Numerical Implementation of a Hydro-Mechanical Coupling Constitutive Model for Unsaturated Soil Considering the Effect of Micro-Pore Structure

An unsaturated soil constitutive model considering the influence of microscopic pore structure can more accurately describe hydraulic–mechanical behavior soil, but its numerical implementation is complicated. Based on fully implicit Euler backward integration algorithm, ABAQUS software used to develop established hydro-mechanical coupling for micro-pore structure, and a new User-defined Material Mechanical Behavior (UMAT) subroutine realize application proposed model. The developed program simulate drying/wetting cycle process standard triaxial specimen. simulation results are basically consistent with those calculated by Fortran program, which verifies rationality program.