波浪作用下孔隙海床-管线动力相互作用分析

Numerical analysis of dynamic response of saturated porous seabed-pipeline interaction under wave loading

波浪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之间的相互作用效应,同时也没有考虑土体和管线加速度对海床动力响应的惯性影响,从而无法确定由此所引起的管线内应力。为此考虑管线的柔性,分别采用饱和孔隙介质的Biot动力固结理论和弹性动力学理论列出了海床与管线的控制方程,进而采用摩擦接触理论考虑海床与管线之间的相互作用效应,基于有限元方法建立了海床-管线相互作用的计算模型及其数值算法。通过变动参数对比计算讨论了管线几何尺寸、海床土性参数对波浪所引起的管线周围海床孔隙水压力和管线内应力的影响。

Wave-induced pore pressure and effective stresses in the saturated porous seabed under wave loading are the main factors that govern the overall stability of submarine pipelines. In most of the previous investigations for response of seabed, the pipeline is taken as rigid and generally the interaction between seabed and pipeline is overlcoked. The inertia effects of both seaflcor softs and pipeline accelerations on dynamic response of seabed also have not heen taken inte consideration. The effect of seabed-pipeline interaction on internal stresses within the pipeline has not been well understood. In this paper, the governing equations of the seabed and pipeline are formulated based on the Biot＇ s theory of consolidation and elastic dynamics theory respectively. The seabed-pipeline interaccdon problem is investigated by using the friction contact theory and the finite eleements method. Based on the numerical model presented, the effects of pipeline geometry and soil characteristics on waveinduced pore pressure and internal stresses of the pipeline are discussed.