Vertical drainage in the foundation of the overflow dam of the Dneprodzerzhinsk hydroelectric station

Conclusions

• 1. The seasonal variations of the discharge and piezometric heads noted in the results of the on-site observations indicate the presence of seasonal deformations of the seepage medium, which with the course of time, evidently, can lead to changes in the state of the contact zone of the dam foundation.

• 2. The results of measuring the temperature of the seepage flow make it possible to distinguish weakened areas of the foundation subject to special monitoring and to estimate the degree of influence of the lower pool on the drainage discharge. According to an approximate evaluation, the inflow from the lower pool does not exceed 10% of the total discharge. The data of the temperature measurements confirm the overall effectiveness of the vertical drainage system for discharge of the flow in the dam foundation.

• 3. The wells of the vertical drainage system, accessible for measuring the discharge and water temperature and also for conducting experiments with tracers, can serve as a means of reliable monitoring of the state of the watertight and drainage devices in the foundations of concrete structures and can give additional valuable information about the development of seepage processes in the foundation of the structure.