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Study on Cutting Performance of New Wedge-flat Combined TBM Cutters in Extreme Hard Rocks
(1. School of Construction Machinery, Chang'an University, Xi'an 710064; 2. China Communications Construction Central South Engineering Bureau Co., Ltd., Changsha 410116; 3. School of Highway, Chang'an University, Xi'an 710064)
Abstract In response to the characteristic that flat type cutters of full-face rock tunnel boring machines (TBMs) have low rock-breaking efficiency but are wear-resistant in extreme hard rocks, and wedge type cutters have high rock-breaking efficiency but are prone to wear, a new wedge-flat combined cutter was proposed and the influence of cutting ring structure on rock breaking and wear were explored. Firstly, uniaxial compression, Brazilian splitting,and small-scale linear cutting tests and simulations were conducted on extremely hard diorite (exceeding 230 MPa)collected from a tunnel project to verify the accuracy of the numerical methods. Then, considering the influences of the width ratio of wedge ring segment to flat ring segment and the number of wedge or flat ring segments, full-scale numerical simulations for linear rock breaking were performed in sequence to study the change rules of rock-breaking normal force, rolling force, specific energy, and specific wear work. Research results indicate that the rock breaking load of the wedge-flat combined rings exhibited a clear multi-stage fluctuation pattern, and the load of the flat ring segment was significantly greater than that of the wedge ring segment; The ratio of wedge ring width to flat ring width had a significant impact on rock-breaking load, efficiency, and cutter ring wear, while the effect of the number of wedge or flat ring segments was not significant; It is recommended to set the width ratio of the wedge ring segment to flat ring segment to 0.5 to balance efficient rock breaking and wear resistance, and set the number of wedge or flat segments to 4 or 6.
Abstract：
In response to the characteristic that flat type cutters of full-face rock tunnel boring machines (TBMs) have low rock-breaking efficiency but are wear-resistant in extreme hard rocks, and wedge type cutters have high rock-breaking efficiency but are prone to wear, a new wedge-flat combined cutter was proposed and the influence of cutting ring structure on rock breaking and wear were explored. Firstly, uniaxial compression, Brazilian splitting,and small-scale linear cutting tests and simulations were conducted on extremely hard diorite (exceeding 230 MPa)collected from a tunnel project to verify the accuracy of the numerical methods. Then, considering the influences of the width ratio of wedge ring segment to flat ring segment and the number of wedge or flat ring segments, full-scale numerical simulations for linear rock breaking were performed in sequence to study the change rules of rock-breaking normal force, rolling force, specific energy, and specific wear work. Research results indicate that the rock breaking load of the wedge-flat combined rings exhibited a clear multi-stage fluctuation pattern, and the load of the flat ring segment was significantly greater than that of the wedge ring segment; The ratio of wedge ring width to flat ring width had a significant impact on rock-breaking load, efficiency, and cutter ring wear, while the effect of the number of wedge or flat ring segments was not significant; It is recommended to set the width ratio of the wedge ring segment to flat ring segment to 0.5 to balance efficient rock breaking and wear resistance, and set the number of wedge or flat segments to 4 or 6.
GENG Qi1 HUANG Dengxia2 CHEN Jianxun3 LIU Weiwei3 LUO Yanbin3 MA Maoxun1 LI Xiaobin1
.Study on Cutting Performance of New Wedge-flat Combined TBM Cutters in Extreme Hard Rocks[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(1): 114-124
2025, Vol. 62 