爆破作用对地下金属矿山围岩稳定性的影响

STUDY ON EFFECTS OF BLASTING ON STABILITY OF SURROUNDING ROCKMASS IN UNDERGROUND METALLIC MINE

为分析爆破作用对地下金属矿山围岩稳定性的影响,截取夏甸金矿具有代表性的VII–2矿体剖面,利用光纤光栅传感器对现场爆破作用下的围岩应变进行监测;同时,利用现场取得的爆破地震波,结合夏甸金矿的实际开采状况,对爆破作用下围岩的稳定性进行数值模拟计算。依据数值模拟计算结果对围岩监测点的布置位置进行优化。研究结果表明,光纤光栅传感器能够有效地监测到爆破作用造成的围岩微应变,利用光纤光栅进行矿山围岩稳定性监测是可行的。爆破作用对自身巷道的影响最大,巷道近区围岩的应力和安全系数变化较大,但对相邻巷道的围岩稳定性影响较小。依据爆破前后巷道的位移、应力、加速度和速度变化规律,在布设传感器监测点时将规律点和关键点相结合,定期监测和长期监测相结合,并适当增设补充点,能够对巷道监测关键点的布置进行有效优化,提高监测的针对性。

In order to study the effect of blasting on the stability of surrounding rockmass in underground metallic mine,fiber grating sensing system is used to monitor the strain of the surrounding rockmass on the effect of the blasting on a typical cross-section VII-2 in Xiadian Gold Mine.Combined with the practical exploration approaching,the stability of surrounding rock is computed using the earthquake wave achieved from the site.According to the result of the numerical simulation,the layout of the sensors is optimized.The presented work shows the fiber grating sensing system is able to monitor the micro-strain of the surrounding rockmass caused by blasting.It is feasible that using the fiber grating sensing system to monitor the stability of surrounding rock in underground metallic mine can be adopted.The effect of blasting to the exploded tunnel is larger than nearby tunnels.The stress and the coefficient of the nearby surrounding rock are changed and attenuated by the distance.When disposing the monitoring point of sensors,the regular point is combined with the key point,and periodical monitor is combined with the long-term monitoring.According to the change regularity of the displacement,stress,acceleration and velocity of tunnels before and after exploded,the layout of the key monitoring point is optimized which will improve the aim of monitor.