ABSTRACT Duan, L.; Xing, L.; Wang, D.; Fan, M., and Wang, P., . Numerical investigation of wave-induced uplift force exerted onto a shallowly buried pipeline using a two-dimensional fully coupled model for wave-seabed-structure interaction. In this paper, a novel two-dimensional numerical model for wave-seabed-pipeline interaction is proposed to investigate the wave-induced uplift force exerted onto a shallowly buried pipeline. Unlike previous models, the present model is fully coupled, and the effects of fluid shear stress at the seabed surface on the soil dynamic response are considered. In this study, the Reynolds-averaged Navier-Stokes equation was applied to simulate flow motions, and the level set method was used to track the free water surface. Meanwhile, Biot's poroelastic equation ( u-p mode) was taken to govern the wave-induced oscillatory response of the seabed, and the pipeline was treated as elastic. After validation using data from laboratory experiments in the literature, the novel model was first employed to investigate the distribution of the wave-induced transient seabed response around the shallowly buried pipeline. Then, the effects of the wave parameters, the soil properties, and the pipeline diameter and burial depth on the wave-induced maximum uplift force exerted onto the structure were systematically examined in detail. Finally, wave-induced maximum uplift of the shallowly buried pipeline was predicted based on the numerical results, which may provide some references for engineering practice. Numerical results confirmed that both the nonlinear pipeline-seabed contacts and the fluid shear stress at the seabed surface can greatly affect the soil dynamic response, which should be considered in determining the wave-induced uplift force exerted onto a shallowly buried pipeline.

ABSTRACT Wang, C.; Jiang, Z.; Wang, D.; Feng, D., and Duan, L., 2020. Effects of the porous medium seabed on the wave load acting on the single pile. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research , Special Issue No. 111, pp. 192–197. Coconut Creek (Florida), ISSN 0749-0208. The characteristics of the seabed greatly affect the interaction between waves and the single-pile foundation structure. It is normal to simplify the porous medium seabed into a rigid, impermeable solid seabed, which ignores the effect of the porous medium seabed on wave energy. This study investigated the effects of the seabed characteristics of porous media on the wave load of the single pile based on the wave-flume test and the three-dimensional numerical model. Five seabed wave-flume tests and the common ocean conditions wave-soil-structure interaction numerical analysis model were designed to verify the accuracy of the numerical model and to analyze the effect of porous media seabed characteristics on wave loads. Results show that the wave load on the single pile depends on the seabed porosity, the average seabed-particle diameter, and the seabed thickness. The seabed-particle diameter has the most significant influence on the wave load of the single pile. The formula for the relationship between the wave load of the single pile and the seabed-particle diameter is derived under different wave conditions.