| Submarine landslide is a special geological phenomenon, occurring in the development of a set of sedimentary strata, which is developed on the bottom of the sea floor, or the sea floor subjected to the gravity and other external stresses. Compared with the continental slope, the sea coast is critically difficult to be monitored and prevented due to the presence of the overlying water. This has attracted more and more attentions to study the development of many marine. Caused by multiple continental slope near the submarine slope instability of important factors, natural gas hydrate dissociation of excess pore water pressure is considered to be one of the most important aspects. There is a close connection between the instability of the submarine slope and the hydrate dissociation, which has been proved by many domestic and foreign research results. The relevant model is established and analyzed, which provides a basis for the prevention of the instability of the seabed slope caused by the hydrate dissociation. In this thesis, the research status of the hydrate dissociation and the formation of the excess pore water pressure are briefly analyzed, the following work has been accomplished:1. The basic principle and the selection of yield criterion for the finite element software ABAQUS and the finite element strength reduction method are briefly introduced, and the feasibility of finite element strength reduction method based on ABAQUS is verified in the slope engineering.2. An ideal model of the seabed energy and soil slope is established, using the finite element strength reduction method, the stability of the soil slope stability is analyzed by considering the weakening of the natural gas hydrate.3. An equivalent method is proposed to consider the influence of natural gas hydrate dissociation on the slope stability of the seabed; a suitable pore pressure model is chosen to calculate the excess pore pressure generated by natural gas hydrate in different amounts; on the basis of the above work, the stability analysis of the ideal slope model of seabed energy soil under the influence of pore pressure is further considered.4. The finite element model of the typical slope section of the well sites are set up, considering the effect of the pore pressure caused by hydrate dissociation, and quantitative analysis the geological disaster caused by gas hydrate dissociation(mainly submarine landslide). In this study, the simulation on the formation of submarine slide, the analysis and the evaluation of the stability of the submarine slope in the target area are performed. |
PDF Full Text Request