The effects of methane hydrate dissociation at different temperatures on the stability of porous sediments

Based on a series of triaxial compression tests on methane hydrate-bearing sediments after a hydrate dissociation time of 0 h, 1 h, 6 h, 12 h, or 24 h, the mechanical properties of the sediments were studied during hydrate dissociation at different temperatures. The results showed that strain softening behavior appeared at higher temperatures in our work. The failure strength and initial yield strength both decreased with an increase in the methane hydrate dissociation time, and the rate of decline of failure strength was faster at higher temperatures. Mathematical expressions for the failure strength and the initial yield strength in terms of the dissociation time and the temperature were also proposed. Moreover, the Duncan-Chang constitutive model of methane hydrate-bearing sediments considering the influence of temperature and hydrate dissociation time was developed, and the validity of most of the calculated results was verified by experiment.