Repair of pipe drainage system of a dam under active head

Conclusions

• 1. The piping of sand from the body of the dam in zone PK 42+80 and disruption of the reverse filter of the drainage system was the result of the poor quality of the reverse filter installation in the construction period.

• 2. Under conditions of active head on the dam, the repairing of a reverse filter, even in a small section of the drainage system, is very laborious work, which can be carried out under operating conditions in 45 days, and with better work organization in less time.

• 3. It is especially necessary to carry out the repair of the drainage system diligently during joining of the new reverse filter with the old one in the zones which are still sound, not permitting the fractions of the various mechanical compositions to become intermingled under the action of the longitudinal filtrations.