Retrospective case example using a comprehensive suitability index (CSI) for siting the Shisan-Ling power station, China

The purpose of this paper is to present a retrospective case example of usi ng the rock engineering systems (RES) methodology to site a pumped storage power station in China. With such a siting problem, there are many interact ing factors governing both the site and the specific underground position o f the powerhouse. The RES approach, based on an interaction matrix for semi quantitative characterization of the factors and their interactions, is use d to develop a comprehensive suitability index (CSI). In this way, the fact ors governing the geological and rock mechanics related factors are structu red and evaluated. Additionally, the complexity of the decision making proc ess is condensed to the CSI values for different potential sites and underg round locations, a higher CSI value indicating a more suitable site. The retrospective analysis uses information from the investigations made du ring the actual site investigation and design work for the Shisan-Ling Powe r Station, China - which has been constructed. For the first stage, site se lection for the overall engineering arrangement, 11 parameters concerned wi th geology, geomorphology, engineering layout, environment, cost and constr uction are taken into account. After comparison of site options in conglome rate, andesite and limestone formations, the conglomerate formation proved to be most favorable - because it has the highest CSI value. For the second stage, specifically locating the underground powerhouse, another seven par ameters associated with faults, joints, groundwater, etc, are evaluated. As a result, position II proved to be the most favorable location for the pow erhouse. Since these were the same conclusions reached during the actual in vestigations, this retrospective application of the CSI demonstrates the va lue of the RES methodology and associated indices for assisting in rock eng ineering design. (C) 2000 Elsevier Science Ltd. All rights reserved.