DEM analysis on formation of shear band of methane hydrate bearing soils

Methane hydrate (MH) decomposition and mining will worsen the mechanical behavior of methane hydrate bearing soil (MHBS) and cause a series of geotechnical problems. Therefore, in order to facilitate safe exploitation of MH, it is crucial to understand the strength and deformation characteristics of MHBS. Based on the bond model of MHBS, the distinct element method (DEM) is used in planar biaxial compression tests to analyze the formation of shear band as well as some micro and macro variables of MHBS within and outside the shear band. The results show that methane hydrate increases the strength of MHBS and leads to strain-softening behavior; the shear band is fully developed after the peak stress, accompanied by massive bond breakage and localization of other micro variables; the micro and macro variables within and outside the shear band differ. Besides, with the increase of axial strain, the micro structure of MHBS changes.