Numerical simulation of strength failure of buried polyethylene pipe under foundation settlement

• The influence of strain rate on properties of polyethylene is considered.
• Changes of piping stress during the foundation settlement process are studied.
• The transition section is an important region, and shall be concerned.
• The methodology provide a good reference for buried polyethylene pipe analysis.

Polyethylene (PE) pipes have a great ability to resist deformation, which is one of the important reasons that PE pipes are used more and more widely in urban gas transportation systems. In this paper, a numerical simulation was conducted in ABAQUS, for the most commonly used PE pipe of DN110-SDR11, under the action of foundation settlement. The situation that PE pipe is perpendicular to settlement section was considered. The variation of piping stress vs settlement displacement was analyzed, and influence of length of transition section on pipe yielding was discussed. It was found that the maximum Mises stress of PE pipe increases with the increment of settlement displacement, but the location is changing, and the dangerous section occurs at the junction of transition section and subsidence area or the junction of transition section and non-subsidence area. Pipe yielding was taken as the failure threshold, and the maximum settlement displacement under which PE pipe serves safely was analyzed. With increasing length of transition section, the settlement displacement for pipe yielding increases, that is PE pipe with longer length of transition section is safer than those with shorter one under the same settlement displacement.

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