双重预裂与定向抛掷爆破相结合在露天煤矿削坡减载工程中的应用

Combination of Double Pre-splitting Blasting and Directional Throwing Blasting in Slope Cutting and Unloading Engineering of Open Pit Coal Mine

通过双重预裂爆破和定向抛掷爆破相结合,将高边坡危岩爆破抛掷至指定位置,起到削坡减载的作用。同时,利用双重预裂爆破稳定预留岩体。相对于传统预裂爆破,双重预裂爆破能更好地减弱抛掷爆破对预裂边坡的损坏,在主炮孔起爆前沿开口线形成一层1.0 m左右的破碎带;相对于传统预裂孔形成的预裂缝,保护预留岩体的作用更加明显;与目前使用预裂爆破或者抛掷爆破常规手段进行削坡减载相比,具有效率高、成型快、边坡稳定性好的优点。在黑山煤矿二期削坡减载工程中的实际运用中,一次削坡工程量达30×104m3,边坡成型面积达1×104m2以上。

Double pre-splitting blasting and directional throw blasting were combined in slope cutting and unloading engineering by removing dangerous rock from high slope site to the assigned area. At the same time,the reserved rock was stabilized using double pre-splitting blasting. Compared with traditional pre-splitting blasting,double pre-split blasting could reduce the damage of slope due to throwing blasting by the formation of a layer of 1. 0 m broken zone around the opening line before the explosion of the main holes. Compared with pre-cracking formed by traditional pre-splitting blasting,the protection of retaining rock is much more obvious. And compared with double pre-splitting blasting or directional throw blasting used in slope cutting and unloading,this method has the advantages of high efficiency,fast forming,and the good stability of the slope. It has been used in the second phase of slope cutting and unloading engineering in Heishan Coal Mine. Results show that the engineering quantity of slope cutting is up to 30 × 10~4m^3,and the slope forming area is more than 1 × 10~4m^2.