Abstract
The basic excavation methods to be used in the New Tomei Expressway tunnels are the method of upper heading and bench in locations where the ground is relatively good, and the method of upper heading and bench with a center pilot in the upper heading in locations where face stability is poor.
In addition to these excavation methods, the TBM Pilot and Enlargement Excavation Method is to be introduced as a new excavation method for the New Tomei Expressway tunnels. With the TBM Pilot and Enlargement Excavation Method, by performing a pilot excavation by TBM within the tunnel cross section in advance, various beneficial effects such as confirmation of geological conditions and drainage into the pilot are expected, so that safe and efficient enlargement excavation can be performed.
This paper describes evaluation of beneficial effects for the TBM Pilot and Enlargement Excavation Method in large scale tunnels.
