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Sato, Toshinori; Mikake, Shinichiro; Miura, Norihiko*; Ishida, Tomoko*
Tonneru To Chika, 46(12), p.901 - 911, 2015/12
The Japan Atomic Energy Agency conducts studies and research associated with the excavation of underground research facility at the Mizunami Underground Research Laboratory in Mizunami City, Gifu Prefecture. The research laboratory is an underground facility consisting of two shafts and some drifts and excavation has currently extended to a depth of 500 m. One of in-situ experiments, groundwater recovery experiment to understand groundwater pressure and geochemical properties change due to groundwater flooded has been performed in the GL.-500m drift. This report contains the results of design work of concrete plug for groundwater recovery experiment. Structural analysis and thermal stress analysis were performed to check resistant ability to over 5 MPa. Measurement plan was also discussed in this report.
Fujita, Tomoo; Aoyagi, Kazuhei; Nago, Makito*
Tonneru To Chika, 46(7), p.481 - 489, 2015/07
The Japan Atomic Energy Agency (a National Research and Development Agency) is constructing shafts and research tunnels in Horonobe-cho, Teshio-gun, Hokkaido as part of the Horonobe Underground Research Project. This report summarizes investigations into computerized construction while excavating the shaft for the Horonobe Underground Research Centre. Cracking in the lining concrete occurred due to the development of rock spalling near the wall surface while excavating the ventilation shaft. To that end, we created a flowchart to select kinds of shaft supports for use in subsequent works that took steps appropriate for the bedrock collapse phenomenon during excavating, countermeasures for this and extent of spalling. In addition, this report contains information on pre-grouting works on the fault zone and its results which were conducted as a measure against groundwater inflow which can be a problem during excavating works and also the results of these works.
Sato, Toshinori; Mikake, Shinichiro; Noda, Masaru*; Kobayashi, Shinji*
Tonneru To Chika, 45(7), p.501 - 510, 2014/07
The Japan Atomic Energy Agency conducts studies and research associated with the excavation of underground research facility at the Mizunami Underground Research Laboratory in Mizunami City, Gifu Prefecture. The research laboratory is an underground facility consisting of two shafts and some drifts and excavation has currently extended to a depth of 500 m. This report contains the evaluation results of measures to control the welling of water and measures to prevent ground collapse based on construction records up to now. For measures to control the welling of water, we carried out pre-grouting from umbrella-shaped grouthing holes placed at the bottom of the shaft and observed improvements in given permeability. For measures to prevent ground collapse, we conducted safe shaft sinking along faults by combining reinforecement works using rock bolts and fore-poling works using silica-resin grouting. Both measures were conducted using a shaft sinking drill carriage "Shaft Jumbo" that made it possible to efficiently incorporate short step shaft sinking cycles.
Kaneda, Tsutomu*
Tonneru To Chika, 40(2), p.148 - 149, 2009/02
An overview of the directional control borehole drilling applied to the MIZ-1 borehole drilling at the Mizunami Underground Research Laboratory is described as an example of the control borehole drilling reamed with outer casing.