DEM analysis on formation of shear band of methane hydrate bearing soil under different temperatures and water pressures

摘要

By employing a thermal-hydro-mechanical bond contact model of Methane Hydrate Bearing Soil (MHBS), this paper uses the Distinct Element Method (DEM) to capture the formation of shear bands in MHBS under different temperatures and water pressures. A series of biaxial compression test simulations were performed to analyze the effects of temperature and water pressure on MHBS by examining mechanical behavior and characteristics of shear bands. The results show that the peak strength of MHBS increases with decrease of temperature and increase of water pressure. Shear bands develop after peak stress with numerous bonding breakage. The characteristics of shear bands in MHBS (i.e., pattern, thickness and inclination) are significantly affected by temperature and water pressure, which can be considered through a single lumped parameter L representing the distance from the current thermo-hydro state point to the phase equilibrium line of methane hydrate.