Local Dent Behavior of Directional Crossing Pipeline Caused by the Boulder in Stratum

Abstract

Dent of crossing pipeline caused by the boulder in the stratum may result in pipeline premature failure. Dent process of the crossing pipeline was investigated. Effects of boulder load, pipeline pressure and diameter-to-thickness ratio on the dent behavior were discussed. The results show that dent deformation process of non-pressure pipeline consists of five phases, while the process of pressure pipeline consists of eight phases. When the boulder load increases, plastic deformation increases and a dent with ship shape appears on the pipeline. Dent rate, dent depth and length increase when the diameter-to-thickness ratio increases. With the increasing internal pressure, dent rate of the pipeline decreases, but rebound rate increases. Axial length of the dent for pressure pipeline is smaller than non-pressure pipeline.