Evaluation of deep shaft excavation with computerized construction; Horonobe Underground Research Laboratory, Underground Research Facilities Project (2nd Period)

Fujita, Tomoo ; Aoyagi, Kazuhei  ; Nago, Makito*

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.