Research and application of hard rock deep-hole advance blasting in comprehensive roadway excavation

Deep hole advance blasting technology is adopted for hard rock roadway excavated by comprehensive tunne- ling machine. It can increase the fracture and damage scope of rock mass,and make the comprehensive tunneling ma- chine cutting easier. Take Taoyuan Coal Mine of Huaibei Mining Group as an example,the theoretical analysis and nu- merical simulation on the blasting crack and damage range of original rock stress were conducted,on the basis of this, the parameters of large diameter deep hole advance blasting was designed and tested. The research results show that the range of Von Mises stress more than 177 MPa was 0. 424 m around blasting hole,the hole diameter was 75 mm,the charge diameter was 63 mm,and a fracture zone was formatted. Its damage range was from 0. 424 m to 2. 3 m. After blasting,comprehensive machine excavation speed increased by 40% to 50% and cutter consumption was reduced by 52. 4% . Blasting vibration measurement and analysis show that blasting vibration energy was focused on the frequency range from 50 Hz to 160 Hz,and there was no damage to the roadway surrounding rock and supporting structure.