Evolution of Coordination Number of Methane Hydrate Bearing Sediments during Quasi-static Shearing

Quasi-static shearing of methane hydrate bearing sediments (MHBS) was investigated by performing numerical tests using distinct element method (DEM) so as to comprehensively understand mechanical properties of MHBS. Stress-strain response and dilation behaviour of numerical tests were presented and compared with that of physical experiments. And then an examination of the evolution of coordination number (CN) during shearing was also presented, as well as its relation to anisotropy of contact orientations. The research results led us to conclude that (i) DEM can effectively capture the main characteristics of strength and deformation of MHBS; (ii) Distribution of CN shows obvious heterogeneity which is closely associated with shear bands; (iii) The average CN has a strong correlation with total number of contacts, and could be further interpreted from the point of view of anisotropy of contact orientations;