Numerical Simulation Of The Triaxial Test For Soil Stress-strain Behavior

The study of the strength and characteristics and deformation behavior of soil is still a important part of soil mechanics.The studies of constitutive model of soil were reported in many articles,which regarded the soil in triaxial test as a element.But soil is a kind of structure body,it shows different kinds of deformation behavior in different stages.The traditional constitutive model of soil could not describe this kind of different.In this paper,the author simulated the triaxial test of soil using ABAQUS,find out that one point of the soil specimen only has two states: damaged and undamaged,by a simple stress-strain relationship.The soil of triaxial test is a structure body,shouldn't be regarded as a element body.The undamaged part's stress-strain relationship should be non-linear relationship;the damaged part features sliding friction of soil particles.The stress-strain relationship of soil specimen in triaxial test should be divided into three stages: undamaged stage,damaging stage,damaged stage.Through the method of numeric simulation,it is proved the soil specimen in triaxial test shows different deformation behavior by stages.In the undamaged stage,every point in soil specimen have a similar stress-strain relationship and deformation.In damaging stage,deformation behavior shows difference in different part of soil specimen.In damaged stage,the strain of soil specimen comes from the bilateral displacement of shear band.There is no need to use the traditional constitutive model to describe the stress-strain relationship.This paper verified the extension criterion of shear band based on X-FEM accord with the result of triaxial test.In the extension of shear band,X-FEM doesn't need afresh meshing.The inclination and shape of shear band got from this method have strong according with the triaxial test.