Structural performance of buried pipeline undergoing strike-slip fault rupture in 3D using a non-linear sand model

Abstract

Nonlinear structural response of buried continuous pipeline undergoing strike-slip fault rupture, i.e., where soil masses get displaced in the horizontal plane along a fault line, is studied in a detailed manner. A detailed analysis technique employing ABAQUS/Standard with implicit formulation to study the behavior of buried continuous pipelines crossing fault movements is proposed and established with suitable validations. A three-dimensional nonlinear finite element (FE) model including both material and geometric nonlinearities is used for this study. Firstly, a non-linear sand constitutive model is adopted and implemented in commercial FE package ABAQUS. The adopted material model is validated with available experimental tri-axial test results. This material model is thereafter suitably calibrated to develop a FE model of buried pipeline undergoing fault rupture for a specific large-scale experimental test. The study identified important soil strength parameters from direct shear soil tests conducted for the large-scale test program and converted them suitably with respect to the adopted sand constitutive model. The FE model is then validated against full-scale experimental results. It is observed that the developed FE model yields highly accurate results in comparison to available numerical results for this experiment. Analysis results indicated that, consideration of sand non-linear mobilized shear strength appropriately in numerical modelling may result in significantly improved prediction of generated pipeline strains with increasing fault displacements.