海底滑坡中水滑的触发机制及其危害性的物质点法研究

Submarine landslides are one of the most hazardous agents through which vast volumes of sediments are transported across the slopes. Hydroplaning, involving complicated interaction between the sliding mass and the ambient water, is the main reason for the very quick and long-distance runout of the submarine landslides. This project uses a novel numerical method, material point method (MPM), to investigate the mechanism and consequence of hydroplaning: the sliding mass is simulated with soil dynamics in effective stress mode, the ambient water is analysed with hydrodynamics, and the two components are coupled by considering the pressure continuity at the soil-fluid interface. The coupling analysis is accelerated with massive GPU parallelisation, which allows to mimic the runout of full-scale submarine landslides. The mechanism of hydroplaning is investigated by analysing the runout velocity and the hydro-pressure of the frontal sliding mass, and occurrence occasion of the hydroplaning is quantified. The control factors for the development of hydroplaning are determined, which are used to shape an empirical method to assess the probability of hydroplaning. Then real cases of submarine landslides are back-analysed to assess the occurrence in the history of the slides. The runout morphologies are discussed, in which the mechanism of outrunning blocks is clarified and an integrated method is formed to predict the long-distance runout of submarine landslides.

海底滑坡可以沿斜坡搬运大量沉积物，是危害最大的海洋地质灾害之一。水滑是海底滑坡高速和长距离滑动的主要原因，涉及复杂的滑坡体-环境水相互作用。本项目拟采用新型数值方法物质点法对水滑的触发机制和危害性进行研究，对滑坡体采用土动力学进行有效应力分析，对环境水采用流体动力学模拟，考虑两者之间的压力平衡进行耦合分析。采用大规模GPU并行对计算进行加速，实现对真实尺度下海底滑坡的模拟。通过对滑坡体的滑动速度和前端动水压力的探讨，探明水滑的触发机制，并对不同尺度条件下水滑的触发时机进行定量分析。在此基础上，确定影响水滑发展的控制因素，形成快速评估水滑发生可能性的经验方法。然后对真实海底滑坡案例进行反分析，探讨不同地质条件下水滑发生的可能性。对水滑发生后滑坡的滑动形态展开讨论，明确滑出块体的产生机制，形成完整的海底滑坡长距离滑动的预测方法。

海底滑坡可以沿斜坡搬运大量沉积物，是危害最大的海洋地质灾害之一。水滑是海底滑坡高速和长距离滑动的主要原因，涉及复杂的滑坡体-环境水相互作用。本项目采用新型数值方法物质点法对水滑的触发机制和危害性进行研究，对滑坡体采用土动力学进行有效应力分析，对环境水采用流体动力学模拟，考虑两者之间的压力平衡进行耦合分析。采用大规模GPU并行对计算进行加速，实现对真实尺度下海底滑坡的模拟。通过对滑坡体的滑动速度和前端动水压力的探讨，探明水滑的触发机制，并对不同尺度条件下水滑的触发时机进行定量分析。在此基础上，确定影响水滑发展的控制因素，形成快速评估水滑发生可能性的经验方法。对真实海底滑坡案例进行反分析，探讨不同地质条件下水滑发生的可能性。对水滑发生后滑坡的滑动形态展开讨论，明确滑出块体的产生机制，形成完整的海底滑坡长距离滑动的预测方法。