ThreeDimensional Distinct Element Novel SamplePreparing Method and Mechanical Behavior for PoreFilling Type of Methane HydrateBearing Soil

Abstract:

In view of the morphology of porefilling type of methane hydratebearing sediment (MHBS), this paper proposed a new technique for generating porefilling type of MHBS. Marine sandy sediments containing porefilling type MH particles can be considered as a class of special granular materials that present apparent obvious discontinuity characteristics. To numerically simulate such materials, the distinct element method (DEM) can be used by modeling MH particles as agglomerates of spheres cemented together and filled into the pores of soil skeleton based on the specific MH saturation. The drained triaxial compression tests with different MH saturation and effective confining pressures were conducted to analyze the mechanics, deformation characteristics and contact fabric of the porefilling type of MHBS. The results show that the influence of MH saturations on the initial elastic modulus and deviator stress is relatively small. The volume shrinkage decreases with increasing MH saturations under the same effective confining pressure while the strength and the volume shrinkage increase with the effective confining pressure increasing under the same MH saturation. The shear dilatancy angle almost linearly decreases with the increase of effective confining pressure, and it linearly increases with MH saturations increasing. The grain contact direction deflects to the vertical direction with the increase of axial strain.