Research on Anti-Corrosion and Coating Technology of Outer Pipes of Submarine Pipelines Shallow Sea by Physical Testing

In this paper, by discussing the characteristics of the beach and shallow sea marine environment, combining with engineering design and application, studying the anti-corrosion coating and coating technology of the outer pipe of the pipeline, and analyzing the design of the concrete counterweight layer of the submarine pipeline. According to the submarine pipeline of the environment, structural characteristics, construction methods, etc, the reasons for the damage of the external protective coating under certain conditions are explained, so as to select the external protective coating more reasonably, and provide data for the anti-corrosion and coating selection of the marine pipeline.

Numerical Study of Local Scour around a Submarine Pipeline with a Spoiler Using a Symmetry Boundary Condition

A two-dimensional numerical model for solving the Navier–Stokes equations was developed to investigate the local scour around a submarine pipeline with a spoiler. Both the suspended load and the bed load were considered in the present numerical model. The focus of the present study is to investigate the effects of the spoiler length on the hydrodynamic forces on the pipeline and the spoiler as well as the local scour around the submarine pipeline. The corresponding numerical results show that the mean drag coefficients of the pipeline and the spoiler increase with the increase of the spoiler length. As for the mean lift coefficient, a general decreasing trend with the increasing spoiler length is observed for the pipeline. However, the mean lift coefficient of the spoiler first increases and then decreases with the increasing spoiler length. In addition, it is found that a larger spoiler length leads to a deeper scour depth, and an empirical equation was proposed for predicting the non-dimensional scour depth of submarine pipelines with non-dimensional spoiler length based on the numerical results.

Numerical Analysis of the Design of a Subsea Gas Pipe Route Passing the Thrust Fault Using the Finite Element Method

In submarine pipeline route planning, there is a possibility that the pipeline route will pass through a potential geohazard in the form of an active subduction zone. The planned pipeline route in this study is located in the Arafura Sea, which cross path through a subduction zone system that has a thrust fault mechanism. To analyse the structural response of the pipe passing through the thrust fault, a numerical analysis using the finite element method is being used. Numerical modelling will accommodate the interaction of nonlinear behaviour between an API 5L X70 steel pipe and a cohesive clay soil. Then the pipe section in the fault area will be examined in detail with a parametric study of the variation in the angle of the pipe passing through the fault line and the impact of various earthquake magnitudes. The results of the numerical analysis show that the maximum von mises stress and maximum strain values will have a greater value for a larger pipe angle and a greater earthquake magnitude. The axial strain along the pipe will be significantly increased at the fault line and has a greater value for the pipe on the hanging wall than the pipe on the footwall. It can be concluded that the optimum route for the submarine pipeline passing through the thrust fault should be kept as small/short as possible against the fault line. The results of this analysis are expected to provide an overview of the behaviour of submarine pipes that pass through the thrust fault so that the pipe route designed can be optimal by considering safety, integrity, and efficiency.

Submarine pipeline stability under currents and waves action

Pipelines are widely used in recent decades because their eco-friendliness, safety and profitability of transportation. Their length can be more than hundreds and thousands of kilometers. Submarine pipelines got wide distribution. Their constructing must comply with regulatory documents. But even it cant guarantee no problems during operation. This study contains review of the different research, connected with floating of a submarine pipeline problem. Information about conducted research and their conclusions is summarized in this paper. Direction for the future investigations is shown. Submarine pipelines are subjected to vertical movement (floating). Pipeline ballasting method is used to avoid this situation. Ballasting by loading bags is considered in this article. This study contains review of the different research, connected with floating of a submarine pipeline problem. Calculations required for the correct selection of the loading bags weight are performed, possible reasons for floating are described. This article will be useful for submarine pipeline designers.