基于现场原位观测的黄河水下三角洲海底滑坡启动过程与控制因素研究

Submarine landslides in the subaqueous Yellow River Delta often take place on gentle slopes where the average gradient is less than 1°，which may cause pipeline rupture in Shengli Oilfield. The spatial distribution, shape of submarine landslides in the subaqueous Yellow River Delta have been obtained by marine geophysical exploration methods in the previous studies. However, the startup process and controlling factors of submarine landslides are not yet clear, which hinders the cognition of submarine landslides mechanism and needs to be verified. The objective of this project is to reveal the startup process of submarine landslides through in-situ long-term observation. The observation content included ocean dynamics, the pore water pressure in the sediments, the sediment strength and the slope deformation. In addition, based on the in-situ long-term observation, the controlling factors of submarine landslides are studied through the combination of the engineering geological survey and geotechnical test. The results of the study are intended to reveal the start-up process of low-angle submarine landslides triggered by oceanic dynamics, quantitatively assess the role of marine dynamics in the control of sediment pore pressure and strength changes on landslides, and establish methods for the prediction and early warning of low gradient landslides in the Yellow River subaqueous delta. It provides scientific guidance for the prevention and control of geological disasters in marine engineering activities and has significant scientific significance and application value.

现代黄河水下三角洲海底滑坡，发生在平均坡度小于1°的低缓斜坡上，导致胜利海上油田管缆折断。以往研究利用海洋地球物理探测手段，确定了海底滑坡的空间分布及形态特征，但对滑坡启动过程与控制因素尚不清楚，阻碍了对海底滑坡机制认识及滑坡灾害的科学防控。本项目通过现场原位长期观测，研究黄河水下三角洲海底滑坡的启动过程，观测内容包括：海洋动力要素波浪、潮汐、海流，沉积物孔隙水压力累积消散，沉积物强度变化，海底斜坡变形滑动；通过对原位长期观测数据的分析，结合观测点工程地质调查与沉积物取样测试，探究黄河水下三角洲海底滑坡的控制因素。研究结果可以揭示海洋动力作用诱发低角度海底滑坡的机制，定量评价海洋动力作用导致的沉积物孔压累积与强度变化，建立黄河水下三角洲海底滑坡预测与预警方法，为海洋工程活动中地质灾害防控提供科学指导，具有显著的科学意义与应用价值。

现代黄河水下三角洲发育多种海洋地质灾害，大都受控于波致海床失稳破坏。以往研究利用海洋地球物理探测手段，确定了海底滑坡的空间分布及形态特征，但对滑坡启动过程与控制因素尚不清楚，阻碍了对海底滑坡机制认识及滑坡灾害的科学防控。本项目通过现场原位长期观测，研究黄河水下三角洲海底滑坡的启动过程，观测内容包括：海洋动力要素波浪、潮汐、海流，沉积物孔隙水压力累积消散，沉积物强度变化，海底斜坡变形滑动；通过对原位长期观测数据的分析，结合观测点工程地质调查与沉积物取样测试，探究黄河水下三角洲海底滑坡的控制因素。研究结果阐明了波致海床变形滑动的启动、演化的过程与物理机制，定量评价了海洋动力作用导致的沉积物孔压累积与强度变化，建立了黄河水下三角洲海底滑坡预测与预警方法，为海洋工程活动中地质灾害防控提供科学指导，具有显著的科学意义与应用价值。