Numerical Simulations of Wave-Induced Soil Erosion in Silty Sand Seabeds

Abstract

Silty sand is a kind of typical marine sediment that is widely distributed in the offshore areas of East China. It has been found that under continuous actions of wave pressure, a mass of fine particles will gradually rise up to the surface of silty sand seabeds, i.e., the phenomenon called wave-induced soil erosion. This is thought to be due to the seepage flow caused by the pore-pressure accumulation within the seabed. In this paper, a kind of three-phase soil model (soil skeleton, pore fluid, and fluidized soil particles) is established to simulate the process of wave-induced soil erosion. In the simulations, the analytical solution for wave-induced pore-pressure accumulation was used, and Darcy flow law, mass conservation, and generation equations were coupled. Then, the time characteristics of wave-induced soil erosion in the seabed were studied, especially for the effects of wave height, wave period, and critical concentration of fluidized particles. It can be concluded that the most significant soil erosion under wave actions appears at the shallow seabed. With the increases of wave height and critical concentration of fluidized particles, the soil erosion rate and erosion degree increase obviously, and there exists a particular wave period that will lead to the most severe and the fastest rate of soil erosion in the seabed.

An Approach to Assess the Stability of Unsaturated Multilayered Coastal-Embankment Slope during Rainfall Infiltration

“…As shown in Figure 8, the critical slip surfaces predicted by both models become gradually deeper and their associated minimum safety factors progressively decrease with the increase of φ b . This is because of the amplification of φ b which significantly increases the total cohesion (shown in Equations (3)(4)(5)(6)(7)(8), and enhances the shear strength (Equation (2)), which in turn improves the safety factor. Moreover, both the critical slip surfaces (marked by the solid line) and the associated safety factor always agree well with those (marked by other line type) predicted by Zhang et al [50].…”

“…As one of the effective defensing coastal structures, embankment slope or breakwater is widely used to protect ashore human life and property from severe environment (storm, rainfall, long-term wave loading, etc.). Therefore, the instability of the embankment slope has attracted more and more attention in coastal engineering with the failure modes of scour [1][2][3][4] and shear failure [5][6][7][8]. Moreover, most of the above literature has mainly focused on wave-induced seabed instability, in which the soil was considered as saturated material [4,6,[9][10][11][12][13].…”

Coastal Geohazard and Offshore Geotechnics

“…In this Special Issue, eighteen papers were published, covering three main themes: (1) mechanism of fluid-seabed interactions and its associate seabed instability under dynamic loading [1][2][3][4][5];…”

Scour Effects on the Lateral Behavior of a Large-Diameter Monopile in Soft Clay: Role of Stress History

“…Scour is a process of soil erosion and can often occur around the foundations of offshore structures [1][2][3][4][5]. Currently, monopiles are the most widely employed foundation for offshore wind turbines, and its slenderness ratio of embedded pile length to pile diameter (L/D) are relatively small (typically in the range of [4][5][6][7][8].…”