Influence on Dynamic Fault Displacement on the Behavior of Buried HDPE Pipeline Crossing Faults

Surface deformation from fault displacement threatens buried pipelines crossing fault zones. Previous studies often idealized fault displacement as a quasi-static load, neglecting dynamic rupture effects. This study investigates the dynamic fault displacement effects on buried High-Density Polyethylene (HDPE) pipelines, specifically for the case where the pipeline is perpendicular to the fault trace. A finite element model incorporating a visco-elastic artificial boundary was established and validated against shaking table tests. Dynamic fault dislocation was simulated via an equivalent load input method. Results show a strong correlation between the displacement pulse period and fault displacement magnitude. As displacement increases, the pipeline enters a plastic state, causing significant cross-sectional deformation and amplifying dynamic effects. Under combined short pulse periods and large dislocations, localized deformation is exacerbated by high-strain-rate material embrittlement and concentrated energy dissipation, impairing safety. Transient peak displacements during dynamic dislocation significantly increase plastic strain. Increasing pipeline wall thickness enhances resistance to dynamic pulses. Compared to soft clay, hard clay sites provide stronger constraints, amplifying the pulse period's influence. Sandy soil sites demonstrate superior resistance to the dynamic effects of fault displacement. The dip angle of the reverse fault has a significant influence on the pipeline's response under dynamic fault displacement loading.