2023 Volume 65 Issue 4 Pages 341-348
In tunnelling projects characterized by significant overburden and limited pre-excavation ground information, maximizing the utilization of geotechnical information acquired during the excavation process emerges crucial. Currently, construction is underway for a 25-kilometer-long tunnel as part of the Chuo Shinkansen, which traverses beneath the Akaishi Mountains in central Japan, reaching depths of up to 1400 meters. To effectively handle the diverse geological and groundwater conditions encountered, a specific excavation procedure has been implemented. This procedure combines the use of extra-long range controlled boring, reaching horizontally as far as 1000 meters, with displacement monitoring of the excavated tunnel. Thus far, this approach has proven effective in ensuring safe and rational excavation operations under high overburden conditions.
