Instability analysis and numerical simulation of the dissociation process of methane hydrate bearing soil

Methane hydrates have been viewed as a new potential energy source, since a large amount of methane gas is trapped inside the hydrates. It is, however, well known that dissociation process of methane hydrate may lead to unstable behavior such as large deformation, uncontrollable gas production etc. A linear instability analysis was performed in order to investigate which variables have a significant effect on the onset of the instability of methane hydrate bearing soils with a simplified viscoplastic constitutive equation subjected to dissociation. Then, we conducted a numerical analysis of gas hydrate bearing soil with dissociation in order to investigate the effect of the rate of hydrate dissociation on the system. From the numerical results, the larger pore gas pressure and pore water pressure are produced and they diverge when the methane hydrate dissociation rate is relatively higher.