预裂孔逐孔起爆在露天矿破碎带边坡的应用

摘要

攀枝花铁矿进入中深部开采后,露天采场的边坡高度已达105~555 m.随着边坡高度的增加,高陡边坡的局部沉降、垮塌频发,严重威胁采场内人员和设备的安全.针对露天采场的不稳定边坡主要集中在破碎带部位,破碎带的爆破预裂效果较差并且有爆破产生的振动等问题,根据预裂爆破成缝机理,结合破碎带边坡地质特征和延时爆破理论,对破碎带预裂效果较差的原因进行了分析.认为预裂孔逐孔起爆更有利于破碎带边坡的预裂效果,同时能够"引导" 、减轻爆生气体向预留边坡方向的作用,还能降低爆破振动对预留边坡的破坏作用.通过预裂孔同时起爆和逐孔起爆在破碎带部位的对比实验,取得了预裂孔逐孔起爆在孔痕率和爆破减振率上优于预裂孔同时起爆的实验效果.%After Panzhihua iron mine into the mid-deep mining,the height of the open-pit mine slope had reached 105 ~ 555 m.The local settlement and collapse of high and steep slope occur frequently with the height of the slope increasing,it threaten the safety of personnel and equipment.For the problems of stope unstable slope was mainly concentrated in the fracture zone,the pre-splitting effect was poor and the blasting vibration.Based on the mechanism of pre-splitting blasting forming crack,combining the geological characteristics of the fracture zone and the theory of micro-differential blasting,the reasons of the poor precracking was analyzed in the fracture zone.It was believed that the prefracture of precracking hole was more favorable to the pre-splitting effect in the fracture zone slope.And it could guide and reduce the effect of the explosion gas on reserve slope direction.It could also reduce the destructive effect of blasting vibration on reserved slope.Through the comparison test of the pre-slitting blasting simultaneous initiation and the hole by hole initiation,the experimental results of the hole by hole initiation of pre-slitting blasting in the hole trace rate and the blasting vibration reduction rate were better than simultaneous initiation.