Working Program for Shallow Borehole Investigations

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後藤 淳一; 池田 幸喜; 熊崎 直樹; 向井 圭; 岩月 輝希  ; 濱 克宏 

not registered; Ikeda, Koki; Kumazaki, Naoki; Mukai, Kei; Iwatsuki, Teruki; Hama, Katsuhiro

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he MIU project has been conducted at the Shobasama site since 1997. JNC decided to shift the construction site for the underground research laboratory to the Mizunami city's property at Togari/Yamanouchi in 2001. The contract to lease the land was signed in January of 2002, and the investigations from surface have now started. In the revised general plan for the geoscientific research programme of the MIU project (JNC, 2002), investigations are conducted in three phases, Phase 1 surface-based investigations, Phase 2 during excavation of shafts and experimental tunnels and Phase 3 the underground operations. Overall objectives of the project are: To develop basic techniques to investigate, analyse and evaluate the deep geological environment, and To develop basic engineering techniques for use in the deep underground. Objectives of phase 1, surface-based investigations are: To construct a geological model based on the investigation from surface and understand the deep geological environment before excavation of the shaft and experimental drifts, To develop the detailed design and construction plan of the shaft and experimental drifts, and To develop scientific plans for Phase 2, investigations during excavation of the shaft and experimental drifts. In the MIU project and the Regional Hydrogeological Study(RHS), a large surface-based study surrounding the MIU, three scales of investigation are employed They are: Regional scale(several 10km square), Local scale(several km square), and Block scale(several 100m square). Investigations in the MIU project are, for the most part, perfomed at the block scale while those in the Regional Hydrogeological Study (RHS) project are performed at the regional and local scales. The Phase 1 surface-based investigations are planned for completion by the end of 2004, while excavation of the main shaft is planned to start within the fiscal year of 2003. The Shallow Borehole Investigations are one of the first programmes, together with the