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Safety System for Giant Dams

#G-701


Development of a Security System for Giant Dams on the Example of the Inguri Power Station

Tech Area / Field

  • ENV-MRA/Modelling and Risk Assessment/Environment
  • OTH-BIT/Building Industry Technology/Other

Status
3 Approved without Funding

Registration date
12.03.2001

Leading Institute
Tbilisi State University (Zugdidi Branch), Georgia, Zugdidi

Collaborators

  • Florida State University / Institute for International Cooperative Environmental Research, USA, FL, Tallahassee

Project summary

It is known that on 2 December 1959, the Malpasset Dam, close to the city of Frejus near St. Tropez in the south of France, suddenly collapsed. A wall of water burst into the narrow valley, filling its cross-section to a height of 50m, collecting clay, rocks, and vegetation in enormous amounts. Ten minutes later, by then “only” 5m high, the 1.5km wide wave reached the city of Frejus, 9km away, devastating the majority of the homes of its 14000 people, industry, infrastructure, woods and farmland, leaving a stone-polished canyon behind.
With account of the engineering and construction similarities between Malpasset and Inguri dams, it is not excluded that a similar disaster could take place in the Inguri Valley. However, in this case the size of the catastrophe would be much larger because of the much larger size of the Inguri Dam. The Malpasset Dam crest had a length of 225m and was 59m high. In comparison, the Inguri Dam has a crest length of 680m and a height of 272m. Our risk analysis estimations show that the risk-potential of the Inguri Dam is nearly 200 times higher than for the Malpasset Dam.
The reason for the Malpasset catastrophe was that after a week of intense rainfall the dam had shown cracks hours before the crash, but the signals had not been taken seriously.
Generally, water reservoirs created by high dams significantly modify the natural deformation-stress field of the surrounding mountain slopes and increase the intensity of filtration and geological processes. This leads to an increase in the probability of mountain slides or the fall of rocks into the reservoirs.
In case of the Inguri Dam additional negative circumstances increase the risk potential: the dam location is right at the joint of two active tectonic plates, in close vicinity of the dormant volcanic chain of the Elbrus mountains. Another is the presence of an unknown number of contact-mines, remnants from the 1992-93 Abchasian conflict, on the right bank of the Inguri. As most of them are made of plastic they will float downstream, some exploding, leaving a dangerous fraction at unexpected locations, thus jeopardizing any rescue operations.
The aim of the Project is to study these problems with the help of specially developed programs and methods and to work out a system of security for giant dams. This will help to eliminate or decrease the probability of possible catastrophes. Our research will calculate the effects of a possible Inguri Dam crash for Georgia and other countries of the Black Sea Basin and to elaborate an evacuation-rescue plan to decrease the death toll to a minimum.
Finally, the obtained results and recommendations of the Project can be used in the construction of high dams.


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