波浪诱发松散海床渐进式液化的数值分析

近海区域广泛分布着第四纪新沉积的松散海洋土，波浪荷载作用下松散海床会发生液化进而对近海结构物的稳定性存在巨大威胁。本文采用中国科学院流体-结构-海床相互作用数值计算模型FSSI-CAS 2D，选用Pastor-Zienkiewicz-Mark Ⅲ（PZⅢ）弹塑性本构研究了波浪诱发的松散海床液化问题。分析了波浪荷载引起的松散海床内超孔隙水压力、有效应力以及应力角的时程变化特性，并预测了松散海床的渐进液化过程。计算结果表明，波浪荷载作用下松散海床内残余孔压会累积增长，海床表面最先发生液化，然后逐渐向下发展至液化最大深度。同时指出海床内超孔隙水压力的竖向分布特征和应力角的变化时程均可以作为判断海床液化的间接参数。最后，通过应力状态分析，讨论了海床渐进式液化的发展过程和趋势。

Wave-induced progressive liquefaction in loosely deposited seabed

Quaternary newly deposited loose seabed soil widely distributes in offshore area in the world. Wave-induced residual liquefaction in loose seabed floor brings great risk to the stability of offshore structures in extreme climate. In this study, wave & current-induced residual liquefaction in loose seabed floor has been investigated comprehensively adopting FSSI-CAS 2D incorporating Pastor-Zienkiewicz-Mark Ⅲ(PZⅢ) soil model which is a validated integrated numerical model. The time history of wave & current-induced pore pressure, effective stress, stress angle are discussed. The variation process of progressive liquefactionis illustrated in detail. The computational results confirm that the wave & current-induced liquefaction in loose seabed soil is progressively downward, initiating at seabed surface. Besides, it is found that vertical distribution of oscillatory pore pressure, and time history of stress angle could be taken as indirect indicator to judge the occurrence of wave-induced residual liquefaction. The developing process of the progressive liquefaction is analyzed by stress statement data of seabed soil.