Distinct element modelling of constant stress ratio compression tests on pore-filling type methane hydrate bearing sediments

Abstract

The mechanical behavior of methane hydrate bearing sediments (MHBS) subjected to various stress-path loading is relevant to seabed subsidence or hydrate sediment strata deformation and well stability during the exploration and methane exploitation from methane hydrate (MH) reservoir. This study presents a numerical investigation into the mechanical behavior of pore-filling type MHBS along constant stress ratio path using the distinct element method (DEM). In the simulation, methane hydrate was modelled as agglomerates of sphere cemented together in the pores of soils. The numerical results indicate that the compressibility of MHBS is low before yielding but higher after. Bond breakage in MH agglomerates occurs during loading and the bond contact ratio decreases when the major principal stress increases. As for the fabric tensors, the minor principal fabric slightly increases to a constant value while the major principal fabric decreases to a constant value.