【摘要】 为解决硬岩小断面隧道爆破，因掏槽孔角度设计不合理，导致槽腔岩石破碎效果差，炮孔利用率低等问题，基于楔形掏槽爆破破岩理论，建立楔形掏槽槽腔岩石受力数学模型，推导出槽腔岩体完全破裂、抛掷的力学条件；并结合温州瓯江引水隧洞工程实践，确定既定断面宽度时楔形掏槽最佳布孔角度。研究结果表明：掏槽孔与工作面的夹角宜控制在60°≤θ<90°范围内，当倾角略大于60°时，可为施工预留充足的空间，且炮孔受力满足F_s≥Q_s的条件，岩石向外抛掷彻底；在相同起爆条件下60°布孔方式，所产生的应力波对岩体作用范围更广且更均匀，槽腔底部应力场强度为倾角70°和80°的1.32、1.65倍，有效克服了底部硬岩夹制作用；60°布孔时爆后损伤形态呈“喇叭口”状，形成的槽腔体积更大，X方向岩石破裂面积同比增加9.1%～26.8%,70°、80°布孔Y、Z方向岩石破裂面积与其相比减少约为40.2%、45.4%;现场工业性试验平均进尺增加15.4%,炮孔利用率达92%以上。因此，在硬岩小断面隧道掘进中采用略大于60°掏槽孔布置方式，可有效提高炸药的破岩效率，增加循环进尺，节约了成本，对实际工程应用具有指导意义。更多还原

【Abstract】 To address the blasting of small-section tunnels in hard rock, due to the hollowing hole angle design is unreasonable, resulting in poor crushing effect of the groove cavity rock, low utilization rate of the gun hole and other problems, Based on the theory of wedge hollowing blasting rock breaking, establish a mathematical model of stress distribution in rock within a wedge-shaped excavation cavity, deduce the slot rock body completely broken, throwing mechanical conditions; and combined with the Wenzhou Oujiang diversion tunnel project practice, to determine the established section width wedge hollowing optimal hole layout angle. The results show that: hollowing holes and the working surface of the angle is easy to control in the range of 60°≤θ<90°, when the inclination angle is slightly greater than 60°, can be reserved for the construction of sufficient space, and the force of the hole to meet the conditions of F_s ≥ Q_s, the rock thrown outward thoroughly; in the same conditions of the detonation of the 60° hole, the resulting stress wave on the rock body role of the wider and more uniform, the bottom of the slot cavity stress field strength is tilt angle of 70° and 80° of 1.32, 1.65 times, effectively overcome the bottom of the hard rock entrapment used; 60° hole in the post-blast damage pattern was “trumpet”, the formation of a larger slot volume, X-direction rock rupture area increased by 9.1% to 26.8% year-on-year, 70°, 80° hole in the Y, Z-direction rock The ruptured area of Y and Z direction rocks of 70° and 80° holes is reduced by about 40.2% and 45.4%; the average footage of each gun in the field industrial test is increased by 15.4%, and the utilization rate of the gun holes reaches more than 92%. Therefore, the use of slightly more than 60° hollowing hole arrangement in hard rock small section tunnel boring can effectively improve the explosives rock-breaking efficiency, increase the cycle of footage, cost savings, and the application of the actual engineering arch of guiding significance.更多还原