Determining the reliability of concrete dams through diagnosis of their bedrock

Conclusions

• 1. Dams, particularly concrete bedrock dams, have long been used by society to meet the needs of human society, especially to reduce the risk of catastrophes on rivers as a consequence of floods. However, dams themselves experience failures. The risk of human losses as a result of the collapse of dams is, according to the most careful estimates, two orders of magnitude lower than that attributable to unforeseen floods on uncontrolled water courses.

• 2. Hydraulic structures are complex systems whose reliability depends on its individual subsystems. For concrete bedrock dams most failures are due to underestimation of the properties of the base of the dam. With the development of different forms of ownership of hydraulic pressure structures, the reliability of dams must be made the responsibility of state management.

• 3. The dam failure database now covers 222 concrete dams. The information that has been obtained may be used to select possible failure models that may be used in the design of concrete dams. Our data indicate that nearly 80% of all failures occur in the process of filling and operating the reservoir, which underscores the value of estimations of the properties of the structure systems, particularly those having to do with the bedrock, when the structure system is affected by design loads.

• 4. Careful field investigations are needed to understand the process of crack formation in the base of dams from the pressure face of concrete dams using a previously developed technique involving joint static and filtration tests.