Numerical Simulation of Transverse Deformations of Buried Pipelines Due to Slope Instability

Document Type : Research Article

Authors

1 civil engineering department, Ferdowsi University of Mashhad

2 Civil Eng. Department, Faculty of engineering, Ferdowsi University of Mashhad

Abstract

Buried pipelines are used to transport water, liquid fuel, gas, oil, etc. and they must remain in service in all circumstances such as permanent transverse ground deformation caused by slope instability. In the literature, modeling of soil-pipe interaction is carried out mostly by using soil-equivalent spring, and instead, continuum modeling is rarely used. In the modeling problem, the main question is the estimation accuracy of the pipe deformation. In this paper, it is tried to study the deformational behavior of a pipe installed over an unstable slope. In this study, the simulation was performed by using a continuum approach by using FLAC 3D software, which is based on finite difference method. The effect of parameters such as pipe diameter and thickness, width of the slope, soil cohesion and soil internal friction angle on pipe deformation were investigated. The simulation results indicate that the maximum displacement of the transverse ground and pipe occurs in the center of the area and reaches zero in the sides. The forces/stresses in the pipe are symmetric to the center of the model and reach a maximum value in the center. Furthermore, as the ground movement increases, the pipe maximum strain increases linearly while it remains constant anymore at larger ground deformation which is called critical deformation. By comparison of the numerical results with those of analytical methods for a large-scale physical test, it can be said that the numerical model can more precisely predict the pipe deformation and forces/bending moments. Parametric studies show that some solutions such as an increase in the diameter of the pipe, increase in thickness of the pipe wall and a decrease in the slope angle can effectively reduce the displacements and forces imposed in the pipe.

Keywords

Main Subjects

References

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Amirkabir Journal of Civil Engineering
Volume 52, Issue 5
August 2020
Pages 1187-1204

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