地震触发海底滑坡流动运移规律的试验研究

Submarine landslide is a kind of extremely destructive marine geological hazard, and earthquake is an important trigging factor of it. Under the background of accelerating exploration the resources of China's offshore oil and gas, earthquake triggered submarine landslides will cause a huge threat to the security for the exploration and development of offshore oil and gas resources. Therefore, the research on migration law of earthquake triggered submarine landslide will be a major strategic need of the maritime safety engineering. The project takes submarine soil landslide, which is under the effect of earthquake, as the research object. First, using the ring-shear test and dynamic triaxial test to study the strength decaying law and non-Newton liquid feature of submarine soil, the flow characteristic and seismic intensity and clay content impact on flow characteristic will be studied. Second, using shaking table and flume to simulate the moving process and morphological characteristics of submarine landslides under the effect of the earthquake, the migration characteristics and the seismic intensity and clay content impact on the migration characteristics will be studied. Third, comprehensive analysis of the result, the migration law of earthquake triggered submarine landslide will be pointed out. The research results can effectively improve the subject of Marine Geology Engineering, and provide a scientific theoretical foundation for earthquake triggered submarine landslide prevention. This research will be a great value work and has an important theoretical significance for the safety of our marine engineering geology.

海底滑坡是一种极具破坏力的海洋地质灾害，地震是其最主要的一个触发因素。在我国海洋油气资源加速开发的背景下，地震触发海底滑坡将对海上油气资源勘探开发的安全构成巨大的威胁，对地震触发海底滑坡流动运移规律的研究已成为国家海洋工程安全领域的重大战略需求。本项目针对地震触发的海底土质滑坡，从土体及滑坡体两个尺度，采用环剪试验和动三轴试验，研究地震作用下海底土体的强度衰减规律和非牛顿流体特性,揭示海底土体的流动特性及地震强度和粘粒含量对流动特性的影响；采用振动台-水槽试验，研究地震作用下海底滑坡体的运动过程及滑坡形态特征，揭示海底滑坡的运移特征及地震强度和粘粒含量对运移特征的影响；通过分析海底滑坡的流动特性及运移特征，揭示地震触发海底滑坡的流动运移规律。研究成果可有效促进海洋地质工程学科的发展，为地震触发海底滑坡灾害的防治提供科学的理论依据，对提高我国海洋工程地质安全性具有重要的理论意义和工程价值。

海洋环境相比陆地环境十分复杂，海底滑坡的研究目前仍处于研究初始阶段，与陆地滑坡相比，无论从形成条件、启动机制，还是运动学特征等都没有达成一致性共识。地震触发海底滑坡是海底滑坡最常见的类型。在我国海洋油气资源加速开发的背景下，地震触发海底滑坡将对海上油气资源勘探开发的安全构成巨大的威胁，对地震触发海底滑坡流动运移规律的研究已成为国家海洋工程安全领域的重大战略需求。本项目针对地震触发的海底砂土滑坡，以室内试验为主要研究手段，从土体及滑坡体两个尺度对地震触发海底滑坡的流动运移规律进行研究。采用环剪试验，研究了海床砂土在不同剪切方式下的应力-应变特征、沉降变形特征和残余强度特征，分析了海床砂土的强度衰减规律，得出采用多级剪切试验测试海底滑动带残余强度参数较为合适。采用动三轴试验，研究了海床砂土的孔压比-振次关系、应力-应变滞回圈变化规律和动强度特征，分析了海床砂土的动力特性，得出了砂土的非线性和粘滞性特征。采用自制的振动台-水槽试验装置，探索了地震触发海底滑坡的模型模拟试验方法及仪器，根据运动过程中的海底滑坡体形态，将海底滑坡运动过程分界为三个阶段。从滑坡体组成成分、颗粒分散性、两相流相互作用、滑床沿程阻力、滑坡体运动速度、冲击力、地震强度等方面，研究了海底滑坡的运移特征及影响因素。研究成果可有效促进海洋地质工程学科的发展，为地震触发海底滑坡灾害的防治提供科学的理论依据，对提高我国海洋工程地质安全性具有一定的理论意义和工程价值。