with bentonite slurry were analyzed. The experimental results show that different slurries exert much influence on the strength and deformation of soil/structure interface. Under mixed soil slurry, strain softening and shear dilatation are observed, while shear dilatation appears under the small normal stress of the interface without slurry, and shear contraction is significant under the condition of the bentonite slurry. The thickness of the interface was determined by analyzing the disturbed height of the sample with both simple shear test and particle flow code （PFC）. An elasto-plastic constitutive model incorporating strain softening and dilatancy for thin layer element of interface was formulated in the framework of generalized potential theory. The relation curves of shear stress and shear strain, as well as the relation curves of normal strain and shear strain, were fitted by a piecewise function composed by hyperbolic functions and resembling normal functions. The entire model parameters can be identified by tests. The new model is verified by comparing the measured data of indoor cut-off wall model tests with the predictions from finite element method （FEM）. The FEM results indicate that the stress of wall calculated by using Goodman element is too large, and the maximum deviation between the test data and prediction is about 45%. While the prediction from the proposed model is close to the measured data, and the error is generally less than 10%.

关 键 词：simple shear test mixed soil slurry DILATANCY particle flow code generalized potential theory constitutive model FEM 

分 类 号：TV431[水利工程—水工结构工程]