Abstract: In view of the insufficient recognition of the failure mechanism of submarine clayey slope induced by gas hydrate dissociation, the effect of gas on submarine slope after gas hydrate dissociation was simulated by means of venting. Furthermore, multiple of experiments were carried out under different combinations of soil strength, embedment depth of gas hydrate, flow rate and dissociation zone. Combining with the image processing, the deformation and the evolutionary process of slope surface and slope body were deeply investigated. The deformation and failure characteristics of submarine clayey slope induced by hydrate dissociation were initially revealed. On this basis, a limit equilibrium method was used to establish the critical pressure analytic expression of submarine slope failure, which is theoretically explained the critical pressure value in the failure process of slope deformation. The results show that the deformation and failure processes of the submarine slope are divided into four stages: the accumulation of air pressure, the elastic compression of soil, the upheaval failure of slope, and the deformation stability of slope. Although, there is a deviation between the calculated and experimental results of gas critical pressure, it can reflect the true level of the critical pressure to some extent. The research results can provide some references for the further understanding of the deformation and failure mechanism of submarine clayey slope induced by gas hydrate dissociation, and the developments of the stability analysis theory and evaluation method.

Key words: gas hydrate; submarine clayey slope; deformation and failure mechanism; model experiment