Mitigating strike-slip fault rupture damage in buried steel pipelines with geogrid reinforcement

This study investigates the effectiveness of geogrid reinforcement in mitigating seismic damage to buried continuous steel pipelines subjected to strike-slip fault rupture. Single and double geogrid layers installed in the surrounding soil aimed to redistribute the concentrated stresses and strains along the pipe, thereby reducing localized failure. Three-dimensional numerical models were developed to explicitly represent the steel pipe, soil deposit, and geogrid layers, capturing their complex interactions. Fault rupture was applied incrementally up to 4 m, and reinforced pipelines were evaluated against unreinforced cases using strain-based criteria, including maximum tensile strain, local buckling, ovalization, and geogrid rupture. The influence of design parameters, pipeline orientation, and wall thickness was also assessed. Geogrid reinforcement markedly enhanced seismic performance, delaying tensile, buckling, and distortion failures. Double-layer reinforcement increased the critical fault displacement by more than 96% and produced more distributed deformation than unreinforced pipelines. Parametric optimization further enhanced performance: increasing the fault crossing angle from 10° to 30° and reducing the D/t ratio from 144 to 58 improved resilience by approximately 30% and 54%, respectively. Obtained numerical results demonstrate that geogrid reinforcement is an effective and practical strategy for improving the seismic resilience of buried steel pipelines crossing active faults.