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Showing 3 results for Hydraulic Gradient
The Effects of Some Peripheral Conditions on the Solubility of Gypiferous Soils
N. Abbasi, A. A. Afsharian,
Volume 22, Issue 1 (6-2018)
Abstract
Gypsiferous soils are one of the problematic soils which, due to solubility and contact with water, are a threat to various civil structures, especially water structures. Various factors affect the rate and amount of gypsum particles solubility. Gypsum types, the soil texture, the amount of gypsum in soil, the hydraulic gradient, and temperature and flowing water from gypsum soil are the major factors affecting the quality and quantity of the gypsum solution. In this research, the effects of some peripheral conditions including water temperature and hydraulic gradient on the solubility of gypsum soils were studied. To this aim, samples of gypsum soils were provided artificially by adding various rates of the natural gypsum rock including 0, 5, 10, 20 and 30 percent by weight of clay soil. Then, all gypsum soils were leached under five hydraulic gradients levels including 0.5, 1, 2, 5 and 10. The results indicated that the rate of Gypsum in the soil had a direct effect on the rate of solution in a way that by increasing the percent of Gypsum, the rate of solubility was increased. Also, the rate of leaching (the rate of the derived Gypsum from soil to the primary rate of Gypsum) was decreased by increasing the rate of Gypsum. In addition, by increasing hydraulic gradient, the speed of water and its amount in soil environment within a specified time were raised; further the rate of gypsum was increased too. Also, it was found that the rate of the solubility was increased directly by the temperature. The solubility rate of the gypsum soil at 50 C0 was found to be 2.5 and 1.6 times greater than that of the soil at 5 and 20 C0, respectively.

Determining the Thickness of the Filter Layers to Protect the Upstream Sideslope of the Homogeneous Earth Dam Due to Rapid Drawdown Condition with Experimental and Numerical Models
H. Azadbeygi, M. Najarchi, Dr H. Lajevardi,
Volume 27, Issue 4 (12-2023)
Abstract
The present research explores the experimental and numerical investigation of homogeneous earth dams in rapid drawdown conditions. The numerical model was evaluated and calibrated due to the saturation status using the experimental model. The calculated error between the piezometric pressure data and the seepage line in the numerical and experimental model indicated that the results of the Seep/W numerical model data had acceptable accuracy. Also, to determine the thickness of the filter adjusted in the upstream side slope of the homogeneous earth dam in rapid drawdown condition, input data to the numerical model including hydraulic conductivity, rate of the water level drop (depletion of the dam reservoir in three scenarios of 2, 3, and 4 days), the different side slopes of the body (m = 1, 2, and 3), and the thickness of the filter layers were determined. It is worth mentioning that the number of layers and the soil properties of the filter materials were determined based on the USBR which consisted of three types of soil structure (sand, gravel, and gravel with sand). The maximum hydraulic gradient of the dam materials was used to estimate the thickness of the filter layers. Finally, some dimensional fewer numbers were presented to estimate the filter layers by changing the input data through the numerical model to attain the safe conditions for the values of the hydraulic gradient at the upstream side slope. Results of the numerical model indicated that for the construction of the dam with the thickness of the presented filter, the values of the available hydraulic gradient at the point of water exit from the upstream side slope of the body of the earth dam were lower than the critical hydraulic gradient of the earth dam materials in rapid drawdown condition.

Analysis of Seepage Flow and Hydraulic Gradient in the Body and Foundation of Alavian Earth Dam
M. Kouhdaragh, M. Majedi Asl, T. Omidpour Alavian, N. Nobahari, M. Ayami Lord,
Volume 28, Issue 4 (2-2025)
Abstract
Dams, as man-made artificial structures, play a significant role in providing water in various sectors, including agriculture, industry, electricity generation, and flood control. Various soil compounds such as sand, clay, and stone are used for the construction and establishment of earth dams. In this research entitled "Investigation and analysis of Seepage flow and hydraulic gradient in the body and foundation of Alaviyan earth dam using SEEP/W software", the effects of Seepage flow and hydraulic gradient in the body and foundation are investigated. This research analyzes the details of this process using SEEP/W software and analyzes the obtained results. Theoretical foundations related to Seepage flow and hydraulic gradient in earth dams and their importance in the stability of dams are discussed as one of the most important issues of civil engineering. Methods of controlling water seepage from earth dams include the use of seals, walls made with grout mortar, impermeable cores, metal shielding, and impermeable blankets upstream of the dam. In this study, drains, seals, and clay blankets are used as water seepage control methods. The results show that the use of a watertight wall reduces the amount of Seepage because this wall prevents water from flowing through the body of the dam. In general, this research ends by providing quantitative results and recommendations to improve the stability of dams and reduce the possibility of risks caused by seepage flow and hydraulic gradient, and the important elements that should be considered in the design and construction of earth dams. Reviews. In this study, the effects and performance of earth dams have been investigated using finite element methods, and the performance of dams has been evaluated. GEOSTUDIO finite element software was used for modeling. The results of modeling include the investigation of parameters such as phreatic lines, the effect of the water level behind the dam, the clay blanket, and the water seal. Also, the leakage rate from the dam has been extracted and analyzed for different states defined in the model.

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