| "Grouting is a procedure to improve the mechanical properties and/or water tightness of dam rock foundations by injecting cement-based grout. At dam sites in Japan, however, foundation grouting has become increasingly difficult due to complex geological conditions, and there are increasing demands for lower-cost public works projects and for conservation of the natural environment. Therefore, we have been working to establish an effective and economical method for dam foundation grouting.Much progress has been made to rationalize grouting, such as mixing and transporting grouts using the centralized plant method and computerizing the grouting operation, but not for rationalizing the grouting work itself. Japanese dam engineers therefore studied reducing the cost of dam foundation grouting by adopting the water pressure test with monotonous pressurization (WPT-MP), which speeds up permeability evaluation during grouting.In this paper, the applicability of WPT-MP is verified at a granodiorite dam foundation by conducting a conventional water pressure test with stepwise pressurization (WPT-SP) and WPT-MP carried out at the same stage. The procedure and the results of verification tests are described, and the results of WPT-MP are reproduced by saturated-unsaturated seepage analysis using the finite element method. Based on these results, precautions for performing water pressure tests (WPT) are discussed." |
