Coupling Model for Wave-Induced Oscillatory and Residual Response Around Buried Submarine Pipeline

Wave-induced response and liquefaction may threaten the stability of the seabed in the vicinity of submarine pipelines. Previous studies have mostly focused on the oscillatory or residual liquefaction of the seabed around pipeline, which neglects the coupling process of seabed response. Actually, in the real environment, both the oscillatory and residual responses occur simultaneously which are coupled with each other within the seabed. In this study, one coupling model for the seabed response around pipelines is developed. Based on the fully dynamic (FD) poroelastic soil theory, the oscillatory and residual responses of the seabed can be simultaneously simulated by taking the accelerations of fluid and soil skeleton into consideration. Model validations are conducted by comparing the pore pressure variation between the present model and an existing wave flume test. By model application, the coupling seabed response and development of the liquefaction zone around the buried pipeline are investigated. It is indicated that pore pressure accumulates most significantly at both sides of the pipeline; the presence of the pipeline increases the liquefaction depth nearby slightly.