Seismic evaluation of buried gas pipelines based on the fault slip tendency in South Korea

As numerous earthquakes occur worldwide, securing the seismic performance of infrastructure is important because the damage to buried gas pipelines during an earthquake can cause significant secondary damage. Buried gas pipelines are subject to damage owing to permanent ground movements, one of which is faulting. In this study, the expected displacement of faults caused by earthquakes is predicted by introducing the concept of slip tendency. Using approximately 14,000 fault segments obtained from fault surveys, we calculated the slip tendency based on the Korean Stereonet by region. Thus, the maximum displacement by region that could be triggered by fault reactivation was calculated. A finite-element model of a pipeline passing through a fault zone was developed by varying the actual pipeline used in Korea and various types of geotechnical information. Using this model, a structural analysis of the pipe during fault displacement was performed, and structural integrity evaluation results were derived. The strain value increased as the angle between the pipe and the fault plane increased and as the dense ground and compression-dominated movement increased, confirming this with an application example. Finally, a process capable of evaluating all regions of Korea was established using the displacement values of the predicted fault occurrence by region based on the slip tendency.