DYNAMIC RESPONSE OF POROUS SEABED-PIPELINE INTERACTION SYSTEMS UNDER WAVE-INDUCED LOADING

摘要

The evaluation of wave-induced pore pressure and effective stresses has been recognized by coastal geotechnical engineers as an important factor in the design of submarine pipelines.In most previous investigations for the seabed-pipe interaction, the effect of pipeline on dynamic response of seabed has been usually overlooked and no-slip condition is mainly assumed at the interface between pipeline and seabed soils. The effect of full interaction between seabed and pipeline has not been taken account in analyses of stresses and deformations of the seabed and submarine pipeline. In fact, the mechanism of seabedpipeline interaction and its effect on stresses in the seabed and internal stresses within the pipeline has not been well understood. In this paper, the governing equations of the seabed and pipeline are formulated respectively based on the Biot's theory of dynamic consolidation of two phase media and principle of elastic dynamics. And numerical formulations based on FEM are established. In the proposed computational model and numerical procedure, effects of soil-pipeline contact are considered. For a given test case,numerical results are compared with experimental data available to illustrate the validity of the proposed method. Based on the computed results, it is found that the soil-pipeline interaction plays an important role in stresses of the seabed and pipeline and imposes little effect on pore water pressure of seabed. The maximum difference of σpx/p0 can reach 35 times of p0.