Profile: 

The project is a subsea tunnel. It used the slurry balanced HK TBM with the diameter of 7.02 meters. The formation is 140-160MPa weakly weathered granite.

Difficulty: 

The common disc cutter has a short service life during the construction. It only advanced 15-18 meters with the wear of 10mm on the edge disc cutters. The cutter change frequency is high.

Measures and effects: 

We recommended HD TCI disc cutter with more teeth, thanks to which the cutter change frequency was greatly lowered, and 45 meters was excavated with the wear of 3mm on the edge disc cutters.

 Description on the use of East heavy-duty flat-teeth cutters

Common cutter rings were found poor wear resistance when the slurry TBM of our project advanced to weakly weathered granodiorite (about 160MPa) . Take traces of 46A and 46B in the outmost side of the edge cutters for example, the average service life of the rings was only 8-10 rings (wear of 9mm).

Then EAST's heavy-duty flat cutters were used, and the service life of the cutters along traces of 46A and 46B was increased to about 45 rings (1.5 meters/ring), about 4.5 times of common cutter rings, thus reducing the replacement times, enhancing the boring efficiency, and cutting down the cutter consumption.

China Railway First Group Co., Ltd

Management Department of Xiamen Metro Line 3 Xiang’an to Bendao Cross-sea Channel Second Work Area Project

2019.1.8

January 8, 2019