Enlarging the underground hydroelectric plant at Villarino, Spain

Conference · Thu May 01 04:00:00 EDT 1997

OSTI ID:469026

Oriard, L L

Near the village of Villarino de los Aires, in the province of Salamanca, Spain, was an existing underground hydroelectric power plant. A major enlargement was undertaken to increase the electrical generating capacity, under a contract awarded to a joint venture of Dragados y Construcciones, S. A. (Spain), Entrecanales y Tavora, S. A. (Spain), and S.A. Conrad Zschokke (Switzerland). The enlargement required the excavation of a large and complex underground system of tunnels, shafts and chambers adjacent to existing facilities and interconnected with these facilities. The existing machine hall and transformer chamber were both extended, requiring the blasting of the existing end walls. The drilling, blasting and excavating of the underground system had to be done without damage to existing underground chambers and tunnels, or any of the existing structures, equipment or instrumentation facilities, often within just a few feet of the blasting. This required careful control of vibrations, airblast overpressures and dust. Because the only available non-electric detonating systems were found to be unreliable and unsafe, electric systems would be preferred if they could be used in a safe manner at this site. High electrical potentials existed at the site, and the facilities could not be shut down. Electrical fields were studied carefully, both in the underground environment and above the ground surface. Based on these results, it was concluded that electric detonators could be used if special blasting procedures were developed and followed. In accord with contracting practices of this Spanish agency, the contract was not awarded to the lowest bidder, but to the bidder who demonstrated the best understanding of the project and who presented the best technical proposal for conducting the work to a conclusion that would be satisfactory to the owner. The development of the technical proposal was a two-month effort for a technical group and support staff, prepared in Madrid.

• OSTI ID: 469026
• Report Number(s): CONF-970224--
• Country of Publication: United States
• Language: English

Related Subjects

13 HYDRO ENERGY
EXPANSION
EXPLOSIVE FRACTURING
HYDROELECTRIC POWER PLANTS
MODIFICATIONS
UNDERGROUND FACILITIES