考虑土骨架加速度效应的海床动力反应及其影响因素分析

由Biot二维广义动力固结理论的形式基本控制方程出发,忽略孔隙流体的加速度,提出了饱和海床动力反应的时域有限元数值解法.联立静力平衡条件和Biot固结方程的退化法所得到的数值解可视为其特例.在比较算例中,退化法得到的超静孔压和有效应力幅值沿海床深度的分布与解析解一致.一般情况下,土骨架的加速度对海床的有效应力和超静孔压影响很小,控制方程可以退化为Biot理论.成层海床上部的粗砂层不会使超静孔压幅值在海床表面下较浅的深度内迅速衰减,难以改变海床的瞬时循环液化深度.

Numerical analyses and parametric studies of dynamic response of seabed considering the effect of soil skeleton acceleration

Based on the u-p form of the gener alized formulation of two-dimensional Biots theory of dynamic consolidation,the finite element numerical procedure in time domain is developed to evaluate dynamic response of saturated seabed.The governing equations which are composed of static equilibrium conditions and Biots consolidation equation can be regarded as a special case.In comparative examples,the results from the degenerated method proposed agree well with the analytical solutions.In general,the effect of soil skeleton acceleration on effectivest resses and pore pressure can be neglected and the governing equations can be expressed by Biots theory. The upper coarse sand layer of layered seabed will not reduce the amplitudes of pore pressure remarkably at the shallow zone near the seabed surface,therefore the possible maximum liquefaction depth will not change.