The effect of horizontal drainages on the stability of the Choghart Bafgh tailings dam

Tailings dams refer to structures constructed to stack tailings and industrial waste of mineral processing plants. Generally, Tailings dam is typically an embankment dam. The stability of the dam walls is one of the important issues in these structures, as seepage from inside the body and under the foundation is one of the most important factors in the destruction of these structures. Various solutions can be adopted to prevent this problem, the most common of which is the use of horizontal drainage. The reservoir water level drops rapidly even under rapid drawdown conditions, while the pore water pressure within the core and body does not have a chance to dissipate due to their permeability. This creates a pressure gradient between the reservoir and the dam body, and the excess pore water pressure created reduces the effective stress and, consequently, the shear strength in the body. Furthermore, there is no longer any hydrostatic pressure of the reservoir water, which was also a stabilizing factor. This study examines the stability of the Choghart mine tailings dam, which is about ۲۴۷,۵۰۰ square meters in area, with a maximum height of ۲۲ meters in the southern part of the dam walls. First, the geometric characteristics of this structure were considered and geometric modeling was performed to investigate the stability of the dam, and the stability of the structure was investigated using the geostudio ۲۰۱۰ software and it was observed that it was the most unstable state for the upstream slope at a drawdown rate of ۱.۸ meters per day on the fifth day of rapid drawdown. Then, the stability results were obtained by placing a horizontal drainage with different thicknesses and lengths in the initial model, and compared with the results of the initial model, and it was observed that the factor of safety (FOS) increases with increasing the length of this drainage. Another noteworthy point is that as the thickness of the drainage increases over equal lengths, the FOS increases, and this increase is significant over larger lengths.

کلیدواژه ها:

tailings dam ، slope stability ، horizontal drainage ، Choghart Bafgh tailings dam ، embankment dam safety factor (FOS)