Cutting Tool Advancements for long Tunnel Drives and Geologic Extremes

Quelle/credit (2): Robbins

The first disc cutters, just 11.5 inches in diameter, were produced by
Robbins for the Humber River Sewer Tunnel TBM in 1956

Quelle/credit (2): Robbins

Larger diameter cutters have become the industry standard in recent decades because of their increased wear volume and longer cutter life in hard rock conditions

$The Robbins Main Beam machine that bored Norway’s Røssåga HEPP was a testing ground for XHD (Extra Heavy Duty) cutter rings that could bore through massive hard rock with minimal fracture zones. Use of the XHD discs resulted in at least 25 % improvement in performance in very hard sections of rock$ Quelle/credit: Robbins

The Robbins Main Beam machine that bored Norway’s Røssåga HEPP was a testing ground for XHD (Extra Heavy Duty) cutter rings that could bore through massive hard rock with minimal fracture zones. Use of the XHD discs resulted in at least 25 % improvement in performance in very hard sections of rock

Quelle/credit: Robbins

Quelle/credit (3): Robbins

Pressure compensating disc cutters were bench tested by Robbins up to 34 bar, and are being used on the Single Shield machine for New York’s Delaware Aqueduct Repair, where pressures up to 20 bar are expected

Quelle/credit (3): Robbins

Diagram of the wireless SmartCutter system for remote disc cutter monitoring

SmartCutter utilizes an electronic sensor that mounts onto each cutter wedge bolt. The sensor transmits data to a receiver in the cutterhead. It measures several variables including vibration, temperature and rotation

Quelle/credit: Robbins

Results from SmartCutter testing at India’s AMR project show that the SmartCutter system accurately monitors cutter wear

Quelle/credit: Robbins

Extreme tunneling conditions call for the most robust TBM cutting tools possible—whether that includes hard and abrasive rock, long-distance tunnels of 15 km or more, or high water pressures. Extreme conditions can be defined as those conditions that result in poor advance rate, catastrophic disc cutter failure, or unacceptable wear life of a disc cutter. While disc cutters are widely considered a mature technology,
there is room for growth and development, spurred on by increasing numbers of projects in difficult ground.

At China’s Yin Han Ji Wei project for example, hard rock, combined with face collapses, damaged cutters and prompted engineers to design a more robust cutter ring to survive in the most severe conditions. It is not just hard rock prompting design changes: at New York, USA’s Delaware Aqueduct Repair, a Single Shield TBM is boring in rock with water pressures up to 20 bar. The 19-inch diameter disc cutters utilize a pressure compensation mechanism that has been bench-tested up to 34 bar in order to excavate under the high pressures. These are just a few of the developments currently being tested...