Development of the observational construction technology in the Horonobe Underground Research Laboratory

Aoyagi, Kazuhei  ; Nago, Makito*

In this paper, we described the development of the supporting tool of observational construction of the underground research laboratory, and the monitoring result of hydro-mechanical properties around the gallery wall. As an observational construction tool, we developed a "3D geological structure/construction data visualization system". The geological data, measurement data, construction data, and prediction analysis results are visualized and integrated comprehensively as the construction proceeds. The planned support pattern was examined according to the visualized data. In addition, the Excavation Damaged Zone (EDZ) was extended within 1.0 m from the gallery wall. In this area, hydraulic conductivity was enhanced. However, the extent of the EDZ was not enlarged along with time; the stability of the support was also confirmed on the basis of the measurement of stress in the shotcrete. Integrating these results the observational construction considering the development of an EDZ can be established. This technology will have an important role in geological disposal of high-level radioactive waste.