Numerical simulation of macro-mechanical properties of deep-sea methane hydrate bearing soils by DEM

First, the micro-bond contact model proposed by Jiang et al. is employed to describe micro-bond contact mechanical properties of hydrate between methane hydrate bearing soil particles. Second, in order to introduce the model to the DEM commercial software PFC^2D, a program interface is established by using C++ to program the model. Third, based on the saturation of hydrate, cemented width is obtained through a simplified method, and micro bond parameters are determined. Finally, based on the micro parameters of methane hydrate, many biaxial tests with different hydrate contents are carried out to simulate the mechanical properties of the soil. In addition, comparisons are made between triaxial experimental observations done by Masui et al. and numerical simulation from aspects of stress-strain, volumetric strain and elastic modulus of the soil. The results show that the macro-mechanical properties of deep-sea methane hydrate bearing soils are reflected reasonably by using the selected bond contact model and micro bond parameters, that the peak shear strength and elastic modulus of deep-sea energy soils increase with the increasing content of hydrate, and that the volumetric dilate is more pronounced.