Study On The Stability Of Submarine Slopes Considering Dissociation Of Gas Hydrate

Submarine landslide is one of the most dangerous marine geological disasters,and gas hydrate dissociation is considered to be an important factor led to submarinelandslide. As the submarine environment is invisible and unpredictable, most of thestudies on the instability of submarine slope are carried out afterward. With thelarge-scale nonlinear finite element software ABAQUS, the stability of submarineslopes with gas hydrate is analyzed by using the strength reduction method in thisthesis. The safety factor of slope, the position of sliding surface, displacement, stressand other informations can be obtained, and these are significant for the furtherresearch and prevention of submarine landslide caused by hydrate dissociation.Themain works does in this thesis are as follows.1. The large nonlinear finite element software ABAQUS is briefly introducedfirstly. The principle of strength reduction method and the selection of yield criterionare also presented. Meanwhile, the feasibility of strength reduction method based onABAQUS in slope engineering is verified.2. Three different kinds of submarine slopes are simulated, and the safety factorsof homogeneous, polygonal and multilayer submarine slope are calculated by usingthe finite element strength reduction. And then the plastic zone and displacement aregiven. The calculated results are analyzed and the main factors that can influence thestability of submarine slope.are summarized.3. The mechanism of submarine landslide caused by hydrate dissociation isanalyzed briefly. By using the finite element strength reduction method, a calculationmodel for submarine slope is built to consider the influence of gas hydrate. The safetyfactors of submarine slope with different dissociation extent of gas hydrate arecalculated, and the plastic zone, the position of sliding surface, displacement, stressand other informations of instability are also obtained. Based on the analysis ofcalculation results, the influence of gas hydrate dissociation on the stability ofsunmarine slope is studied. It is proved preliminary that the finite element strengthreduction method can be applied to the stability analysis of submarine slope. 4. A real submarine slope with gas hydrate is simplified to a calculation model.Two calculation schemes are used to simulate the hydrate dissociation caused byartificial factors and natural factors, and the influences of hydrate dissociation onsubmarine slope are analyzed. It can be as a reference for the prevention of submarineslopes caused by hydrate dissociation.