Study on the Mechanism of the Unsaturated Zone in Rock Mass

Sugita, Yutaka; Kikuchi, Hirohito*; Komatsu, Mitsuru*; Nishigaki, Makoto*; Akagi, Yosuke*

JNC TY8400 2003-011, 143 Pages, 2002/02

JNC-TY8400-2003-011.pdf:4.19MB

In geological disposal of high-level radioactive waste (HLW), unsaturated zone will be expected to appear around the disposal tunnel due to the construction of the tunnel. Cooperative research between JNC and Okayama University has done to understand the mechanism of the unsaturation process and the re-saturation process around the tunnel from FY1998 to FY2000.Characterizing Laboratory test on Unsaturated zonE (CLUE) of JNC was used to simulate the unsaturation process, and the piezometer and frequency domain reflectometry (FDR) of Okayama University were used to measure the unsaturation behavior of the CLUE.During this study, the laboratory experiments were performed and the saturation-unsaturation hydraulic characteristics of the material were obtained. The applicability of the FDR to measure the unsaturation condition was examined. Unsaturation hydraulic analysis technique was also applied.These studies supplied the fundamental data on unsaturation processes around the tunnel.