Provision for stability of slopes in the area of basic structures of the Zagorsk pumped-storage hydroelectric station

Conclusions

• 1. Provision for stability of slopes is one of the main problems in designing plains PSHS.

• 2. The reasons for occurrence and a “chain reaction” of development of landslide phenomena on the south slope of the area of basic structures of the Zagorsk PSHS were peculiarities of its engineering-geological structure that were not properly taken into account in designing and carrying out construction work.

• 3. For the purpose of stabilizing the landslide slope, a system of engineering measures was developed and implemented, including a change in the configuration and structure of the right-bank abutment of the upper-basin levee to the water intake, construction of a banquette, filling of a counterbanquette, draining of moraine loams, grading of the slope, surface water diversion, and monitoring of the state of the slope and elements of the antilandslide protection.

• 4. Data from full-scale observatins indicate the effectiveness of the antilandslide measures that were performed and a state of the slope corresponding to criteria for the hydro development's safe operation.

• 5. Innovative elements of the system of measures to stabilize the south landslide slope of the Zagorsk PSHS are:

• the complex nature of measures, providing for the optimum set of criteria with respect to reliability, technological efficiency, construction time, and cost of adjusted expenditures;

• minimization of one-time and total excavation for the banquette, providing for the least disruption of the slope in the process of construction;

• draining of moraine loams, which has no known analog;

• the use of an ejector unwatering system, which provides for minimum adjusted expenditures on construction and operation of the drainage system.