Vulnerability of Buried Energy Pipelines Subject to Earthquake-Triggered Transverse Landslides in Permafrost Thawing Slopes

Abstract

Current regional seismic loss estimation models, for example, the United States Federal Emergency Management Agency’s (FEMA) Hazus, typically employ empirical functions for damage assessment of buried pipelines subjected to permanent ground deformation (PGD). These functions are based on a limited number of damage observations to pipelines during past strong earthquakes. They represent the repair rate per unit length in a brittle or ductile pipe segment under average structural and geotechnical conditions and ground failure phenomena. This study aims to propose an analytical method for assessment of vulnerability of ductile energy pipelines traversing permafrost regions and subject to active layer detachment (ALD) landslide hazard. Canadian ALD morphological statistics combined with the probability of pipeline exposure to transverse ALD-caused PGD and the extent of the potential PGD are used as input. A computer program is developed in order to analyze the structural behavior of pipelines and evaluate their vulnerability considering three damage mechanisms: tensile rupture, local buckling, and premature cross-sectional failure. The vulnerability functions associated with PGD, expressed in terms of repair rate, are obtained by applying Monte Carlo simulation to the structural analysis results. The novel vulnerability functions developed herein are specific to permafrost regions and can be incorporated in the Hazus-type platforms for regional seismic risk assessment.