Research On The Triple-shear Unified Structured Constitutive Model For Homogeneous Saturated Clay And The Secondary Development For ABAQUS

The most widely used constitutive models for soils are based on the remoldedsoil tests. Such constitutive models without considering soil structures，which cannotdescribe the structural influences on mechanical properties of soils. Generally speak,the nature soils have their certain structures, Therefore，it is significant to researchthe structured stress-strain relationship and establish structured constitutive modelsfor soils.Study on the homogeneous saturated clays. According to the stresstransformation, through differentI1and to control soil failure ratio. Propose thetriple-shear unified structured constitutive model for clay by using triple-shearunified theory as the failure criterion and combined with structured cam-clay model.The model can better reflect the structural of clay.The numerical integration method have been simulated the triaxial,K0compression and the true triaxial compression tests under the drainage andundrained stress path. The relationship between stress and strain and the porewaterpressure variation regulation have been discussed. The code to solve equation hasbeen compiled on Microsoft Visual Studio2008(Intel Visual Fortran CompilerProfessional11.1). Studied the influence of the b and B, verified the effectiveness ofthe proposed model by comparing with the existing literature.The three parameters ofI1,J2andJ3are used to express the triple-shear unifiedstructured constitutive model for clay and the elastic-plastic constitutive matrix ofthe finite element method is obtained. This elastic-plastic constitutive model of thetheory is derived based on the associated flow rule.The finite element subroutine of the triple-shear unified structured constitutivemodel is compiled by Fortran on the second development platform (UMAT) ofABAQUS. It can provide reference about the second development of ABAQUS forgeotechnical researcher.