Study on Sampling Disturbance in Methane Hydrate Bearing Sediments by DEM Analysis

Abstract Sampling process can result in disturbance to the micro-structure of soil samples and further affect their macro mechanical properties. This study aims at investigating the disturbance due to sampling the methane hydrate bearing sediments (MHBS) via distinct element method (DEM). Conventional triaxial tests for samples with different initial conditions (i.e. in-situ effective stress σ v , phase equilibrium parameter L , and the hydrate saturation S mh ) are simulated by DEM. Based on the simulated data, the effect of initial conditions is quantitatively analyzed. The results show that the disturbance induced by sampling process to samples can degrade secant modulus E 50 , yield strength q y , and cohesion c . The macro and micro disturbance degree will reduce with decrease in σ ’ v and increase in both L and S mh . Besides, the typical range of initial condition where the effect of sampling disturbance on the macro mechanical properties of MHBS samples can be ignored is obtained.