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Study on Rock Breaking Mechanism of Undercutting Cutter at Precut Slot on
Free Surface
(1. Fengyang Yongcheng Coal Mine of Dengfeng Coal Industry Co., Ltd of CYMG, Dengfeng 452470; 2. CYMG Luoyang Coal Industry Region Management Company, Luoyang 471023; 3. School of Mechanical and Electrical Engineering, China University of Mining and Technology, Xuzhou 221116)
Abstract In order to enhance the performance of undercutting cutter in breaking hard rock and reduce rock breaking
load, the numerical model for hard rock breaking by undercutting cutter at precut slot has been created to investigate how various combinations of cutting thickness values and slotting parameters (slot spacing, slot depth) will affect the rock breaking performance of undercutting cutter, and the mechanism by which precut slot affects the rock breaking process of undercutting cutter has been revealed. As the study results indicate, when the slot spacing is equal to the cutter diameter, the rock with precut slot can be equivalent to a rock with unconfined compression, and the cutting force is reduced by over 30% as compared with cutting an unslotted rock. Besides, the matching relation between cutting thickness of undercutting cutter and slot spacing will significantly affect the specific energy of rock breaking. To achieve the optimum specific energy of rock breaking, the cutting depth and slot spacing are 20 mm and 100 mm respectively. In addition, the relation between fractal dimension of rock debris and specific energy of rock breaking has been established, i.e. the specific energy consumption increases linearly as the fractal dimension increases
Abstract：
In order to enhance the performance of undercutting cutter in breaking hard rock and reduce rock breaking
load, the numerical model for hard rock breaking by undercutting cutter at precut slot has been created to investigate how various combinations of cutting thickness values and slotting parameters (slot spacing, slot depth) will affect the rock breaking performance of undercutting cutter, and the mechanism by which precut slot affects the rock breaking process of undercutting cutter has been revealed. As the study results indicate, when the slot spacing is equal to the cutter diameter, the rock with precut slot can be equivalent to a rock with unconfined compression, and the cutting force is reduced by over 30% as compared with cutting an unslotted rock. Besides, the matching relation between cutting thickness of undercutting cutter and slot spacing will significantly affect the specific energy of rock breaking. To achieve the optimum specific energy of rock breaking, the cutting depth and slot spacing are 20 mm and 100 mm respectively. In addition, the relation between fractal dimension of rock debris and specific energy of rock breaking has been established, i.e. the specific energy consumption increases linearly as the fractal dimension increases
ZHANG Qin1 SU Jinhua2 LI Aijun1 XU Binbin1 YAN Xiaolei1 LIU Ding1 YANG Junqi1TANG Jintao1 LI Hongsheng3
.Study on Rock Breaking Mechanism of Undercutting Cutter at Precut Slot on
Free Surface[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(6): 192-198
2023, Vol. 60 