Progress of shaft construcion and cycle time analysis in the Horonobe Underground Research Laboratory Project

Yamazaki, Masanao; Sekiya, Yoshitomo; Fujikawa, Daisuke; Kitagawa, Yoshito*

The shafts and drifts of the Horonobe Underground Research Laboratory Project have been constructed by JAEA. The construction method of shaft is a short step method. The East Shaft of excavation system is the blasting excavation, and the Ventilation Shaft is the machine excavation. At the present, The East Shaft has ended to G.L.-140.5 m and Ventilation Shaft has ended to G.L.-210.5 m at the end of July, 2008. The difference in depth change or a excavation system was analyzed about the excavation time which occupies about 40% of the cycle time of each shaft. This paper reports the outline of the construction track record of the shafts and the result of having analyzed cycle time paying attention to excavation time.