Research On Dynamic Response And Buckling Failure Of Submarine Pipeline Under Seismic

In this paper,the damage of oil and gas transportation system under the action of seismic load was taken as the research direction,and two key problems of seismic response and local buckling of pipeline crossing fault were studied.The response and buckling failure mechanism of submarine pipeline under the combined action of water pressure and dynamic load were studied by numerical simulation and experimental verification.In the aspect of test,a series of combined lateral vibration and water pressure loading tests were carried out on the full-scale pipe fittings based on the lateral vibration device of full-scale deep-water pressure test chamber.In the aspect of numerical simulation,based on ABAQUS finite element software,the buckling failure model of suspended span pipeline under the combined action of lateral vibration and water pressure wasp established by secondary development to simulate the inertial effect of external fluid on the pipeline.The test results were basically consistent with the numerical simulation model.The acceleration time history curve of the two models at the same position and the collapse pressure of the pipeline are highly consistent,which verifies the effectiveness of the numerical simulation model in dynamic analysis and the accuracy of the second development of the finite element.At present,there were few research results on the combined effect of seismic load and external water pressure on the submarine suspension pipeline.Based on the above lateral vibration hydraulic joint loading model,this paper further simulated the response of pipeline under the combined action of seismic load and external hydraulic pressure.The real stress state of pipeline under earthquake was simulated,and the inertial effect of fluid on pipeline in dynamic analysis was effectively simulated by the method of additional mass element.Finally,the influence of seismic load on the response of the pipeline under different conditions is determined by the method of incremental time history analysis.When the earthquake causes permanent deformation of the fault,the buried pipeline crossing the fault will generally have large plastic deformation.In order to determine whether the deformed pipeline can work normally,it is necessary to predict its strain according to the actual working conditions.Based on ABAQUS,a threedimensional solid simulation model of pipeline and strike slip fault was established,and the local buckling failure mode and strain distribution of pipeline were obtained.A number of sensitive factors including soil properties were discussed,and the influence of different sensitive factors on the strength of bottom pipeline was analyzed qualitatively.On the basis of numerical simulation data,the BP neural network optimized by genetic algorithm was used to realize the accurate prediction of pipeline strength by MATLAB software.