Study on Eccentric Wear Mechanism of Pick-Shaped Cutter in Soft and Hard Interbedded Formation Tunnel

This paper analyzes the stress of the pick-shaped cutter of rotary cutting machine in process of tunnel excavation in soft and hard interbedded formation, results show that the resistance of pick is obviously jumping fluctuations comparing to that of homogeneous formation. When pick transits from cutting hard rock to soft rock, cutting resistance and driving resistance of pick decrease instantaneously, which leads to momentary decreasing of rotation torque. And mud ball is compacted by high impact force of rotary cutting machine when cutting hard rock strata, as a consequence, resistance torque increases. When the sum of resistance torque and starting torque is greater than rotation torque, pick can`t rotate, leading to eccentric wear of pick. At last, this paper puts forward several improvement suggestions.