波浪作用下海床液化-重固结移动边界分析模型及离心模型试验验证  

Development and validation of a modified moving boundary model to simulate liquefaction-solidification behaviors of seabed under wave loading

作　　者：苏思杨 孔德琼[1,3] 吴雷晔 朱斌 SU Si-yang;KONG De-qiong;WU Lei-ye;ZHU Bin(Center for Hypergravity Experimental and Interdisciplinary Research,Zhejiang University,Hangzhou 310058,China;Institute of Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学超重力研究中心,浙江杭州310058 [2]浙江大学岩土工程研究所,浙江杭州310058 [3]浙江大学建筑工程学院,浙江杭州310058

出　　处：《岩土工程学报》2022年第6期1156-1165,F0003,共11页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52071289,51988101)。

摘　　要：改进了已有的移动边界分析模型,考虑了流体黏度和有限海床深度对波浪作用下海床液化-重固结行为的影响。采用层流Navier-Stokes方程替换原模型中的势流方程,从而合理描述液化/流态化海床和外部流体形成的黏性双层流体系统;同时,在控制方程中采用了有限深度海床的波致剪应力计算模型。通过与砂土和黏土中波浪–海床相互作用离心模型试验验证了该模型的有效性。结果表明液化海床尤其是砂土海床具有较大黏度,忽略流体黏度会高估液化/流态化海床表层的运动幅值;海床深度边界显著影响海床内部波致孔压分布规律,与以往无限深度海床计算结果存在较大区别。同时,该模型能够较好反映波浪作用下海床地基重固结后硬壳层的形成机制,以及海床地基内部孔压幅值放大效应。An analysis method is proposed based on an existing moving boundary model to assess the response of seabed under wave loading,accounting for the effects of fluid viscosity and the boundary of the seabed.The potential flow equations in the original model are replaced by the laminar Navier-Stokes equations so that the viscous two-layer fluid system consisting of the liquefied/fluidized seabed and the water above it can be described reasonably.Meanwhile,the source term in the governing equations for the wave-induced shear stress calculation model is updated to consider the effects of the seabed boundary.The centrifugal model tests are carried out to validate and calibrate this model,as well as to demonstrate its capability of modelling the liquefaction/solidification of the seabed,in terms of the development of excess pore pressure and void ratio.The results show that the liquefied seabed has a high viscosity,which may lead to overestimation of the seabed movement amplitude,especially for sandy soils.Comparisons between the calculations based on seabed with infinite and finite depths show discernible discrepancies,thus it is suggested the effects of the seabed boundary should be considered in modelling.This model is also found to be capable of capturing the increase in soil strength within a certain depth after wave loading and the amplification of the pore pressure amplitude.

关 键 词：波浪作用 移动边界模型 离心模型试验 砂土 软黏土 

分 类 号：TU43[建筑科学—岩土工程]