Explosive charge design for tunnel-driving blasting in broken rocks

In order to get a high blasting efficiency for driving a tunnel through broken rock,and make the damage in remaining rock from blasting minimum and protect the original remaining rock stability,the research on the explosive charge for tunnel-driving blasting in broken rocks is finished.The explosive selecting,charge quantity and structure deciding,and corresponding blasting parameters for perimeter shot-holes are analyzed.From the analyses,it benefits for the realization of good blasting results to select the low-explosion-velocity explosive and calculate the corresponding blasting parameters,charge the shot holes by air-explosive structure,fire every other perimeter shot hole in sequence and design correspondingly the blasting parameters for perimeter holes.The method is worthy for quickening the tunnel-driving and making the remaining rock damage from blasting minimum and the remaining tunnel rock protected effectively.