Numerical Simulation Using the Finite Element Method to Investigate the Effect of Horizontal Drains and Cutoff Walls on Seepage and Uplift Pressure in Heterogeneous Earth Dams | Chapter 06 | Novel Perspectives of Engineering Research Vol. 9

 Because of the potential hazards and repercussions of dam failure for downstream populations, earth dam design and problems are key considerations both during and after construction. The effectiveness of using cutoff walls and horizontal drains to reduce seepage flow from a conventional heterogeneous earth dam is the subject of this research. The primary goal of this research is to determine an appropriate horizontal drain length in earth dam downstream shells, as well as the ideal location for cut off walls in earth dam foundations. Various cutoff wall depths and horizontal drain lengths are positioned under the earth dam at various sites for this purpose. The numerical simulation method is used to calculate seepage analysis, hydraulic gradient, and uplift pressure (FEM). Results showed that increasing horizontal drain length causes a slight increase in the seepage rate and hydraulic gradient. For limiting seepage and piping/undermining, the best place for a cutoff wall is in the middle of the dam foundation. Seepage from the earth dam and its base is decreased by increasing the cut-off wall depth. Changing the cutoff wall's placement has little impact on the exit hydraulic gradient, which is always less than unity. When a cutoff wall is installed in the middle of the foundation, the hydraulic gradient is reduced by 20% compared to a cutoff wall installed upstream of the dam.

Author(S) Details

Farzin Salmasi
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

John Abraham
University of St. Thomas, Minnesota, School of Engineering 2115 Summit Avenue St. Paul, Minnesota 55105, USA.

View Book:- https://stm.bookpi.org/NPER-V9/article/view/6296

Comparison of Uplift Pressure and Hydraulic Gradient in Three Types of Dams: Concrete Gravity Dams, Homogeneous and Heterogeneous Earth-Filled Dams | Chapter 06 | Innovations in Science and Technology Vol. 3

 Dams are among the oldest hydro-engineering structures on the planet. They're built to prevent flooding and protect land, property, people, and cattle. Dam designers must understand uplift pressure and hydraulic gradient since they have an impact on the dam's stability. Dam stability relates to the dam's ability to withstand sliding, overturning, and maximum stresses (tension or compression) applied to its foundation. The hydraulic gradient and uplift pressure in three types of dams, namely homogeneous earth dams, heterogeneous earth dams, and concrete gravity dams, are the subjects of this research. The numerical simulation method was used to calculate seepage, hydraulic gradient, and uplift pressure (FEM). The FEM receives the dam shape, material, computational mesh, and boundary conditions (BCs). The hydraulic gradients for two types of dams, the concrete gravity and the homogenous earth dam, were similar and less than 0.5, according to the findings. However, the hydraulic gradient at the beginning and end of the clay core heterogeneous earth dam was greater than 2.5. To prevent the dam foundation from piping/undermining, filter material will need to be installed in certain zones. The two earth dams have higher uplift pressures than the concrete gravity dam. Uplift pressure for earth dams is thought to be safe since the enormous width of earth dams prevents them from overturning.

Author(S) Details

Farzin Salmasi
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

John Abraham
University of St. Thomas, Minnesota, School of Engineering 2115 Summit Avenue St. Paul, Minnesota 55105, USA.

View Book:- https://stm.bookpi.org/IST-V3/article/view/5457

Validity of Schaffernak and Casagrande Analytical Solutions for Seepage through a Homogeneous Earth Dam and Comparison with Numerical Solutions Based on the Finite Element Method | Chapter 7 | Novel Perspectives of Engineering Research Vol. 4

 Because of its uses in reservoir management, seepage from earth dams is an essential topic to research. The loss of water owing to seepage is a significant concern for hydraulic designers. Water logging, salinization, groundwater contamination, and health concerns are all caused by seepage loss, which depletes fresh water resources. This study offers numerical and analytical solutions for seepage from a homogeneous earth dam resting on an impervious foundation. For this, a steady-state two-dimensional (2D) flow through a homogeneous earth dam is investigated. The finite element approach is used to calculate the position of the phreatic line (FEM). The numerical simulation results are compared to Schaffernak and Casagrande's analytical solutions. The numerical solution, as opposed to the Casagrande and Schaffernak approaches, forecasts higher seepage. Schaffernak's solution has a greater than 20% mistake rate, whereas Casagrande's solution has a greater than 30% error rate. Both Schaffernak and Casagrande's answers, on the other hand, are for simple cases: I a homogeneous embankment; (ii) an embankment dam standing on top of an impervious base. In FEM simulation, none of these assumptions or simplifications are required. This research demonstrates FEM's capacity to predict water flow in a porous medium with complex characteristics such as non-homogeneous (heterogeneous) embankment dams, non-isotropic soils, pervious foundations, and a variety of boundary conditions.

Author(S) Details

Farzin Salmasi
Department of Water Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.

John Abraham
University of St. Thomas, Minnesota, School of Engineering 2115 Summit Avenue St. Paul, Minnesota 55105, USA.

View Book:- https://stm.bookpi.org/NPER-V4/article/view/5107