Numerical modeling of the interaction of pressurized large diameter gas buried pipelines with normal fault ruptures

Abstract

There is a growing attention towards the seismic response of large diameter pipelines, owing to the potential adverse impact on economy and civilized life of a structural collapse under earthquake effects, such as strong ground shaking, and other earthquake related effects such as fault rupture, landsliding and liquefaction. The intersection of a fault rupture with a pipeline is of special concern, because the safety verification is affected by significant uncertainties in the loading condition, related to the unknown exact location where the fault offset may occur, the unknown amount of the offset itself, as well as the intersection angle of the fault rupture with the pipe axis. Besides, the inherent analytical/numerical complexity of the problem may require 3D finite element models with non-linear constitutive laws and large deformations.In this paper a summary is presented of a comprehensive set of 3D numerical simulations of the interaction of a large diameter gas pipeline with a normal fault rupture, with the main objectives of: 1) throwing light on the pipeline performance under increasing levels of fault offset, including cross-sectional buckling and ovalization; 2) providing a parametric set of results, including the variability of the fault-pipe intersection angles, of the mechanical properties of the pipe-soil interface, as well as of the operating conditions, in terms of internal gas pressure and temperature variations.