A new analytical solution for water table fluctuations in coastal aquifers with sloping beaches

Teo, H. T.; Jeng, Dong‐Sheng; Seymour, Brian; Barry, David Andrew; Li, Ling

doi:10.1016/j.advwatres.2003.08.004

Cited by 105 publications

(133 citation statements)

References 8 publications

(42 reference statements)

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“…Given that the inundation process is very rapid in comparison to the permeability of the sand, these fluctuations are expected to be quite small and should not change the results significantly. Further exploration of this aspect, however, can be found in Nielsen [23] and Teo et al [37]. Constitutive parameters used for the FE analysis are given in Table 1.…”

Section: Subsurface Pore Water Pressure Simulatormentioning

confidence: 99%

Liquefaction potential of coastal slopes induced by solitary waves

et al. 2009

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Tsunami runup and drawdown can cause liquefaction failure of coastal fine sand slopes due to the generation of high excess pore pressure and the reduction of the effective over burden pressure during the drawdown. The region immediately seaward of the initial shoreline is the most susceptible to tsunami-induced liquefaction failure because the water level drops significantly below the still water level during the set down phase of the drawdown. The objective of this work is to develop and validate a numerical model to assess the potential for tsunamiinduced liquefaction failure of coastal sandy slopes. The transient pressure distribution acting on the slope due to wave runup and drawdown is computed by solving for the hybrid Boussinesq-nonlinear shallow water equations using a finite volume method. The subsurface pore water pressure and deformation fields are solved simultaneously using a finite element method. Two different soil constitutive models have been examined: a linear elastic model and a non-associative Mohr-Coulomb model. The numerical methods are validated by comparing the results with analytical models, and with experimental measurements from a large-scale laboratory study of breaking solitary waves over a planar fine sand beach. Good comparisons were observed from both the analytical and experimental validation studies. Numerical case studies are shown for a full-scale simulation of a 10-m solitary wave over a 1:15 and 1:5 sloped fine sand beach. The results show that the soil near the bed surface, particularly along the seepage face, is at risk to liquefaction failure. The depth of the seepage face increases and the width of the seepage face decreases with increasing bed slope. The rate of bed surface loading and unloading due to wave runup and drawdown, respectively, also increases with increasing bed slope. Consequently, the case with the steeper slope is more susceptible to liquefaction failure due to the higher hydraulic gradient. The analysis also suggests that the results are strongly influenced by the soil permeability and relative compressibility between the pore fluid and solid skeleton, and that a coupled solid/fluid formulation is needed for the soil solver. Finally, the results show the drawdown pore pressure response is strongly influenced by nonlinear material behavior for the full-scale simulation.

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Section: Subsurface Pore Water Pressure Simulatormentioning

confidence: 99%

Liquefaction potential of coastal slopes induced by solitary waves

et al. 2009

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“…Teo et al (2003) also indicated that the shallow water parameter is usually small in real environments and suggested its value ranging from 0.1 to 0.6 in their simulations. Therefore, an additional constraint, ε < 0.6, was imposed during the search of a set of trial solutions for k/n e , ω 1 , and D to ensure that the constraint on the shallow water parameter ε is not violated.…”

Section: Simulated Annealingmentioning

confidence: 85%

“…Moreover, both models relied on the Boussinesq equation that was solved only by the zero-order approximation in shallow water expansion. On the other hand, Teo et al (2003) developed a higher-order analytical solution based on the shallow water expansions for the water table fluctuations induced by the monochromatic tide in a sloping coastal aquifer. Jeng et al (2005) further considered the effect of bichromatic tide in the development of solution for WWL fluctuations in a sloping coastal aquifer.…”

Section: Introductionmentioning

confidence: 99%

Estimations of tidal characteristics and aquifer parameters via tide-induced head changes in coastal observation wells

Chen

Yeh

et al. 2011

Hydrol. Earth Syst. Sci.

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Abstract. The groundwater fluctuations due to tidal variations at an observation well in a coastal aquifer can be used to determine the tidal characteristics and aquifer parameters without conducting an aquifer test. In this study, a method, comprised of Jeng et al. 's solution (2005) and simulated annealing (SA) algorithm, is developed to determine the coastal aquifer parameters (hydraulic diffusivity, beach slope, and aquifer thickness) as well as the tidal characteristics (bichromatic-tide amplitudes, bichromatic-tide wave frequencies, and tidal phase lag) from the analysis of the tideinduced well-water-level (WWL) data. The synthetic WWL data generated from Jeng et al. 's solution (2005) with assumed parameter values and field data obtained from Barrenjoey beach, Australia, are analyzed. The estimated parameter values obtained from analyzing synthetic WWL data by the present method show good agreements with the previously assumed parameter values. The parameter estimation procedure may however fail in the case of a large shallow water parameter which in fact violates the constraint on the use of Jeng et al. 's solution (2005). In the analysis of field WWL data, the results indicate that the aquifer parameters estimated from the present method with single or multiple well data are significantly different from those given in Nielsen (1990). Inspecting the observed WWL data and the WWL data predicted from Jeng et al. 's solution (2005) reveals that the present method may provide better estimations for the aquifer parameters than those given in Nielsen (1990).

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“…Teo et al [4] considered hydraulic conductivities in the range 50-1000 m/day, with aquifer depths of 5-10 m and tidal amplitudes of 1-2 m, while Nielsen [2] considered tidal amplitudes and aquifer depths on the order of 0.5 m, with hydraulic conductivities on the order of a few mm/day. Given a soil porosity in the range 0.2-0.4 and considering semi-diurnal and diurnal tides, these values correspond to parameter values in the range 0.1 to 0.6.…”

Section: Solution Methodsmentioning

confidence: 99%

“…Numerical modelling by Ataie-Ashtiani et al [1] indicates that under certain conditions vertical flows are significant. The effect of vertical flows on the groundwater response was investigated by Teo et al [4] using pertur-C642 bation expansions under the assumptions of a shallow aquifer and small tidal amplitude. Although Teo et al and Nielsen gave their solutions for beach slopes in the range 0-π/2, the nature of the perturbation expansions is such that for sufficiently shallow beaches the solutions exaggerate the observed features and indicate unphysical behaviour.…”

Section: Introductionmentioning

confidence: 99%

Groundwater response to tidal forcing

Roberts¹

2008

ANZIAMJ

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The groundwater response to tidal forcing in a phreatic aquifer is modelled using a perturbation approach for the case of a shallow beach. The principal features of the groundwater response, namely the super-elevation of the water table, attenuation of the forcing wave and the asymmetry and phase shift in the fluctuations, is investigated and compared with earlier solutions. These results demonstrate the importance of correctly including the beach slope effects to prevent the exaggeration of observed features for shallow beaches. A general solution method is presented, which provides an efficient method for obtaining higher order solutions.

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A new analytical solution for water table fluctuations in coastal aquifers with sloping beaches

Cited by 105 publications

References 8 publications

Liquefaction potential of coastal slopes induced by solitary waves

Liquefaction potential of coastal slopes induced by solitary waves

Estimations of tidal characteristics and aquifer parameters via tide-induced head changes in coastal observation wells

Groundwater response to tidal forcing

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