Study On Stability Of Sea-bed Around Submarine Pipeline Under Wave Load

With the rapid development of marine engineering nowadays,marine pipelines have been widely used in various transportation projects of marine resources such as oil,natural gas and other important marine resources,which are transmitted to land through submarine pipelines.In practical situation,therefore,the safety of pipelines in transition must be taken into consideration on account of the instability of submarine pipelines in this process caused by the complexity of the marine environment,the composite effect of various loads and the particularity of marine environment compared to land.In the practice of practical application in the past few decades,a considerable number of accidents have been caused by the failure of submarine pipelines in complex environments,resulting in safety accidents,so it is of vital importance to analyze the stability of submarine pipelines in marine environment.In previous studies,the contents of the seabed,wave load,scour and liquefaction have been perfected and enriched,thus this paper would summarize the previous researches to build a numerical model of wave-seabed-pipeline interactions,and further validate the model with the existing articles’ analytic solution and experimental data at the same time.In this paper,a two-dimensional numerical model of the interactions between wave-seabed and submarine pipelines is proposed according to the momentum source function method,which can be replaced by the wave model and the numerical information of the seabed model at the interface,so as to realize the interactions between the two-dimensional model and to ensure the coupling of the model.By calculating the pore water pressure in the wave model to obtain the extra pore water pressure,this paper discusses the stability of the seabed of the all-buried submarine pipeline under different wave characteristics and soil characteristics,and calculates the displacement response in the model with different wave heights,different wave periods,different soil permeability and seabed saturation by software numerical calculation,also strain response and pore pressure cloudmap.Through the comparison and analysis of these three aspects,so as to know that all buried submarine pipelines under different characteristics of the seabed stability around the pipeline.In addition,there is an influence of embedding depth on the stability of the seabed around semi-buried submarine pipelines,and three different embedding depths are also listed to calculate the model.The increase of wave height and wave period will lead to the increase of sea-bed liquefaction depth,and the increasing depth of embedding will reduce the liquefaction depth of the seabed around the semi-buried pipelines,and there is an existence of critical embedding depth prevent liquefaction from occurring.