Horonobe Underground Research Laboratory Project Investigation Program for the 2005 Fiscal Year (2005/2006)

Hama, Katsuhiro ; Seya, Masami; Yamaguchi, Takehiro

The Horonobe Underground Research Laboratory Project is planned to extend over 20 years. Investigations will be conducted in three phases, namely from the surface (Phase 1), during construction of the underground facility (Phase 2) and in the underground facility itself (Phase 3). The 2005 fiscal year is the sixth (and final) year of the Phase 1 investigations and the first year of the Phase 2 investigations.Geophysical, geological, surface hydrogeological and borehole investigations are being carried out in order to develop techniques for exploring the geological environment. Based on the acquired data, geoscientific models are being constructed, revised and verified.As part of the development of techniques for monitoring the geological environment, long-term monitoring of groundwater pressures is ongoing in a borehole equipped in a previous investigation phase. Long-term monitoring systems are also being installed in the remaining boreholes at the site and measurements are ongoing. A remotely operated monitoring system (ACROSS) is also being installed and tested. Studies on the long-term stability of the geological environment include monitoring with seismographs, GPS and electromagnetic surveys. Engineering techniques for application in the deep underground environment will be developed during construction of the underground facilities. To provide input for detailed planning of the Phase 2 and 3 investigations, laboratory tests are being carried out on tunnel reinforcement materials. With a view to improving their reliability, safety assessment methods are being examined using field and laboratory data. Construction of the surface facilities, initiated in the previous fiscal year, is ongoing and the work on the public exhibition hall has now started. Environmental monitoring is ongoing, as is collaboration with domestic and overseas research institutes.