Composite model to reproduce the mechanical behaviour of Methane Hydrate Bearing Sediments

摘要

This paper describes the fundamental hypothesis and the formulation of a newconstitutive modelrnto cope with the mechanical behaviour of methane hydrate-bearing sediments.The model is based on a compositernapproach that defines the mechanical response of mineral skeleton and hydrate bond network independently.rnThe proposed model represents the transitional behaviour of MHBS by coupling two independent constitutivernmodels under certain strain compatibility conditions and mass and energy considerations. CASM elasto-plasticrncritical state model has been chosen to describe the matrix response and the bonding structure follows a damagernmodel. In order to overcome the technical challenges of natural gas production and the geotechnical problemsrnrelated with its complex rheological response, the constitutive model simulates the global stress-strain responsernof the composite medium and allows to assess methane hydrate dissociation on the basis of the stress state andrntemperature prevailing locally within the hydrate component.