关键词: 波浪荷载, 海床响应, 随机场, 空间变异性, 随机有限元法

Abstract: Wave-induced seabed response is a research hotspot in the field of geotechnical engineering. The wave-induced seabed liquefaction is the main reason for the instability of seabed and marine structures. In view of many uncertainties involved in the analysis of the seabed response, such as the spatial variability of sediment properties and the randomness of related loads, a probabilistic framework based on the stochastic finite element method is developed, which couples the simulation of spatially heterogeneous soil in MATLAB and the finite element analysis of poroelasticity in COMSOL through the LiveLink program. A decomposed K-L expansion method is proposed, which takes less computational time and memory space, making the generation of three-dimensional random fields with high resolution and large scale more effective. Based on the proposed probabilistic framework, the dynamic response of both the two-dimensional sloping seabed under regular waves and the three-dimensional seabed under random waves are studied. The influence of the spatial variability of the permeability coefficient K and shear modulus G of marine sediments and the randomness of wave loads on the distribution of pore water pressure and the liquefaction depth in the seabed are revealed. The study has shown that traditional deterministic analysis methods lead to unsafe engineering designs.

Key words: wave loading, seabed response, random field, spatial variability, stochastic finite element method