波浪作用下海床动力反应有限元数值模拟与液化分析

摘要

基于二维广义动力Biot固结理论,提出了线性波浪作用下饱和弹性多孔介质海床动力反应的有限元数值解法.静力平衡条件和Biot固结方程组成的边值问题控制方程组可视为其特例.提出的数值模拟方法能够模拟多层非均质海床等复杂土质和地层条件,这是一般解析法难以处理的.讨论了波浪诱发海床液化的机理与液化判断准则,对比计算表明驻波造成的最大液化深度往往是推进波导致液化深度的数倍.%Based on the generalized formulation of two-dimensional Biot′stheory of dynamic consolidation, a finite element numerical method in time domain is developed to evaluate the dynamic response of the saturated elastic seabed subjected to the ocean wave pressure assessed based on the Airy′s linear wave theory. The gove rning equations which are composed of static equilibrium condition and Biot′s consolidation equation could be regarded as a special case. For complex geological conditions with nonhomogeneous soil profiles, such as multiple-layered or non -uniform seabed, the numerical method proposed has shown its more notable advan tages over the conventional analytical methods. The mechanism and the criterion of the wave-induced liquefaction are discussed briefly according to the trigger condition of liquefaction. It has been shown by comparative calculations that t he magnitude of the maximum liquefaction depth due to standing waves may be gene rally several times that of a progressive wave.