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TBM cutter types and mechanism of rock fragmentation

1.1 commonly used type of TBM cutter

Currently used knives generally fall into two categories: scraping cutter, rolling tool
Scraping cutter (cutter bit, scraper)
Scraping cutter refers to not only through the cutterhead rotating rotation of rock cutting tool. There is a huge variety of scraping cutter on the tunnelling boring machine at present commonly used skiving cutter class such as edge scraper, scraper, cutting bit, serrated cutter, pre-cutting bit, copy cutter bit, scraper, etc.
Rolling tool(roller cutter)
Rolling tool refers to not only with the cutting wheel rotation, also as a rotation movement of the rock cutting tool.

According to the blade shape, roller cutter can be divided into: tooth shape roller cutter (steel and ball tooth), disc cutter (steel circle roller cutter and the ball circle roller cutter).
According to the installation position ,roller cutter can be divided into: face roller cutter, center roller cutter, edge roller cutter, reaming roller cutter.

The primarily roller cutter of tunnelling boring machine is single roller cutter double roller cutter and multipoint roller cutter.

1.2 Mechanism of rock fragmentation
The working principle of scraping cutter

Under the action of thrust in cutter head, scraper embedded slag rock or rock, and the cutter head turns cutters scraping rock, constraints in form plows furrows. It is high efficiencial, and the cutter head turning makes a big resistance.In soft soil layer or roller cutter broken through the scraper residue after excavation, the facade with the scraper slag residue in groove. So the scraper has boh the function of cutting and loading.

The working principle of the disc roller cutter

The cutter head in thrust under the action of vertical cylinder, making its disc roller cutter into rock;The cutter head around rotating device driven by a driving gear roller cutter center shaft orbit, and at the same time the roller cutter still around their respective cutter shaft rotating, making the roller cutter continuous rolling on the rock face. Cutter head imposed on cutter ring with thrusting and rolling power (torque), thrusting the cutter ring into rock mass, rolling cutter ring rolling rock mass. Undering the extruding and shearing of roller cutter ,it broken in rock mass and cut out a series of concentric circles on the rockface.