Mechanical Analysis of Buried Polyethylene Pipelines under Ground Overload

Abstract

Polyethylene (PE) pipelines are widely used in natural gas transmission systems in urban areas. With the acceleration of urbanization, the scale of PE natural gas pipelines has expanded rapidly. Thus, urban gas pipeline accidents caused by ground overload are inevitable. In this paper, the mechanical behavior of PE pipeline subjected to ground overload was investigated by the finite element method. PE pipe and soil were all established into a three-dimensional finite element model by using continuous solid elements. And parametric analysis was conducted to discuss the effects of pressure parameters, pipeline parameters and soil parameters on PE pipe’s mechanical response. The numerical simulation results indicated that the main failure form of buried PE pipe subjected to ground overload is ovalization deformation. With the increase in ground load, the ovalization deformation of the pipeline increases gradually and the maximum stress point of the pipe is transferred from the top (bottom) of the pipe to the midsection of the pipe. The buried depth of pipe, the wall thickness of pipe, internal pressure and backfill type play a great role. Within a reasonable range, it will be safer if the pipe has greater wall thickness, buried depth and internal pressure. Meanwhile, the high soil’s elasticity modulus and Poisson ratio backfill type are more conducive to the safety of buried PE pipelines.