Investigating brittle damage of buried pipelines under dip-slip faulting with peridynamics

Permanent ground deformation induced by surface faulting can seriously threaten the structural integrity of buried pipelines. The failure mode of fracturing in pipe wall is somewhat difficult to be simulated by the classical finite element method. In this work, brittle damage of buried pipelines subjected to different dip-slip faults is investigated by using peridynamics, where the pipes are characterized as peridynamics shell structures and the surrounding soil is simulated as Winkler springs. Three sets of experiments are simulated using the proposed modeling strategy, and good agreements between experimental and numerical results are achieved, in terms of progressive brittle damage features (deformation and crack patterns). The first crack initiates under a certain fault displacement, and then it propagates inwardly to penetrate through the cross section on the footwall side. A new crack then occurs on the other side in a later stage. Pipeline failure is more prone to occur within the zone of three times the pipe diameter from the fault plane, showing three broken segments by the two dominant cracks eventually. Parametric study suggests that reverse faulting is more harmful to the pipeline than normal faulting. The most unfavorable dip angles for pipelines under normal and reverse faulting are 65° and 75°, respectively. The pipeline with a thicker pipe wall or a higher critical energy release rate, being buried in a smaller burial depth or a looser sand condition, shows a higher capacity to resist the dip-slip fault.