Numerical Solutions And Finite Element Simulation For Landslide Impact On Submarine Pipelines

Landslides are common seabed geological disasters.It can cause the pipeline deforming or even breaking,which leads to huge economic losses and environmental pollution.This paper aims to study impact of landslides on submarine pipelines.Improved boundary conditions are proposed to solve the problems of the discontinuous bending moment and matrix singularity in elastic stage,using the relationship between the bending moment and the displacement.The undetermined coefficients in the displacement function can be directly derived from the new boundary equations,without the matrix singular problem.It greatly improves the applicability of the method.The second-order central difference method is used when the pipeline is in elastoplastic stage.In this situation,the pipeline is designed based on the strain criterion.Converting the governing equation into a differential equation of bending moments can simplify the solution process.Improve and optimize the algorithm by analyzing various factors that affect the operation of the program to improve the computational efficiency and intelligence of the program.Later,a new method to calculate the axial force is proposed to realize the analytical solution process of variable axial force.Finite element software ABAQUS is used to establish a three-dimensional model of pipe-soil interaction to solve this problem.Contact modeling is used and the large deformation and nonlinearity of the pipe is considered.The finite element calculation results can be mutually verified with the analytical solutions.Finally,the rationality of the assumption of neglecting axial soil resistance proposed by the model is verified.Finally,this paper discusses the influence of various parameters.Only the landslide force and wall thickness can significantly affect the maximum total stress of the pipeline.The increase in landslide width,axial soil resistance and wall thickness results in a reduction in bending stress.An increase in lateral soil resistance,pipe diameter and wall thickness results in a reduction in axial stress.