海底峡谷弱稳定沉积物推动式剪切破坏传播及其对沉积地层的影响

浊流能够携带大量陆源沉积物沿着海底峡谷向深海输运，是“源-汇”系统的重要组成部分。以往研究主要关注浊流对底床沉积物的冲刷、携带作用，底床沉积物进入浊流体内维持了浊流继续运动的能力。而峡谷沉积物具有松软、高含水率的特性，在浊流冲击荷载下，弱稳定沉积物会发生推动式剪切破坏，并且这种破坏会逐渐沿着海底峡谷向下游传播。分析浊流导致弱稳定沉积物推动式剪切破坏传播（WSS-PSP模式），对研究沉积物在海底峡谷的运动过程、输运模式、沉积影响等具有重要引领作用，并可能对深水油气资源成层解释产生新的理论。本申请项目基于这一全新的模式，利用理论推导计算与室内实验相结合的方法，分析其破坏传播的力学机制，计算破坏的传播速度以及沉积物底床破坏后对线缆等结构物的作用力，揭示破坏发生后，沉积物的再悬浮及其所形成的二次浊流的输运能力，给出基于WSS-PSP模式的海底峡谷沉积物输运全过程解析，及其对深海沉积的影响。

Turbidity current can carry a large amount of land-based sediments to the deep sea along the submarine canyon, which is an important part of the "source-sink" system. Previous studies have focused on the scour effect of turbidity current on the bottom sediment. The bottom sediments enter the turbidity current and maintain the mobility of turbidity current. Under the impact load of turbidity current, the weakly stable sediments suffered shear failure due to their soft and high water content to gradually spread downstream along the submarine canyon. The turbidite induced weakly stable sediment push shear propagation (WSS-PSP model) explores sediment movement process, transport mode and sedimentary influence in submarine canyon to produce a new theory for the generation and interpretation of deep-water oil and gas resources. This application project uses the method of combining theoretical derivation and calculation with laboratory test to reveal the mechanical mechanism of damage propagation, calculate the propagation speed of damage and the force on cable and other structures after the damage of sediment bottom bed, reveal the resuspension of sediment and the transport capacity of secondary turbidity current formed after the damage, and analyze sediment transport in submarine canyon based on WSS-PSP model and its influence on deep-sea sedimentation.