A Novel Boundary-Type Meshless Method for Modeling Geofluid Flow in Heterogeneous Geological Media

Xiao, Jing-En; Ku, Cheng-Yu; Liu, Chih-Yu; Yeih, Weichung

doi:10.1155/2018/9804291

Cited by 5 publications

(4 citation statements)

References 27 publications

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“…The corresponding Gardner parameters were calculated using (12). From Figure 12, it is found that the SWCC based on the Gardner model provides acceptable agreement with the van Genuchten model.…”

Section: Geofluidsmentioning

confidence: 99%

“…Consequently, shallow landslides may often occur within the vadose zone under unsaturated soil conditions [5][6][7]. The prediction of flow in transient conditions is important in engineering practice while considering the stability of unsaturated soil slopes [8][9][10][11][12] or poromechanical coupling influence for rainfall-induced shallow landslides in unsaturated soils [13,14].…”

Section: Introductionmentioning

confidence: 99%

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Modeling of Transient Flow in Unsaturated Geomaterials for Rainfall-Induced Landslides Using a Novel Spacetime Collocation Method

Liu

et al. 2018

Geofluids

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The modeling of transient flow in unsaturated soils for rainfall-induced landslides using a novel spacetime collocation method is presented. A numerical solution obtained in the spacetime coordinate system is approximated by superpositioning Trefftz basis functions satisfying the linearized Richards equation for collocation points on the spacetime domain boundary. The Gardner exponential model is adopted to derive the linearized Richards equation to describe the soil-water characteristic curve in unsaturated soils. To deal with the rainfall-induced landslides, the infinite slope stability analysis coupled with the proposed meshless method with the consideration of the fluctuation of time-dependent matric suction is developed. The proposed method is validated for several test problems. Application examples of transient modeling of flow for rainfall-induced landslides in homogenous unsaturated soils are also conducted. Numerical results demonstrate that the proposed method is highly accurate to deal with transient flow in unsaturated soils for rainfall-induced landslides. In addition, it is found that the numerical method using the Richards equation with the Gardner model may provide a promising solution for different soil textures.

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Section: Geofluidsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Modeling of Transient Flow in Unsaturated Geomaterials for Rainfall-Induced Landslides Using a Novel Spacetime Collocation Method

Liu

et al. 2018

Geofluids

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“…, f j denote the boundary values for Dirichlet and Neumann boundary conditions, respectively. In this article, we adopt the domain decomposition method (DDM) [37,38] to solve the nonlinear moving boundary problems in heterogeneous geological media. The DDM is commonly used to solve the problem with different physical characteristics in each subdomain.…”

Section: The Characteristic Lengthmentioning

confidence: 99%

On Solving Nonlinear Moving Boundary Problems with Heterogeneity Using the Collocation Meshless Method

Xiao

Liu

2019

Water

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In this article, a solution to nonlinear moving boundary problems in heterogeneous geological media using the meshless method is proposed. The free surface flow is a moving boundary problem governed by Laplace equation but has nonlinear boundary conditions. We adopt the collocation Trefftz method (CTM) to approximate the solution using Trefftz base functions, satisfying the Laplace equation. An iterative scheme in conjunction with the CTM for finding the phreatic line with over–specified nonlinear moving boundary conditions is developed. To deal with flow in the layered heterogeneous soil, the domain decomposition method is used so that the hydraulic conductivity in each subdomain can be different. The method proposed in this study is verified by several numerical examples. The results indicate the advantages of the collocation meshless method such as high accuracy and that only the surface of the problem domain needs to be discretized. Moreover, it is advantageous for solving nonlinear moving boundary problems with heterogeneity with extreme contrasts in the permeability coefficient.

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“…In the recent past, numerical modeling has gained more interest and has become an important tool for defining and tackling geological problems [22][23][24]. Technological progress has been simplifying the process of understanding soil behavior under different loading perspectives [25].…”

Section: Introductionmentioning

confidence: 99%

Archives of Civil Engineering

Utepov,

Lechowicz,

Zhussupbekov

et al. 2022

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A fast reduction of a reservoir level may result in instability of an earth dam caused by the high pore water pressures that remain relatively high in the embankment. Moreover, the dissipation of the accumulated pore water pressures is highly dependent on the permeability of the materials used for the embankment and the storage characteristics of the reservoir. Therefore, in the design of embankment dams, the stability analysis under rapid drawdown loading conditions is an important design case. In this study, the influence of different permeability rates on dam stability under different cases of rapid drawdown was investigated using the finite element method in SEEP/W and SLOPE/W of the GeoStudio with a case of the Lugoda dam in Ndembera catchment, Tanzania. The modeling process considers the time-dependent hydraulic conditions and the transient flow conditions using different water levels during rapid drawdown for evaluation of the factor of safety. From the 1m per day drawdown rate; the lowest minimum factor of safety value (0.90) was obtained from the 10 −7 m/s material permeability of the upstream zone of the dam. It means that, at a drawdown rate of 1m per day, there is a potential for failure of the embankment if the hydraulic conductivity value will be somewhere below 10 −6 m/s.

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A Novel Boundary-Type Meshless Method for Modeling Geofluid Flow in Heterogeneous Geological Media

Cited by 5 publications

References 27 publications

Modeling of Transient Flow in Unsaturated Geomaterials for Rainfall-Induced Landslides Using a Novel Spacetime Collocation Method

Modeling of Transient Flow in Unsaturated Geomaterials for Rainfall-Induced Landslides Using a Novel Spacetime Collocation Method

On Solving Nonlinear Moving Boundary Problems with Heterogeneity Using the Collocation Meshless Method

Archives of Civil Engineering

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