Construction at the Shirokawa Dam on the Excessively Slaked Soft-rock Foundation

Abstract

In the recent development of dam construction, there has been an increasing number of dams constructed on the soft rock foundation formed in or after the Tertiary era. This tendency applies to the construction project of Shirokawa Dam whose site geology is featured by sand and mudstones of Neogene Tertiary cenozoic era. Those stratums are proned to slaking as verified by experimental tests conducted locally at the site and at the laboratory. This report contains the result of case studies on the experimental test method adopted to clarify a more accurate aspect of slaking and the construction method for prevention against possible deterioration of the excavated face of foundation.