Frequency response analysis of concrete seawall including soil-structure-seawater interaction

https://doi.org/10.1016/j.soildyn.2020.106392Get rights and content

Highlights

  • A finite element model for the seismic response of water-structure-sediment-foundation-backfill coupling system.

  • Considering the dynamic interactions among various domains.

  • Adopting the perfectly matched layer (PML) as an absorbing boundary condition.

  • Evaluating the effects of sediment thickness, water depth, foundation stiffness, and backfilled soil on the response.

Abstract

In this study, a frequency-domain finite element model is proposed to evaluate the seismic response of water-structure-sediment-foundation-backfill coupling system. It includes the seawater as a compressible fluid, seawall as viscoelastic solid, backfilled soil, sediment, and foundation as two-phase poroelastic domains with dynamic behavior described by u-p formulation of Biot’s equations. The dynamic interactions among various domains are fully considered and the PML is adopted as an absorbing boundary condition to truncate the computational domain, absorbing all out-going seismic waves. The dynamic responses in the structure, water and soil are assumed to be generated by the vertical propagating shear or compressional waves from the bedrock substrate under the foundation soil. Both the actions of horizontal and vertical seismic excitations at the bottom of foundation are respectively considered. After verifying the accuracy of PML and coupled model of soil-structure-water system, a series of parametric studies are conducted to investigate the effects of sediment thickness, water depth, foundation stiffness, foundation thickness, inclination of seawall, and properties of backfilled soil including soil permeability, shear modulus, and saturation degree, on the frequency response at the top of seawall.

Section snippets

Author contribution

Weiyun ChenZhicheng WangShaolin ChenJianjun MaYu Liang

Theoretical formulation

The problem under study is a water-structure-sediment-foundation-backfill system which is shown schematically in Fig. 1. A typical gravity seawall with top width B, height H and wall inclination θ rests on a foundation (subsoil). The wall retains a horizontal backfill at one side and a large volume of seawater at the other side, with alluvium or sediment deposited at the reservoir bottom. The depth of sediment is Hs and the depth of water on the seaward side is Hw. The foundation, sediment, and

Verification

As shown in Fig. 1, the perfectly matched layer (PML) [[27], [28], [29]] is used as an absorbing boundary condition to truncate the computational domain, absorbing all out-going waves. Before the numerical analysis, it is necessary to validate the effectiveness of the proposed PML. In subsection 3.1, the numerical examples only for the wave radiation problem are firstly presented to demonstrate the accuracy of the proposed PML. In subsection 3.2, further verification is presented for more

Numerical studies and discussions

Comprehensive analyses of various parameters of sediment, backfill, foundation, seawater and structure are presented in this section, from which the discussions are given to evaluate the main influencing factors on the seismic response of seawall. The top width of seawall B = 2 m, the wall height H = 10 m, and the wall inclination θ = 0°. The thickness of the foundation soil is assumed to be 20 m. The parameters for the two-phase porous materials at different domains in the model are given in

Conclusions

This paper establishes a frequency-domain numerical model to evaluate the seismic response of a water-structure-sediment-foundation-backfill coupling system with full consideration of interactions among different domains. The u-p formulation of Biot theory is adopted in modeling the fluid-saturated sediment, backfill, and foundation soil. The PML is used as an absorbing boundary condition to truncate the computational domain. After verifying the effectiveness of PML, the proposed model is used

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

The authors gratefully acknowledge the financial support provided by the National Natural Science Foundation of China (Nos. 41877243and 41502285). Special thanks for professor Matteo Mori at Pisa University for his guidance on the numerical model.

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