Design of the power caverns for Pergau hydroelectric project, Malaysia

摘要

A power-generation cavern of 30-m span has beenbuilt in hydrothermally altered granite rock at the Pergauhydroelectric project in northern Malaysia. One implication of thefast-track design-and-build nature of the project was that theadditional site investigation that was needed to provide specificdata for the design had to be undertaken during the early part ofthe construction work. This execution of the design andconstruction work in tandem bed a major influence on the way inwhich the design developed and on the design decisions that had to de made.The development of the design is described, from the initialanalysis, in which relatively simple numerical programs andlimited geotechnical data were employed, to the detailed analyses,in which, principally, the computer program UDEC was usedtogether with discontinuity data acquired during the earlyconstruction phases of the project. The intersection of largefissures containing hot water and hydrothermally altered rock hadnot been predicted from the site investigation undertaken for theproject and the solutions that were engineered for theseunanticipated ground conditions are explained.