Cnoidal Wave-Induced Residual Liquefaction in Loosely Deposited Seabed under Coastal Shallow Water

2021 ◽  
Vol 11 (24) ◽  
pp. 11631
Author(s):  
Xiuwei Chai ◽  
Jingyuan Liu ◽  
Yu Zhou

This study is aimed at numerically investigating the cnoidal wave-induced dynamics characteristics and the liquefaction process in a loosely deposited seabed floor in a shallow water environment. To achieve this goal, the integrated model FSSI-CAS 2D is taken as the computational platform, and the advanced soil model Pastor–Zienkiewicz Mark III is utilized to describe the complicated mechanical behavior of loose seabed soil. The computational results show that a significant lateral spreading and vertical subsidence could be observed in the loosely deposited seabed floor due to the gradual loss of soil skeleton stiffness caused by the accumulation of pore pressure. The accumulation of pore pressure in the loose seabed is not infinite but limited by the liquefaction resistance line. The seabed soil at some locations could be reached to the full liquefaction state, becoming a type of heavy fluid with great viscosity. Residual liquefaction is a progressive process that is initiated at the upper part of the seabed floor and then enlarges downward. For waves with great height in shallow water, the depth of the liquefaction zone will be greatly overestimated if the Stokes wave theory is used. This study can enhance the understanding of the characteristics of the liquefaction process in a loosely deposited seabed under coastal shallow water and provide a reference for engineering activities.

2014 ◽  
Vol 716-717 ◽  
pp. 284-288
Author(s):  
Jian Kang Yang ◽  
Hua Huang ◽  
Lin Guo ◽  
Jing Rong Lin ◽  
Qing Yong Zhu ◽  
...  

Theoretical investigations on cnoidal waves interacting with breakwater resting on permeable elastic seabed are presented in this paper. Based on the shallow water reflected wave theory and Biot consolidation theory on wave-induced seepage pressure, the analytical solutions to first order cnoidal wave reflection and wave-induced seepage pressure are obtained by the eigenfunction expansion approach. Numerical results are presented to show the effects of depth of water, breakwater geometry on cnoidal wave-induced seepage uplift force and overturning moment. Compared with Airy wave theory, in certain shallow water conditions, the shallow water wave theory can more effectively illustrate wave nonlinearity effect in wave load prediction.


1979 ◽  
Vol 94 (1) ◽  
pp. 129-161 ◽  
Author(s):  
J. D. Fenton

A method is outlined by which high-order solutions are obtained for steadily progressing shallow water waves. It is shown that a suitable expansion parameter for these cnoidal wave solutions is the dimensionless wave height divided by the parameter m of the cn functions: this explicitly shows the limitation of the theory to waves in relatively shallow water. The corresponding deep water limitation for Stokes waves is analysed and a modified expansion parameter suggested.Cnoidal wave solutions to fifth order are given so that a steady wave problem with known water depth, wave height and wave period or length may be solved to give expressions for the wave profile and fluid velocities, as well as integral quantities such as wave power and radiation stress. These series solutions seem to exhibit asymptotic behaviour such that there is no gain in including terms beyond fifth order. Results from the present theory are compared with exact numerical results and with experiment. It is concluded that the fifth-order cnoidal theory should be used in preference to fifth-order Stokes wave theory for wavelengths greater than eight times the water depth, when it gives quite accurate results.


Author(s):  
K. A. Belibassakis ◽  
Th. P. Gerostathis ◽  
G. A. Athanassoulis

In the present work, a complete, phase-resolving wave model is coupled with an iterative solver of the mean-flow equations in intermediate and shallow water depth, permitting an accurate calculation of wave set-up and wave-induced current in intermediate and shallow water environment with possibly steep bathymetric variations. The wave model is based on the consistent coupled-mode system of equations, developed by Athanassoulis & Belibassakis (1999) for the propagation of water waves in variable bathymetry regions. This model improves the predictions of the mild-slope equation, permitting the treatment of wave propagation in regions with steep bottom slope and/or large curvature. In addition, it supports the consistent calculation of wave velocity up to and including the bottom boundary. The above wave model has been further extended to include the effects of bottom friction and wave breaking, which are important factors for the calculation of radiation stresses on decreasing depth. The latter have been used as forcing terms to the mean flow equations in order to predict wave-induced set up and mean flow in open and closed domains. Numerical results obtained by the present model are presented and compared with predictions obtained by the mild-slope approximation (Massel & Gourlay 2000), and experimental data (Gourlay 1996).


Author(s):  
Yuzhu Li ◽  
Tian Tang ◽  
Muk Chen Ong

In order to prevent the future risk of soil and structural failures, it is essential to evaluate the dynamic seabed soil behaviors in the vicinity of the offshore foundations under dynamic wave loadings. Three-dimensional (3D) numerical analysis is conducted on the interaction between waves, seabed soil and a gravity-based wind turbine foundation. An OpenFOAM based numerical code developed by Tang [1]for wave-structure-seabed interaction is applied. The nonlinear waves are modeled by solving the Navier-Stokes equations for incompressible flow. The dynamic structural response of the foundation is computed using a linear elasticity solver. The transient responses of the seabed are solved by an anisotropic poro-elastic soil solver. The dynamic interaction between different physical domains is implemented by boundary condition coupling and updating in the integrated FVM based framework. The dynamic wave pressure on the structure and the seabed, the elastic responses of the structure and the changes of the pore pressure, shear stress and seepage flow structure in the seabed are investigated. Highest wave-induced shear stress along the foundation is predicted by solving the deformable structure model. For the seabed soil in the vicinity of the foundation, it is found that the presence of the foundation affects the soil responses by amplifying the wave induced shearing effect on the underlying seabed. Vertical distributions of the pore pressure in the seabed beneath the foundation are investigated with different angles relative to the wave propagation direction. A parametric study of isotropic and anisotropic soil permeability is performed and demonstrates that for the simulated soil in this work, the consideration of the anisotropic permeability is suggested.


2014 ◽  
Vol 501-504 ◽  
pp. 2060-2064
Author(s):  
Hua Huang ◽  
Rui Zhi Chen ◽  
Qi Li ◽  
Jie Min Zhang ◽  
Lin Guo

The influence of the porosity of the structure on the shallow water wave-Induced seepage force on the bottom of porous vertical circular cylinder resting on porous elastic seabed has been investigated. Based on the shallow water diffracted wave theory and Biot consolidation theory on wave-induced seepage pressure, the analytical solutions to first order cnoidal wave diffraction by porous vertical circular cylinder and wave-induced seepage pressure are obtained by the eigenfunction expansion approach. Numerical results show that cnoidal wave-induced uplift and moment may have same order of magnitude as the horizontal cnoidal wave force and moment , and the body porosity of the structure may lead to a reduction both in direct cnoidal wave forces and in the cnoidal wave induced seepage moment. Compared with Airy wave theory, in certain shallow water conditions, the shallow water wave theory can more effectively reflect wave nonlinearity effect in wave load prediction.


2011 ◽  
Vol 45 (3) ◽  
pp. 69-76 ◽  
Author(s):  
Tom Fedenczuk ◽  
Eva-Marie Nosal

AbstractShallow water acoustics provide a means for monitoring and surveillance of near-shore environments. This paper describes the current and future capabilities of the low- to high-frequency Hawaii Experimental Acoustics Range (HEAR) that was designed to facilitate a wide range of different shallow water acoustics experiments and allow researchers from various institutions to test various array components and configurations. HEAR is a portable facility that consists of multiple hydrophones (12‐16) cabled independently to a common central node. The design allows for variable array configurations and deployments in three modes: experimental (off boats and piers), autonomous, and cabled. An application of HEAR is illustrated by the results from a deployment at Makai Research Pier, Oahu, Hawaii. In this deployment, HEAR was configured as a long-baseline range of two volumetric subarrays to study passive acoustic tracking capabilities in a shallow water environment.


2008 ◽  
Vol 124 (3) ◽  
pp. EL157-EL162 ◽  
Author(s):  
D. P. Knobles ◽  
S. M. Joshi ◽  
R. D. Gaul ◽  
H. C. Graber ◽  
N. J. Williams

1995 ◽  
Vol 69 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Daniel B. Blake ◽  
Keith Sturgeon

Aldebarania arenitea (Astropectinidae; Asteroidea; Echinodermata) is described from the Rocky Point Member of the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina. A turbulent, shallow-water environment is suggested by sedimentary features, a diverse marine fauna, and the morphology of Aldebarania. Aldebarania appears to be a partial ecological equivalent of living Astropecten and Luidia; however, phylogenetic relationships within the Astropectinidae are unstudied and the origin of similarities is unknown.


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