A two-dimensional thermal-hydro-mechanical bond contact model for methane hydrate bearing soils

The strength and deformation of methane hydrate bearing soils are influenced by their inter-particle cemented hydrate, the extent of which depends on the surrounding temperature, pore-water pressure and mechanical environment. It is aimed to establish a thermal-hydro-mechanical bond contact model for methane hydrate bearing soils. Firstly, contact force-displacement laws and bond failure criteria are presented according to two types of bond modes that methane hydrate may present. Secondly, the strength and stiffness of inter-particle cemented hydrate are studied with respect to the parameter L which identifies the minimum distance from a point to the phase equilibrium line in the coordinate system with ordinate being dimensionless pore-water pressure and abscissa being dimensionless temperature. Finally, the size of cemented hydrate is calculated corresponding to the methane hydrate saturation. The proposed bond contact model can be easily implemented into the distinct element method (DEM), providing an efficient tool for investigating the macro- and micro-mechanical behaviors of methane hydrate bearing soils.