波浪荷载作用下海床的液化及参数分析

Momentary liquefaction and parametric analysis of seabed under wave loadings

为研究波浪荷载作用下海床的液化和其主要影响因素,基于线性水波理论和Biot波动理论,得到波浪荷载作用下海床土体中孔隙水压力和有效应力的解析表达式。以海床的液化深度作为主要评价指标,选择合适的液化判别方法,通过算例分析得出海床在不同水波和土体物理力学性质参数时的瞬时液化深度。结果表明:水波和海床的物理力学性质对海床液化深度影响较大,如水波的周期、水深、海床土体的强度、渗透率、泊松比、流体的压缩性等,其中波浪周期和海床的剪切模量、渗透率对海床的液化深度影响最大,其他参数在一定变化范围内对海床的瞬时液化影响较为明显。根据数值分析结果,提出了海床液化的防治措施。

In order to investigate the liquefaction of seabed and its main influential factors, the explicit expressions of excess pore pressure and effective stresses of seabed soil under wave loadings are obtained using the theory of linear water wave and Biot’s dynamic equilibrium equations. By taking the liquefaction depth of seabed as the main evaluation index and choosing a reasonable liquefaction discriminant method, the momentary liquefaction depth of seabed under different physical and mechanical parameters of water wave and seabed is calculated through numerical examples. The results show that the liquefaction depth of seabed is significantly influenced by the physical and mechanical properties of water wave and seabed, such as water wave period, water depth, soil strength, permeability, Poisson’s ratio, and fluid compressibility. The wave period, shear modulus, and permeability coefficient of seabed have the greatest influence on the liquefaction depth of seabed, while other parameters have certain effects on the momentary liquefaction depth of seabed. Based on the numerical results, the prevention and control measures of seabed liquefaction are suggested.