天然气水合物开采过程中海底斜坡失稳的粒子法模拟研究

海底斜坡失稳是天然气水合物勘探与开采工程中的关键问题，失稳造成的滑坡会给周围的海底工程与沿海居民造成不可估量的损失。由于海洋环境复杂多变，海底斜坡失稳的精确数值模拟一直未得到很好的解决。本项目拟基于拉格朗日(Lagrangian)框架下的梯度光滑法(Gradient Smoothing Method, GSM)，结合粒子位移技术，建立静水高围压下的海底斜坡失稳Lagrangian-GSM模型；在此基础上，引入水合物分解模型，研究不同失稳影响因素之间的非线性关联机制，发展多因素联合作用下海底斜坡失稳模型；采用高效计算方案，提高计算效率，实现对真实海洋环境下海底斜坡由失稳至滑坡这一大规模问题的数值模拟，探究海底斜坡多因素联合作用下的破坏模式，精准预报海底斜坡失稳的影响范围与强度，旨在为天然气水合物开采工程中海底斜坡失稳的研究提供理论基础与技术支撑。

Submarine slope instability is a key problem in gas hydrate exploration and exploitation engineering. The submarine landslide caused by slope instability can cause immeasurable losses to the surrounding submarine engineering and coastal residents. However, due to the complicated ocean environments, it has not been well solved for accurate simulating of submarine slope instability. This project develops Gradient Smoothing Method in the Lagrangian frame to solve the submarine slope instability problem. By combining with shifting particle technology, we establish the submarine slope instability Lagrangian-GSM numerical model under high confining pressure of static water. Besides, by introducing hydrate dissociation model, the nonlinear correlation mechanism of multiple instability factors is studied, and we propose the submarine slope instability algorithm under multiple factors combined loading. The calculation efficiency is improved by using high performance computing solutions, thus the large-scale physical process from submarine slope instability to landslide in real marine environment is simulated. The failure mode of submarine slope under multiple factors combined loading is investigated, and the scope and scale of submarine slope is predicted accurately. This project aims to provide the theoretical basis and technical support to the submarine slope instability investigation in gas hydrate exploitation engineering.