Filtration regime and stability of the earth dam during reservoir drawdown

The results of numerical investigations of the filtration regime and stability of an earth dam under reservoir drawdown are considered. The problem of unsteady filtration in a homogeneous earth dam is solved. The parameters of the filtration flow are determined: the position of the depression surface, the values and direction of filtration gradients and flow velocities. The changes in the maximum filtration gradients and the probability of filtration deformations are analyzed. Calculations are made to assess the stability of the upstream slope during the stages of reservoir drawdown with different velocities. It is shown that a dam with a large stability margin when the reservoir is full may lose it and be destroyed in the process of drawdown. Conclusions are drawn about the necessary measures to ensure reliability and safety during operation of the structure.