A 3-D numerical study of the random wave-induced response in a spatially heterogenous seabed

Abstract

Abstract The seabed failure poses a significant threat to the stability of marine structures. The actual wave-induced dynamic response in a porous seabed is a complex issue due to the randomness in hydrodynamic pressure and the spatial variability in soil properties. A probabilistic framework was proposed based on a 3-D stochastic finite element model for the investigation of the random wave-induced responses in a spatially heterogenous seabed. The framework integrates the generation of random waves as well as the random soil and the finite element analysis of poroelasticity via a Livelink code. A decomposed Karhunen-Loeve expansion method was proposed, making the generation of multi-dimensional random fields with high resolution and large scale possible. Contrastive analyses of different scenarios were conducted to study the effects of the randomness of wave pressure and the spatial variability of the soil shear modulus on the seabed response. Monte Carlo simulations were used for the statistics of seabed response, and then the effects of the correlation length of random fields on the liquefaction depth were investigated. The results of the analysis highlighted the significant impacts of the randomness of ocean waves and the spatial variability in soil properties, which were often ignored in previous studies.