考虑非线性孔隙流的近海结构物海床地基内波致渐进液化研究

项目名称： 考虑非线性孔隙流的近海结构物海床地基内波致渐进液化研究

项目编号： No.41472291

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 地质学

项目作者： 叶剑红

作者单位： 中国科学院武汉岩土力学研究所

项目金额： 98万元

中文摘要： 我国近海建有大量的海洋结构物，如防波堤、海底管线。由于受无休止的波浪作用，海洋结构物的海床地基极易发生液化导致结构物失稳。研究波-海床-结构物相互作用机理，及海床地基的液化对工程设计极具意义。由于受技术手段限制，前人的研究具有三个方面不足，表现为:(1)研究波-结构物作用时一般没有考虑海水和海床内孔隙水的交换，（2）解耦的解析或数值模型难以真实地描述波-海床-结构物之间的非线性作用机理，（3）难以考虑海工结构物或粗砂海床内的非线性孔隙流。本项目将致力于发展一个更为完善的耦合模型，弥补前人模型的不足。本研究首先修正经典的Biot方程，使之能够考虑孔隙介质内的非线性孔隙流，并采用有限元进行程序化，利用渗透实验加以验证。之后将该修正的Biot方程和VARANS方程进行耦合，形成用于波-海床-结构物相互作用的耦合模型FSSI-CAS，并采用水槽试验验证所发展的模型，最终应用于大尺度工程问题的计算。

中文关键词： 海洋工程地质；近海岩土工程；多场耦合；非线性孔隙流；水槽模型试验

英文摘要： There are a great number of offshore structures, such as breakwater and marine pipeline, have been constructed in the offshore area of China. Due to the unceasing wave loading in the offshore environment, the offshore structures are vulnerable to the wave-induced residual liquefaction in seabed foundation. It is significantly meaningful to investigate the wave-seabed- structures interaction mechanism, and the wave-induced liquefaction of seabed foundation for the engineering design.Actually, there are always some unavoidable drawbacks in the previous investigations. They are repectively (1)the exchange between the sea water and the pore water in porous seabed can not be considered when investigating the fluid-structures interaction; (2) the uncouped analytical models and numerical models can not describe the interaction mechanism between the wave, seabed and offshore structures; (3) the nonlinear porous flow in offshore structures or coarse sand bed is not taken into consideration. In this program, a new coupled numerical model will be developed to thoroughly overcome the drawbacks in previous investigations. Firstly, the classic Biot's equation will be modified to consider the nonlinear porous flow in large particle size porous media with large void. The finite element method (FEM) is adopted to discretize the modified Biot's equation, and the corresponding program codes will be developed; and permeation experiments is used to the verify the modified Biot's equation and the program codes developed. Secondly, adopting a kind of coupling algorithm of iteration, the modified Biot's equation and the Volume Average Reynolds Average Navier Stokes (AVRANS) equation are coupled together, to form a new coupled numerical model FSSI-CAS for the problem of wave-seabed-structures interaction.Adopting the wave flume experiments in Lab, the developed coupled numerical model FSSI-CAS will be validated. Finally, the developed coupled numerical model FSSI-CAS is applied to the large-scale engineering problems.

英文关键词： marine engineering geology;offshore geotechnical engineering;multiphysics;nonlinear porous flow;wave flume test