Kinematic distress of pipelines subjected to secondary seismic fault rupture

Abstract Fault rupture is a complex phenomenon and substantial secondary ruptures have been observed. Such ruptures may cause damage to pipelines laying in the vicinity of main faults without intersecting them. The current study investigates numerically the response of buried steel pipelines crossing secondary faults, following a decoupled approach. Initially, a 3D numerical model is used to calculate soil displacements, which subsequently are applied to another numerical model for the calculation of pipe distress. Sandy soil response is realistically simulated by adopting an elastoplastic Mohr-Coulomb constitutive model with isotropic strain softening. Both models are compared with experimental results for singe fault rupture. The impact of several parameters is examined, such as fault type, soil layer properties and thickness, and different pipe routes with respect to the faults. Useful conclusions are drawn regarding the applicability of the proposed numerical approach as well as the severity of pipe distress under secondary faulting.