INVESTIGATION ON WAVE-INDUCED SEABED RESPONSE AROUND A BURIED PIPELINE CONSIDERING COUPLING EFFECT OF PORE PRESSURE ACCUMULATION AND STRESSES

The wave-induced seabed liquefaction is an important factor that causes instability of submarine pipelines buried in sediments. The accumulated excess pore water pressure may cause deeper soil liquefaction,which leads to severer influence on stability of pipelines. Therefore,many researchers pay their attention to the residual response of seabed-pipeline system under waves. This study uses the numerical model that considers the coupling effect of pore pressure accumulation and seabed stresses and simulates the seabed residual response with a buried pipeline under nonlinear progressive waves. The results are compared with those of the decoupled numerical model. The results have shown that for the case of considering the coupling effect of residual pore pressure and seabed stresses,the non-uniform distribution of residual pore pressure in the vicinity of the pipeline can cause an increase of the cyclic shear stress,which can significantly accelerate the development of residual pore pressure in the associated area and enlarge the influenced range of the pipeline. Neglecting the coupling effect of residual pore pressure and seabed stresses can underestimate the depth of liquefaction around the buried pipeline to some extent,which is conductive to the safety of pipelines.