Slope stability at the Zagorsk pumped-storage station: lessons in surveying, design and construction

The course of investigations about the stability of the slopes in the Zagorsk pumped-storage station at various stages of design and construction are traced. Insufficient attention to a study of the structure of the moraine mass led to an underestimation of its inhomogeneity and signs of occurrence of complex gravitational processes in it. Due attention was not devoted to calculations of stability and therefore basic rules of conducting works on slide stretches were violated. Serious complications related to disturbance of the stability of natural slopes and the slopes of construction excavations occurred. Stabilization was achieved by introducing relief wells, removing the slide masses and replacing them with high quality soil.