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Study on the Blasting Effect of Tunnel Wedge Cut under Different Cut Hole Angles
(1. YCIH Mining Engineering Co., Ltd., Kunming 650217;2.Faculty of Electric Power Engineering, Kunming University of Science and Technology, Kunming 650500)
Abstract The cut hole angle is a key parameter influencing the blasting effect of wedge-shaped cuts. To determine the optimal cut hole angle and improve the cavity formation and tunnel excavation efficiency, this study takes the Gonghecun Tunnel on the Ludian-Qiaojia Expressway in Yunnan as the engineering background. Mechanical tests were first conducted on rock samples collected from the blasting area. Then, numerical simulations of different cut hole angles were carried out using the Smoothed Particle Hydrodynamics (SPH) method, and the results were verified through field tests. The results indicate that as the cut hole angle increases from 55° to 75°, the effective stress within the cavity significantly increases by up to 108%. Simultaneously, the damage zone around the hole opening expands from 0.2 m to 0.9 m. The maximum ejection velocity first decreases and then increases: from 43.6 m/s at55°, it drops to 36.3 m/s at 65°, then rises to 43.1 m/s at 75°, with corresponding variations in ejection distance.Therefore, a larger cut hole angle enhances both effective stress and the surrounding rock damage zone. Among the tested angles, 65° yields the best cavity formation effect. Field tests showed good agreement with the simulation results, verifying the effectiveness of the numerical model.
Abstract：
The cut hole angle is a key parameter influencing the blasting effect of wedge-shaped cuts. To determine the optimal cut hole angle and improve the cavity formation and tunnel excavation efficiency, this study takes the Gonghecun Tunnel on the Ludian-Qiaojia Expressway in Yunnan as the engineering background. Mechanical tests were first conducted on rock samples collected from the blasting area. Then, numerical simulations of different cut hole angles were carried out using the Smoothed Particle Hydrodynamics (SPH) method, and the results were verified through field tests. The results indicate that as the cut hole angle increases from 55° to 75°, the effective stress within the cavity significantly increases by up to 108%. Simultaneously, the damage zone around the hole opening expands from 0.2 m to 0.9 m. The maximum ejection velocity first decreases and then increases: from 43.6 m/s at55°, it drops to 36.3 m/s at 65°, then rises to 43.1 m/s at 75°, with corresponding variations in ejection distance.Therefore, a larger cut hole angle enhances both effective stress and the surrounding rock damage zone. Among the tested angles, 65° yields the best cavity formation effect. Field tests showed good agreement with the simulation results, verifying the effectiveness of the numerical model.
LI Yuhua1 GAO Yawei ZHONG Qiufeng1 QIN Lixuan2 LI Junjie CHENG Zhiming2 HUANG Yonghui
.Study on the Blasting Effect of Tunnel Wedge Cut under Different Cut Hole Angles[J] MODERN TUNNELLING TECHNOLOGY, 2025,V62(3): 108-116
2025, Vol. 62 