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Cutting Performance of Shield Cutters in Soft Rock
(1 State Key Laboratory of High Performance Complex Manufacturing, Central South University, Changsha 410083; 2 College of Mechanical and Electrical Engineering, Central South University, Changsha Hunan 410083; 3 School of Mechanical Engineering, Xiangtan University, Xiangtan 411105)
Abstract Based on the rational simplification of the cutting process of shield cutters in soft rock, this paper establishes a 2D numerical model using the particle discrete element method; analyzes a dynamic cutting process; and studies the influence of the rake angle, cutting depth and rock joint on the rock-breaking performance of shield cutters. The results show that cutting the soft rock is a process of "extruding and then tensioning." The force application point of a cutter is gradually shifted from the tip of the cutter to the front edge of the cutter, and then back to the tip of the cutter with variations of the cutting stroke, which is consistent with the change of the cutter force. With the increase of the cutter's rake angle and cutting depth, the broken rock block increases while the specific energy consumption decreases. The rock-breaking modes of the cutter are different under different joint dip angles, and because of more easily forming the broken rock block the rock-breaking efficiency is higher under a joint angle of less than 90° than a joint angle of more than or equal to 90°. The experiments show that the actual process of rock breaking and the force applied on the cutter agree well with those determined via numerical simulation.
Abstract：
Based on the rational simplification of the cutting process of shield cutters in soft rock, this paper establishes a 2D numerical model using the particle discrete element method; analyzes a dynamic cutting process; and studies the influence of the rake angle, cutting depth and rock joint on the rock-breaking performance of shield cutters. The results show that cutting the soft rock is a process of "extruding and then tensioning." The force application point of a cutter is gradually shifted from the tip of the cutter to the front edge of the cutter, and then back to the tip of the cutter with variations of the cutting stroke, which is consistent with the change of the cutter force. With the increase of the cutter's rake angle and cutting depth, the broken rock block increases while the specific energy consumption decreases. The rock-breaking modes of the cutter are different under different joint dip angles, and because of more easily forming the broken rock block the rock-breaking efficiency is higher under a joint angle of less than 90° than a joint angle of more than or equal to 90°. The experiments show that the actual process of rock breaking and the force applied on the cutter agree well with those determined via numerical simulation.
2015, Vol. 52 