A hydro-mechanical coupled algorithm for unsaturated soil in FLAC3D

摘要

In this study, a hydro-mechanical coupled algorithm is proposed to solve unsaturated soil problems in FLAC3D.The seepage model is extended using the in-built FISH language.The SWCC for unsaturated loess was best-fitted using MATLAB.The obtained parameters were written as a subroutine and invoked in each step in the seepage model to simulate seepage in unsaturated soil.Water infiltration at one-dimensional condition was modeled and compared using both the finite difference method and the finite element method, suggesting that the extension of the seepage model is appropriate.A non-linear elasto-plastic model was then defined to consider wetting induced variations in soil modulus and shear strength.Based on above improvement, a hydro-mechanical coupled analysis was performed to simulate sinkhole formation in unsaturated loess.The findings are meaningful in the investigation of the unsaturated soil theory and in the application of FLAC3D to simulate unsaturated soil problems.