波浪作用下饱和砂质海床土体与管线相互作用规律研究  

Wave-induced interaction of saturated sandy seabed with pipeline

作　　者：王小雯 张建民[1,2] 李焯芬[1,2] WANG Xiao-wen;ZHANG Jian-min;LEE C F(State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China;Institute of Geotechnical Engineering, Tsinghua University, Beijing 100084, China)

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [2]清华大学岩土工程研究所,北京100084

出　　处：《岩土力学》2018年第7期2499-2508,2554,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金面上项目(No.51678346);国家自然科学基金项目(No.51079074)~~

摘　　要：针对波浪引起的饱和砂质海床土体和管线相互作用问题,将Biot动力固结理论与笔者课题组提出的砂土液化变形弹塑性本构模型相耦合,较为合理地再现了简谐波浪作用下较浅饱和砂质海床中管线周围可液化海床土体的超静孔隙水压力瞬态累积变化规律与液化过程。数值计算结果与Sumer等的试验规律一致。结果表明:由于管线的存在,改变了饱和砂质海床液化区域的空间分布。液化首先由管线下部土体开始产生,随着波浪荷载的持续作用,液化区域沿着管线外壁向上演化;同时海床表层土体产生液化并向深层发展,最终管线周围土体都发生液化,这是导致空管上浮的主要原因。当饱和砂质海床中存在管线时,管线附近海床土体液化深度明显变深。超静孔压累积和渗透力变化的耦合作用是导致饱和砂质海床土体产生液化的原因。与将海床土体视为饱和弹性多孔介质相比,可考虑液化全过程的弹塑性动力分析能更为合理地揭示实际波浪作用下饱和砂质海床土体的渗流场和应力场的瞬态时空演变规律。This paper applies Biot＇s consolidation theory and an elasto-plastic constitutive model on the post-liquefaction deformation of sand to investigate the wave-induced dynamic interaction between pipeline and seabed. The numerical simulations can reasonably reproduce the accumulation of excess pore pressure and the process of soil liquefaction around the pipeline induced by linear waves in the liquefiable finite seabed. The numerical results show qualitatively consistent with Sumer et al.＇s results, and demonstrate conclusions as follows： The distribution of liquefaction in the seabed is significantly influenced by the pipeline, liquefaction first occurs at the seabed surface and underneath the pipeline, then transfers toward the soil surrounding the pipeline. Eventually, the entire sandy seabed around the pipeline liquefies, leading pipeline flotation. The degree of liquefaction in the soil around pipeline is intensified by pipeline. The soil liquefaction is induced by waves which is found mainly the combination of accumulation of excess pore pressure and seepage forces. The elasto-plastic method of dynamic analysis presents more rational result compared to the existing elastic method in simulating the changes of seepage field and stress field under wave actions for realistic ocean environment.

关 键 词：波浪 饱和砂质海床 管线 液化 弹塑性动力分析 

分 类 号：TU411[建筑科学—岩土工程]