Effect of particle composition and consolidation degree on the wave-induced liquefaction of soil beds

The wave-induced liquefaction of seabed is responsible for causing damage to marine structures. Particle composition and consolidation degree are the key factors affecting the pore water pressure response and liquefaction behavior of the seabed under wave action. The present study conducted wave flume experiments on silt and silty fine sand beds with varying particle compositions. Furthermore, a comprehensive analysis of the differences and underlying reasons for liquefaction behavior in two different types of soil was conducted from both macroscopic and microscopic perspectives. The experimental results indicate that the silt bed necessitates a lower wave load intensity to attain the liquefaction state in comparison to the silty fine sand bed. Additionally, the duration and development depth of liquefaction are greater in the silt bed. The dissimilarity in liquefaction behavior between the two types of soil can be attributed to the variation in their permeability and plastic deformation capacity. The permeability coefficient and compression modulus of silt are lower than those of silty fine sand. Consequently, silt is more prone to the accumulation of pore pressure and subsequent liquefaction under external loading. Prior research has demonstrated that silt beds with varying consolidation degrees exhibit distinct initial failure modes. Specifically, a dense bed undergoes shear failure, whereas a loose bed experiences initial liquefaction failure. This study utilized discrete element simulation to examine the microscopic mechanisms that underlie this phenomenon.