General Report

This report presents an overview of geotechnical investigations of dam sites, which are to consist of exploration, testing, idealization, and analysis, and provide design recommendations. The idealization to which both geologists and engineers contribute form the basis for all sub-sequent studies. A dam site is to be characterized in geotechnical terms during early phases of the investigation. Testing, particularly in-situ testing, has to be related to natural conditions, with results meeting requirements of analysis and design. Parametric studies are to assess the design consequences of geotechnical parameters. Rock classification contributes only if keyed to design decisions or construction aspects. In concluding two specific concerns are raised, rock as affected by construction procedures such as blasting, and the erosion of rock masses, e. g. by spillway operation, with both topics to warrant very close attention by the geotechnical profession active in hydropower engineering. In specialists' meetings problems and failures should more freely be discussed in order to advance the contribution of rock mechanics to dam design.