地应力作用下隧道爆破周边孔参数优化研究

为探究在地应力作用下隧道爆破时周边孔最优参数,以白竹山隧道为工程背景,通过数值模拟方法研究当隧道地应力为5 MPa时的情况,将周边孔不耦合装药系数和空气间隔装药段数进行调整,确定合理的爆破参数指导现场施工。研究表明,在相同药量情况下,当不耦合系数为1.4时,粉碎区范围适中,岩体破碎充分,炮孔之间形成良好贯通;周边孔采用空气间隔装药时,孔底空气长度为0.6 m,每节药卷为0.3 m的4段间隔装药结构较为合适,能将平均超欠挖厚度控制在20 cm内,爆破效果较好。

In order to explore the optimal parameters of periphery holes during tunnel blasting under ground stress,taking Baizhushan Tunnel as the engineering background,when the ground stress of Baizhushan Tunnel is 5 MPa,the decoupling charge coefficient of periphery holes and the number of air interval charge sections are adjusted to determine reasonable blasting parameters to guide on-site construction.The study shows that in the case of the same charge quantity,when the uncoupling coefficient is 1.4,the range of the crushing area is moderate,the rock mass is fully broken,and a good connection is formed between the blast holes;when the air interval charge is used in the periphery hole,the air length at the bottom of the hole is 0.6 m,and the 4-section interval charge structure of 0.3 m per charge roll is more suitable;the average overbreak and underexcavation thickness can be controlled within 20 cm,and the blasting effect is better.