Pipelines Subjected to Fault Movement in Dry and Unsaturated Soils

Abstract

Because pipelines traverse large geographical areas, they frequently must cross active faults when constructed in locations vulnerable to earthquakes. In this study, the authors performed three-dimensional (3D) finite-element analyses to investigate the behavior of buried pipe subject to strike-slip fault movement in dry sand and, more realistically, in partially saturated sand. The performance of the finite-element model was first validated by comparing the computed results with the data from the full-scale experiments at Cornell University. The analysis was then extended by varying the initial conditions of the sand (e.g., sand type, density, moisture content), pipe material, pipe burial depth, and pipeline–fault-rupture inclination to assess the effect of these parameters on the soil loads applied to the pipe and the corresponding deformations. On the basis of the simulation results, the authors propose a soil–structure interaction mechanism for pipelines crossing active faults. The authors also propose design recommendations for the mitigation of ground-deformation effects at buried pipeline crossings of strike-slip faults.