Effects of the Soil Property Distribution Gradient on the Wave-Induced Response of a Non-Homogeneous Seabed

Abstract

The seabed is usually non-homogeneous in the real marine environment, and its response to the dynamic wave loading is of great concern to coastal engineers. Previous studies on the simulation of a non-homogeneous seabed response have mostly adopted a vertically layered seabed, in which homogeneous soil properties are assumed in the governing equations for one specified layer. This neglects the distribution gradient terms of soil property, thus leading to an inaccurate evaluation of the dynamic response of a non-homogeneous seabed. In this study, a numerical model for a wave-induced 3D non-homogeneous seabed response is developed, and the effects of the soil property distribution gradient on the wave-induced response of a non-homogeneous seabed are numerically investigated. The numerical model is validated, and the results of the present simulation agree well with those of previous studies. The validated model is applied to simulate an ideal two-dimensional (2D) vertical non-homogeneous seabed. The model is further applied to model the practical wave-induced dynamic response of a three-dimensional (3D) non-homogeneous seabed around a mono-pile. The difference in pore pressure and soil effective stresses due to the soil distribution gradient is investigated. The effects of the soil distribution gradient on liquefaction are also examined. Results of this numerical study indicate that (1) pore pressure decreases while soil effective stresses increase (the maximum difference of the effective stresses can reach 68.9 % p 0 ) with a non-homogeneous seabed if the distribution gradient terms of soil properties are neglected; (2) the effect of the soil property distribution gradient terms on the pore pressure becomes more significant at the upper seabed, while this effect on the soil effective stresses is enhanced at the lower seabed; (3) the effect of the soil distribution gradient on the seabed response is greatly affected by the wave reflection and diffraction around the pile foundation; and (4) the soil distribution gradient terms can be neglected in the evaluation of seabed liquefaction depth in engineering practice.

Wave-induced residual response and liquefaction of a nonhomogeneous layered seabed

“…The shear stress of the soil under the action of waves can be obtained by solving the oscillatory response of the seabed, which is adopted as a driving force for the seabed residual response (Seed and Rahman, 1978). More details about the oscillatory model which involves the stress-strain relation, discretization scheme et al, interested readers can refer to the authors' previous publication of Sui et al (2019a).…”

“…This leads to a pressure discrepancy between the inner bed and the bed surface, i.e., excess pore pressure, which is the most important factor in the onset of liquefaction (Jeng, 2012). Numerous previous studies have focused on momentary liquefaction, including theoretical research (Yamamoto et al, 1978), experimental studies (Qi et al, 2019), and numerical simulations (Jeng et al, 2013;Zhang et al, 2016;Li et al, 2018;Sui et al, 2019a;Liu et al, 2023b). Momentary liquefaction mainly occurs in sandy seabeds with relatively high permeability and compressive resistance.…”

Micro-mechanical analysis of caisson foundation in sand using DEM: Particle shape effect

“…The seabed soils are usually non-homogeneous and subjected to natural spatial variation in terms of soil behavior and particle micro-structure (Peng et al, 2017;Sui et al, 2019).…”

Features of Earthquake-Induced Seabed Liquefaction and Mitigation Strategies of Novel Marine Structures

“…For instance, Jia and Ye carried out systematic wave flume experiments and numerical simulation works respectively, which well explained the hydrodynamic behaviors (liquefaction and re-suspension) of marine deposits under the sea wave loads [13,14]. Sui et al considered distribution gradient terms of soil properties and analyzed liquefaction of an inhomogeneous seabed caused by waves [15]. Huang et al comprehensively reviewed the mechanisms of wave-induced liquefaction and relevant remedial measures [16].…”