Analysis and Estimation of Seepage Through Earth Dams with Internal Cut Off

2021 ◽  
Author(s):  
Mohamed Abdel Razek ◽  
Adel Abdel Salam ◽  
Michael Attia
Keyword(s):  
Computer Program ◽  
Numerical Analyses ◽  
Earth Dam ◽  
Downstream Face ◽  
Seepage Discharge ◽  
Earth Dams ◽  
Sustainable Operation ◽  
Irrigation Engineering ◽  
Department Faculty ◽  
Earth Fill

Abstract The study of seepage through earth-fill dams is very important for the constructed dams to ensure that the control of seepage is sufficient for the safe and sustainable operation of the dam. It is also important in the design and construction of new dams to ensure that the seepage through and under the dam will be well controlled. Construction horizontal, inclined, trapezoidal or pipe filters one of the dam protection methods. Cut off also can be constructed to minimize seepage discharge directed to the downstream face of the dam. Seepage through an earth dam with internal cut off is experimentally studied in the laboratory of Irrigation Engineering and Hydraulics Department, Faculty of Engineering, Alexandria University, Egypt on a Hele-Shaw model. Also, using computer program SEEP/W (which is a sub-program of Geo-Studio). The experimental and numerical analyses of seepage through earth-fill dam with internal cut off is conducted. Results from solutions are compared with each other.

scholarly journals Effects of core characteristics on seepage through earth dams

2021 ◽  
Author(s):  
Allaa O. Abdel-Kawy ◽  
Nahla M. AboulAtta ◽  
Doaa A. El-Molla
Keyword(s):  
Numerical Models ◽  
Downstream Face ◽  
Seepage Discharge ◽  
Earth Dams ◽  
Core Zone ◽  
The Core ◽  
Core Characteristics ◽  
Vertical Wedge

Abstract In this research, SEEP2D and SEEP/W numerical models are used to simulate seepage through earth dams with internal cores. In order to evaluate the two models' performance, they were compared in cases with no, vertical, and wedge-shaped cores. SEEP/W was then used to study further cases due to its accuracy in drawing the phreatic line within the core zone. The effect of the core's characteristics on the amount of discharge, and the phreatic line's levels at the core's upstream and downstream faces were investigated. Four core types – vertical, wedge-shaped, upstream inclined, and downstream inclined – were considered. Different hydraulic conductivities, upper widths, and core slopes were also evaluated. The wedge-shaped core is the most effective of those investigated in reducing seepage discharge and the phreatic line's level at the core's downstream face, the vertical core came second. Design equations are provided for all the core shapes considered in the study.

Predicting Seepage of Earth Dams Using Neural Network and Genetic Algorithm

2011 ◽  
Vol 403-408 ◽  
pp. 3081-3085 ◽  
Author(s):  
Xin Ying Miao ◽  
Jin Kui Chu ◽  
Jing Qiao ◽  
Ling Han Zhang
Keyword(s):  
Neural Network ◽  
Genetic Algorithm ◽  
Field Data ◽  
Back Propagation ◽  
Earth Dam ◽  
Earth Dams ◽  
Gradient Descent Algorithm ◽  
Levenberg Marquardt ◽  
Lm Algorithm ◽  
Good Agreement

Measurements of seepage are fundamental for earth dam surveillance. However, it is difficult to establish an effective and practical dam seepage prediction model due to the nonlinearity between seepage and its influencing factors. Genetic Algorithm for Levenberg-Marquardt(GA-LM), a new neural network(NN) model has been developed for predicting the seepage of an earth dam in China using 381 databases of field data (of which 366 in 2008 were used for training and 15 in 2009 for testing). Genetic algorithm(GA) is an ecological system algorithm, which was adopted to optimize the NN structure. Levenberg-Marquardt (LM) algorithm was originally designed to serve as an intermediate optimization algorithm between the Gauss-Newton(GN) method and the gradient descent algorithm, which was used to train NN. The predicted seepage values using GA-LM model are in good agreement with the field data. It is demonstrated here that the model is capable of predicting the seepage of earth dams accurately. The performance of GA-LM has been compared with that of conventional Back-Propagation(BP) algorithm and LM algorithm with trial-and-error approach. The comparison indicates that the GA-LM model can offer stronger and better performance than conventional NNs when used as a quick interpolation and extrapolation tool.

Seepage through Earth Dams with Chimney Drain on Pervious Foundation

2012 ◽  
Vol 452-453 ◽  
pp. 538-542 ◽  
Author(s):  
Abdelkader Djehiche ◽  
Rekia Amieur ◽  
Mustafa Gafsi
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Drainage System ◽  
Earth Dam ◽  
Earth Dams ◽  
Drainage Systems ◽  
The Earth ◽  
Excess Water ◽  
Effective Drainage

This paper presents an experimental study of a homogenous earth dam. The work is focused to the search of solutions of problems encountered in the earth dams after their construction. One of the major problems is the choice and design of systems of drainage. The effective drainage system to prevent harmful accumulations of excess water is one of the most important roles of dams. Efficient drainage systems can improve the safety of earth dams. The paper presented herein reports the results obtained from the experimental study. Empiric relations have been obtained which can be help in the control of the flow rate in the chimney drain of the earth dams on pervious foundation, which can increase safety earth dams

scholarly journals Numerical Evaluation of Natural Periods and Mode Shapes of Earth Dams for Probabilistic Seismic Hazard Analysis Applications

Geosciences ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 499
Author(s):  
Paolo Zimmaro ◽  
Ernesto Ausilio
Keyword(s):  
Seismic Hazard ◽  
Critical Issue ◽  
Fundamental Period ◽  
Degree Of Saturation ◽  
Earth Dam ◽  
Mode Shapes ◽  
Probabilistic Seismic Hazard ◽  
Earth Dams ◽  
Dam Foundation ◽  
Geotechnical Characteristics

The evaluation of natural periods and related mode shapes of earth dams represents a critical issue when performing structure-specific probabilistic seismic hazard analyses (PSHA). The identification of critical scenario events, using techniques such as disaggregation of the seismic hazard, and the calculation of a suitable target spectrum for ground motion selection and scaling procedures (e.g., the conditional mean spectrum), require at least the knowledge of the fundamental period of the system. This problem can be solved using analytical, numerical, and/or empirical techniques. We present several linear elastic modal analyses for an earth dam located in Southern Italy, using a numerical solution of the generalized eigenvalue problem obtained by the finite element method (FEM). Our numerical experiments are performed, testing various assumptions on boundary conditions, degree of saturation, and the distribution of geotechnical characteristics of the dam’s materials. We then compare our results against existing analytical solutions. We show that ignoring soil–structure interaction effects due to the flexibility of the dam foundation (i.e., under the assumption of fixed base) can lead to a substantial underestimation of the fundamental period of the dam. This effect should be carefully addressed when modal analysis results are used in PSHA-related applications.

Uncertainty Analysis and Monitoring of Earth Dam

2014 ◽  
Vol 580-583 ◽  
pp. 954-957
Author(s):  
Ling Qiang Yang ◽  
Rui Gao ◽  
Yan Wang
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Probabilistic Method ◽  
Finite Difference Methods ◽  
Earth Dam ◽  
Earth Dams ◽  
Program Code ◽  
Physical Behavior ◽  
Difference Methods

Monte Carlo simulation provides a probabilistic method to evaluate the physical behavior of earth dam. Therefore, the behavior could be got in a more realistic manner. Based on the theory, an innovative software program code is developed by combining the Monte Carlo and finite difference methods to predict the performance of earth dams after impounding. In order to assess the efficiency of the method, the case study of earth dam, located at Southeast of China, has been studied in detail. The performance of this dam is predicted and compared with the field monitoring by using the monitoring data. The results shows the robustness of the proposed method.

scholarly journals Effects of Upstream Water Level on Dynamic Response of Earth Dam

2015 ◽  
Vol 2015 ◽  
pp. 1-12
Author(s):  
Shong-Loong Chen ◽  
Chun-Fu Lin ◽  
James C. Ni ◽  
Meen-Wah Gui
Keyword(s):  
Dynamic Response ◽  
Water Storage ◽  
The Philippines ◽  
Earth Dam ◽  
Mountainous Area ◽  
Earth Dams ◽  
Appropriate Use ◽  
Centrifuge Model ◽  
The Earth ◽  
The Subject

The island of Taiwan is located between the boundaries of the Eurasia and the Philippines Plates and thus earthquakes occurred frequently. The excitation of earthquake affects the integrity of earth dams situated in the mountainous area of the island. A study was conducted to evaluate the dynamic response and safety of one of the earthquake dams. The computer program and soil model used were calibrated for their appropriate use for the subject dam against a well-instrumented centrifuge model. Numerical simulation was then conducted to examine the influence of upstream water storage level on the response of the earth dam. The numerical results identified three locations in the dam where attentions are required because these locations were found susceptible to liquefaction.

Une modélisation théorique nouvelle de la rupture par submersion d'une digue en terre et sa validation

2004 ◽  
Vol 31 (5) ◽  
pp. 797-812 ◽  
Author(s):  
N E Zerrouk ◽  
C Marche
Keyword(s):  
Numerical Model ◽  
Formation Process ◽  
Earth Dam ◽  
Dam Failure ◽  
Second Step ◽  
Dam Breach ◽  
Erosion Mechanism ◽  
Flow Hydraulics ◽  
Earth Fill

This paper presents the EROBAR numerical model on breach formation in earth-fill dams during an overtopping flow. Hydraulics of flow over an earth-fill dam is considered as the basis for the comprehension of the breach formation process. To this will be added the mastery of the erosion mechanism and of widening of the breach canal. As the breach formation process in an earth-fill dam is very complex, the EROBAR model was the object of a two-step formulation, with the two steps joined later. The first step deals with the flow hydraulics, vertical erosion, and longitudinal evolution of the profile of the dam. The second step introduces the widening of the breach, based on the instability of the breach slope. After the two formulations were joined and validated, the EROBAR model was applied to the experimental dyke, to several homogenous earth-fill dams with or without protection, and to zoned dams.Key words: dam failure, breach erosion, earth-fill dam breach, overtopped earth dam, numerical model.

scholarly journals Slope Stability of an Earth Dam during Drawdown Conditions (KHASA-CHAI Dam) as a Case Study

2018 ◽  
Vol 7 (4.37) ◽  
pp. 17
Author(s):  
Adnan Jayed Zedan ◽  
Mariwan Ridha Faris ◽  
Ahmed Amer Abdulsattar
Keyword(s):  
Slope Stability ◽  
Factor Of Safety ◽  
Slip Surface ◽  
Earth Dam ◽  
Downstream Face ◽  
Upstream Slope ◽  
Maximum Water Level ◽  
Water Drawdown ◽  
Action Taking ◽  
Safe Condition

Aiming in this research was to have a clear view about the behavior of Khasa-Chai Dam during the draw down action taking into consideration the newly built of this dam which was filling during the time of this article, the upstream slope was investigated by taking drawdown of the water from the reservoir. This dam is consists of the zoned embankment with a total length of (2.36 km) with an upstream slope (1v:3h) and downstream slope (1v:2h). Slope stability was investigated during the drawdown of the water from the reservoir by considering the water in the reservoir to be at maximum water level and by taking two cases during the rapid and slow drawdown. SLOPE/W which is a sub program from Geo-Slope software was used in association with SEEP/W software to find the factor of safety of the upstream slip surface during the drawdown conditions. It was noticed from the drawdown conditions that the phreatic line falls almost at the same position for both cases. Also for both cases the factor of safety of the upstream slip surface falls above the value of (1.0) and that is mean the upstream slope is in a safe condition when the water drawdown. The exit gradient and the rate of flow at the downstream face decrease with time as the water in the reservoir drawdown which means the factor of safety against boiling increases with time.  

Representativeness of measurements in the interpretation of earth dam behaviour

2006 ◽  
Vol 43 (1) ◽  
pp. 87-99 ◽  
Author(s):  
Luca Pagano ◽  
Stefania Sica ◽  
Augusto Desideri
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Earth Dam ◽  
Measured Quantity ◽  
Pressure Measurements ◽  
Earth Dams ◽  
Pressure Monitoring ◽  
Spatial Continuity ◽  
Numerical Examples

The representativeness of measurements monitored in earth dams is analysed to investigate how a given measured quantity can be used to interpret the dam's mechanical behaviour. Representativeness is evaluated on the basis of spatial continuity of the measured quantity and the sensitivity of that quantity to natural mechanical nonhomogeneity. The discussion is supported by results from case studies and numerical examples. The study is mainly focused on pore-water pressure measurements. Spatial continuity of pore-water pressure is analysed with consideration of both saturation and drainage conditions. The paper discusses how pore-water pressure representativeness can vary over the lifetime of the dam.Key words: earth dam, pore-water pressure, monitoring.

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