The test excavation by the Rock Tunneling Machine in Konoura Tunnel, Hokuriku Main Line, J. N. R.

Abstract

We used tentatively a Rock Tunneling Machine on the bottom drift of Konoura Tunnel in Japanese National Railways (double track railway tunnel).
The purposes of the test were the evaluation of suitability of the machine against geological condition and investigation of economical advantage of machine tunneling method.
Rocks in the tunnel are mudstone and tuffacious mudstone which belong to Miocene, Tertiary, and then those compressive strength are 80 to 130kg/cm² and those seismic speeds at the site are 1.8 to 2.2km/sec.
The machine (bore diameter 2.3m) was Robbins type and was being built in the Komatsu Mfg. Co. it was successful on the test excavation. The total length of the excavating by the machine were 987.6m and rates of advance were 24.6m/day at maximum and approximately 350 m/month in average.
This paper describes that:
(1) Relation between cutter type and rock properties.
(2) Relation between advance of excavation and rock properties.
(3) Deformation of ground and surface of the drift after excavation on the machine and ordinary tunneling method.