A numerical procedure to establish a safe working pressure during excavation of a pipeline in a rock ditch

Abstract

The purpose of this work is to describe a numerical procedure that was conducted to examine the effect of internal pressure on the possibility of puncturing and rupturing a high-pressure gas pipeline due to the impact of a falling rock. The mass and the height of the falling object were fixed. The analyses were performed in two parts: first by comparing an initial potential energy of the indenter with the energy needed to dent and possibly puncture the pipeline, then by determining if the resulting puncture would result in unstable crack extension leading to pipeline rupture. Finite element analysis was used to examine various shapes of the indenting surface to assess the effect of contact geometry on the puncture resistance. For cases where puncture is predicted, the dimensions of the hole are compared to the critical pressure to cause rupture, using industry standard methodology. The overall procedure can thus be utilized to determine the critical pressure to avoid a rupture due to a falling rock. By further application of an appropriate safety factor, the safe working pressure for a pipeline excavation can be established.