地震荷载作用下海底管线的动力反应分析

 地震荷载作用下海床中的孔隙水压力与有效应力是影响海底管线稳定性的主要因素。然而在目前的海床动力响应分析中一般将管线假定为刚性，并不能合理地考虑海床与管线的相互作用效应，同时也没有考虑地震荷载作用下海床边界的等效处理。为此，基于Biot动力固结理论建立海床–管线相互作用的计算模型，以大型有限元软件ADINA为平台对El Centro地震波作用下的海底管线的动力响应以及管线周围土体的孔隙水压力变化规律进行分析，讨论不同的管线半径、管线壁厚和土性参数对计算结果的影响。在数值计算过程中引入黏弹性人工边界，有效地模拟散射波由有限域到无限域的传播，较为实际地反映在地震波作用下海底管线的动力响应问题。

NUMERICAL ANALYSIS OF DYNAMIC RESPONSE OF SATURATED POROUS SEABED-PIPELINE UNDER SEISMIC LOADING

Seismic-induced pore water pressure and effective stresses in the saturated porous seabed under seismic loading are the main factors that govern the overall stability of submarine pipelines. In most of the previous investigations of dynamic response of seabed，the pipeline is taken as to be rigid and generally the interaction between seabed and pipeline is overlooked. The equivalent disposal of seabed boundary also has not been taken into consideration. Therefore，the model of the seabed-pipeline interaction is established based on the Biot¢s theory of consolidation. The distribution of the seismic-induced pore water pressure along the pipeline outer surface and the dynamic response of submarine pipeline along the pipeline inner and outer surface under El Centro seismic wave are studied with ADINA. The effects of variable pipeline radius and pipeline wall thickness，variable soil modulus and soil permeability on the seismic-induced pore water pressure and internal stresses of submarine pipeline are discussed. Through numerical analysis，viscoelastic artificial boundary is taken into account to simulate the transmission of seismic wave from finite region to infinite region effectively. It actually shows the validity and accuracy of dynamic response of submarine pipeline under seismic loading.