地震荷载作用下海底管线周围砂质海床的稳定性分析  

STABILITY ANALYSIS OF SANDY SEABED AROUND SUBMARINE PIPELINES UNDER SEISMIC LOAD

作　　者：栾茂田[1] 张小玲[2] 张其一[2] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024 [2]大连理工大学土木水利学院岩土工程研究所,辽宁大连116024

出　　处：《岩石力学与工程学报》2008年第6期1155-1161,共7页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金重点项目(50439010);国家自然科学基金资助项目(50579006,50179006);教育部跨世纪优秀人才培养计划研究项目(教技函[1999]2号)

摘　　要：地震荷载作用下海床液化是海底管线失稳的主要原因之一。建立地震荷载作用下海底管线周围砂质海床液化问题的有限元模型,利用先进的土工静力–动力液压三轴–扭剪多功能剪切仪,将在不排水循环扭剪试验条件下得到的孔隙水压力增长模式作为考虑地震循环作用所引起的孔隙水压力源项引入到二维动力固结方程中,基于有限元方法对推广的固结方程进行数值求解,得到地震荷载作用下砂质海床中累积孔隙水压力的发展过程与变化规律。通过变动参数计算研究砂质海床土性参数和管线几何尺寸对由地震所引起的管线周围海床中累积孔隙水压力分布的影响,进一步对管线周围砂质海床的液化势进行评判。通过计算分析发现,土的渗透系数对由地震所引起的管线周围砂质海床中的累积孔隙水压力比具有显著影响,而管线半径只影响管线周围海床的累积孔隙水压力比分布,在离开管线一定距离之外,其影响可以忽略。The liquefaction of seabed under seismic load is one of the main reasons that govern the global stability of submarine pipeline. A finite element numerical analysis method for liquefaction around a buried pipeline in sandy seabed under seismic load is presented. The advanced soil static and dynamic universal triaxial and torsional shear apparatus is employed to perform torsional shear tests subjected to cyclic loading. The mode of dynamic increase of pore water pressure under undrained conditions gained from tests is incorporated with two-dimensional dynamic consolidation equation; and a numerical procedure based on FEM is developed to assess the accumulative pore water pressure. By numerical computation, the accumulation process of pore water pressure and liquefaction potential of sandy seabed soil under seismic load can be evaluated. Based on the presented numerical model, the effects of sandy soil characteristic parameters and pipeline geometry on the seismic-induced accumulative pore water pressure around submarine pipeline and along the depth of seabed are studied. By the computation and analysis, it is found that the effects of soil permeability coefficient on the seismic-induced accumulative pore water pressure ratios of sandy seabed around the pipeline are remarkable. Otherwise, the radius of pipeline only influence the accumulative pore water pressure ratios of sandy seabed nearby the pipeline; and the effects of pipeline can be neglected in the region of seabed far away from the pipeline.

关 键 词：土力学 海底管线 地震荷载 累积孔隙水压力 液化 

分 类 号：TU441[建筑科学—岩土工程]