The effect of changes in sealing wall and horizontal drainage of Golfaraj dam on the values of lifting pressure parameters and maximum outlet gradient

Dams are always considered as infrastructure structures and have vital value. An earthen dam is a body consisting of discontinuous soil particles of various sizes that need to be placed in front of a stream of water to store it. As water is stored behind the dam and its surface area increases, the potential energy of the water particles increases and due to its porous nature, it begins to move in it. Today, the main problem that has attracted the attention of engineers is the issue of seepage. So that the presence of seepage in earthen dams is inevitable. The aim of the present study was to investigate the different positions of the sealing wall and to select the best angle, length, number and distance, as well as to select the appropriate length for horizontal drainage Due to the geotechnical conditions, it is against the phenomenon of rug and lifting force. GeoStudio software is a collection of soil mechanics software based on finite element method through which various modellings and analyzes can be examined. This software includes various models such as SEEP / W which is used for flow analysis and seepage. In the present study, the SEEP / W model of this software package has been used. The SEEP / W model is based on the Darcy relation, which expresses the passage of water flow through the soil in both saturated and unsaturated states. The results showed that for the sealing wall located above the core, an angle of 20 degrees and for the sealing wall located downstream of the core, an angle of 100 degrees are suitable. Also, the optimal length of the sealing wall is 24 meters and its optimal number is 2. Increasing the distance between the two vertical sealing walls has increased the lifting pressure and reduced the maximum outlet gradient. Increasing the horizontal drainage length reduced the maximum output gradient, while having little effect on the uplift pressure.