How to Use COMSOL Multiphysics for Coupled Dual-permeability Hydrological and Slope Stability Modeling

Preferential flow paths, such as cracks, macropores, fissures, pipes etc. are common features of highly heterogeneous slopes. During intense rainstorms, preferential flow has a significant influence on subsurface flow and slope stability. Dual-permeability models are widely used to simulate preferential flow, but have not been incorporated into hydro-mechanical models. In this study, the COMSOL Multiphysics software was used to couple a dual-permeability model with a soil mechanics model for landslide stability evaluation on a hillslope scale with examples of up to 100m spatial scale. Detailed information is provided on how to incorporate current hydrological and soil mechanics theories into COMSOL. The model is benchmarked against two existing solutions and is applied to evaluate the effect of preferential flow on slope stability as an example.