Pergau Hydroelectric Project, Malaysia: Excavation of the Inclined Pressure Shaft

摘要

Inclined shafts, be they for mines or civil projects, are relatively rare. Vertical shafts generally hold the economic advantage because they are technically less demanding and can be constructed more quickly. Occasionally, however, particular circumstances tip the balance towards an incline, as they did for the pressure shaft at the Pergau hydroelectric project in Malaysia. The contractor's experiences in the construction of the inclined shaft at Pergau are reported and it is hoped that the account will assist those who are faced with planning this difficult operation in future. The Pergau hydroelectric project is located in the state of Kelantan in the northeast of Malaysia. It will be capable of generating 600 MW. The main elements of the scheme include a 2 500 000 m~3 earthfill dam, more than 4 km of steel and concrete-lined pressure conduit, 23 km of aqueduct tunnel, an underground powerhouse with more than 2 km of associated access and utility tunnels, 50 km of roads and 80 km of transmission line. The owner of the station is Tenaga Nasional Bhd (TNB), the privatized Malaysian power utility. The owner's supervising engineer for the construction was the Snowy Mountains Engineering Corporation of Australia (SMEC). The construction costs were more than $US700M, of which approximately $US400M was for the civil engineering work. The design-and-build contractor for the scheme was KBBC Sdn Bhd, a joint venture of Kerjaya of Malaysia and Balfour Beatty and Cementation (now Kvaerner) of the United Kingdom. The design subcontractor was Knight Piesold of the United Kingdom and the electrical and mechanical elements of the work were undertaken by GEC Alsthom, a Franco-British company. Construction started in 1991 and the civil work was completed in 1996. Electrical and mechanical installation continued into 1997 and the station was ready for commissioning at the beginning of 1998.