Numerical investigation of pore pressure effect on blast-induced pipeline-seabed interaction

It is well-known that the pore water pressure plays an important role in the design of submerged structures since interaction of pore water and soil particles significantly affects surrounding soil behavior. However, the role of pore water within saturated soil was commonly neglected when estimating the blast-induced soil response. A pipeline-seabed interaction (PSI) model is established to simulate blast response of pipelines with consideration of pore water effect. The u-p approximation is incorporated into finite element method (FEM) to study dynamic response of pipelines buried in fully saturated soil subjected to underwater explosion. The Arbitrary Lagrangian-Eulerian (ALE)-Lagrangian algorithm is utilized to solve large deformation in the vicinity of underwater explosion. Test data from previous literature is adopted to validate the proposed model. Then, comparative analysis is carried out between the proposed model and the conventional model that excludes pore pressure. Numerical results from the proposed model are found to be distinctive from those obtained from the conventional model. Blast responses of the pipelines and soil are underestimated generally by the conventional approach. This contrastive analysis emphasizes pore pressure effect in engineering design of submerged pipelines.