风暴事件作用下黄河水下三角洲浮泥层的形成与运动过程研究

Fluid mud layers (FML) are the undersea region where fine sediments are gathered on the seabed surface under specific marine hydrodynamic conditions. During the extreme storm events, the seabed sediment resuspension supported by wave-induced shear stress, and their gravity-driven transport within FML are the common concerned hotspot of marine science and engineering field. Limited by methods of observation and analysis, the role of wave-induced liquefaction and pore pressure support for formation and movement of FML has not been considered in existing researches. This proposal performs a detailed research into its processes under storm events on the Yellow River subaqueous delta, where submarine cable are widely distributed. By conducting field investigation and sampling, samples tests and model experiments, in-situ long-term observations, and numerical simulation, this proposal will study the engineering properties and observation method of FML on the Yellow River subaqueous delta; mechanism and key factors in the formation of FML under storm events; and quantitative assessment of FML. The research aims to reveal the mechanisms of formation and movement of FML and establish the quantitative prediction methods. It has important scientific contribution in better understanding the process of gravity-driven flows on small slopes, and is of important value in assessing the engineering safety of exploitation activities of offshore oil fields in the Yellow River delta, China.

海底浮泥层是细颗粒沉积物在特定海洋动力条件下聚集于海床表面形成的流体层。特别在极端风暴事件中，强波浪产生的剪切力支撑沉积物悬浮，并沿斜坡以重力流形式运动是科学与工程界共同关注的热点问题。已有研究受限于观测与分析方法，尚未考虑波土相互作用的液化响应与孔压支撑在其形成与运动演化中的角色和贡献。本项目针对风暴事件作用下浮泥层的形成与运动过程这一前沿科学问题，以海底电缆分布的黄河水下三角洲为研究对象，通过开展典型研究区现场调查与采样、样品测试与模型试验、原位长期观测、数值模拟计算，研究黄河水下三角洲浮泥层的工程特性与观测判定方法、风暴事件作用下浮泥层的形成机理与关键影响因素、黄河水下三角洲浮泥层沿坡运动的定量评估。研究成果将揭示风暴事件中浮泥层的形成与运动过程机理，并建立定量预测方法，对深入认识海底斜坡重力流过程具有重要科学意义，同时在黄河三角洲海上油田开采工程安全评价方面具有重要应用价值。