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Ishii, Yoji; Watanabe, Kazuhiko; Kamiya, Akira; Hayano, Akira; Mikake, Shinichiro; Takeuchi, Shinji; Ikeda, Koki; Yamamoto, Masaru; Sugihara, Kozo
JAEA-Technology 2010-044, 92 Pages, 2011/02
JAEA-Technology-2010-044.pdf:11.73MB
The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the ventilation shaft. During this investigation, a zone with high hydraulic head and low hydraulic conductivity was observed at around GL-400m. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the Ventilation Shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.
Ishii, Yoji; Mikake, Shinichiro; Kamiya, Akira; Watanabe, Kazuhiko; Nobuto, Jun*; Kusano, Takashi*
Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.185 - 190, 2011/01
The "Mizunami Underground Research Laboratory" has been carrying out scientific research in granite to establish the technological basis for high-level radioactive waste disposal. To get reliable information on the rock mass geology and hydrogeology and on the bedrock conditions, a pilot borehole investigation was carried out before sinking the Ventilation Shaft. A region with high hydraulic head and low hydraulic conductivity was intersected by the pilot borehole at around GL-400m during these investigations. To reduce water inflow during excavation, pre-excavation grouting with micro-fine cement was done in this region before sinking the ventilation shaft. Despite the high hydraulic head and the low hydraulic conductivity, effective reduction of water-inflow was achieved.
Nobuto, Jun*; Tsuji, Masakuni*; Kusano, Takashi*; Mikake, Shinichiro; Kamiya, Akira; Ishii, Yoji
Dai-40-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.179 - 184, 2011/01
At Mizunami Underground Research Laboratory, the water inflow should be minimized, considering water treatment expense. Although cement grout has been applied to reduce water inflow up to 460 m depth, water inflow through small fractures which cement grout cannot penetrate can not be neglected at deeper underground. Liquid-type grout which has high durability as well as good penetrability was therefore tested at the depth of 300 m. Test results indicated that liquid-type grout could sufficiently reduce hydraulic conductivity of rock mass with less than 1Lu, and could keep improvement effect even after applied water pressure of more than 9 MPa was applied.
Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Sugihara, Kozo; Takeuchi, Shinji; Hayano, Akira; Sato, Toshinori; Takeda, Shinichi; Ishii, Yoji; Ishida, Hideaki; et al.
JAEA-Technology 2010-026, 146 Pages, 2010/08
JAEA-Technology-2010-026.pdf:41.08MB
JAEA-Technology-2010-026-appendix(CD-ROM).zip:83.37MB
The Mizunami Underground Research Laboratory (MIU), one of the main facilities in Japan for research and development of the technology for high-level radioactive waste disposal, is under construction in Mizunami City. In planning the construction, it was necessary to get reliable information on the bedrock conditions, specifically the rock mass stability and hydrogeology. Therefore, borehole investigations were conducted before excavations started. The results indicated that large water inflow could be expected during the excavation around the Ventilation Shaft at GL-200m and GL-300m Access/Research Gallery. In order to reduce water inflow, pre-excavation grouting was conducted before excavation of shafts and research tunnels. Grouting is the injection of material such as cement into a rock mass to stabilize and seal the rock. This report describes the knowledge and lessons learned during the planning and conducting of pre-excavation grouting.
Mikake, Shinichiro; Yamamoto, Masaru; Ikeda, Koki; Kamia, Akira; Kinoshita, Harunobu; Ishida, Hideaki; Ishii, Yoji
no journal, ,
no abstracts in English
Hirano, Toru; Ishii, Yoji; Matsui, Hiroya
no journal, ,
no abstracts in English
Asai, Hideaki; Matsui, Hiroya; Mikake, Shinichiro; Ito, Hiroaki; Horiuchi, Yasuharu; Ishii, Yoji
no journal, ,
The Mizunami Underground Research Laboratory (MIU) is currently being constructed by Japan Atomic Energy Agency. As part of MIU Project, development of engineering technology for deep underground intended for the crystalline rock is executed. The research to confirm the effectiveness of engineering technology is being executed during its excavation now. It reports on study results up to 300m in depth of engineering technology research and the schedule for the future.
Matsui, Hiroya; Mikake, Shinichiro; Asai, Hideaki; Ishii, Yoji; Horiuchi, Yasuharu; Kumada, Koji
no journal, ,
The Mizunami Underground Research Laboratory (MIU) of the Japan Atomic Energy Agency is a major site for geoscientific research to advance the scientific and technological basis for geological disposal of high-level radioactive waste in crystalline rock. Studies on relevant engineering technologies in the MIU consist of research on design and construction technology for very deep underground applications, and engineering technology as a basis of geological disposal. In the Second Phase of the MIU project, engineering studies have focused on research into design and construction technologies for deep underground. The main subjects in the study of very deep underground structures consist of the following: Demonstration of the design methodology, Demonstration of existing and supplementary excavation methods, Demonstration of countermeasures during excavation and Demonstration of safe construction. This poster show the main topics and results of the study until FY2009.
Mikake, Shinichiro; Ishii, Yoji; Ikeda, Koki; Yamamoto, Masaru
no journal, ,
JAEA's task is to provide the scientific and technical basis for safe geological disposal of high-level radioactive waste. This involves researches on development and improvement of techniques for characterization of the deep geological environment and a wide range of engineering for deep underground application in crystalline rock at "Mizunami Underground Research Laboratory (MIU)". MIU is currently being constructed. The Main and Ventilation Shafts had reached GL-460m. This report describes the summary of construction.