大冶铁矿爆破开采巷道围岩累积损伤规律研究

Study on Cumulative Damage Law of Rock Mass under Blasting Loading in Daye Iron Mine

大冶铁矿东采场采用无底柱分段崩落法开采,频繁的中深孔爆破作业产生的爆破振动不可避免地对巷道围岩产生累积损伤,甚至诱发岩体的失稳破坏。结合大冶铁矿地下开采的生产实际,对其爆破开采所产生的爆破振动进行了监测,并对巷道围岩在爆破振动作用下的损伤累积规律进行了分析。试验数据表明,在单响药量和爆心距变化不大的情况下,随着爆破次数的增加,爆破振动的损伤逐步累积,损伤参数呈对数函数趋势增加。因此,尽管每次爆破诱发的爆破振动都低于《爆破安全规程》的控制标准,但爆破振动对围岩的损伤会不断的累积,不断使岩体的性能劣化,因而应视实际情况在爆破开采至一定次数后对巷道围岩进行检查和加固,以确保生产的安全。

The sublevel caving mining method is used in Daye Iron Mine. The blasting vibration induced by the recurrent deep hole blasting will produce cumulative damage to surrounding rock mass of underground space, and e- ven induce rock mass fracture or instability. According to the actual underground mining production of Daye Iron Mine, the blasting vibration was monitored, and the blasting vibration damage accumulation law in the surrounding rock was analyzed. With the similar blasting charge and distance, the blasting vibration damage gradually cumulative when the blasting times increasing. The damage parameter D was a logarithmic function of blasting times. Thus, al- though each blasting vibration was below the control standards of Blasting Safety Regulations, the blasting vibration damage to the surrounding rock mass still accumulated and fractured the rock mass. Therefore, to ensure the safety of production, the surrounding rock mass should be checked or reinforced after a certain blasting times.