波浪作用下某防沙堤的动力固结有限元分析

Dynamic consolidation finite element analysis of a sediment-protecting dyke under ocean wave loading

基于饱和土动力固结理论,采用SWANDYNE II有限元分析程序预测一个梯形沉箱防沙堤在某设计波浪作用下的响应。采用Pastor-Zienkiwicz Mark III广义塑性模型模拟了海床土的循环应力-应变行为。通过动三轴试验,确定了主要的模型参数,分析中只考虑了波浪对结构的作用,忽略行波对海床表面的作用。动力固结有限元分析的结果定性上与常规的拟静力极限平衡分析方法一致,有限元分析定量给出了体系的位移、应力、孔隙水压力分布和结构位移随波浪持续时间的累积过程,其研究结果初步展现了动力固结有限元方法在近海和海岸岩土工程领域的广阔应用前景。

Based on the dynamic consolidation theory of saturated soil, the behavior of a caisson dyke under ocean waves was predicted using finite element analysis codes- SWANDYNE Ⅱ. The cyclic stress-strain behavior of seabed soil was modeled by a generalized plastic model, Pastor-Zienkiwicz Mark Ⅲ model, and cyclic triaxial tests were performed to calibrate the main model parameters. Only the action of ocean waves directly on the structure was considered, while the action of traveling waves on the surface of se＇abed was neglected in the analysis. The result of the dynamic response analysis was the same in nature as that of pseudo-dynamic limit equilibrium analysis. The dynamic response analysis also provided with the distribution of the displacement, stress and excess pore water pressure of the system, as well as the cumulative process of the. structure displacement with wave duration time. The broad prospect was presented of application of dynamic consolidation finite element analysis in offshore and coastal geotechnical engineering field.