关键词: 露天矿, 爆破, 相对损伤因子, 钻孔注水, 现场试验

Abstract: Drilling blasting is the main mining mode in open-pit mine. Impact effect induced by blasting will lead to damage and fracture of rock surrounding the blasting area; and then affect the stability of slope. An approach to evaluate equivalent damage field of rock induced by blasting is introduced; and it is named as borehole water seepage field test. Some steps should be taken in this method. Through water seeping in each testing borehole, recording water level and seepage time, drawing water level and seepage time curve, and at last, analyzing it, the damage degree and damage depth are obtained. A relative damage factor is used to represent the damage degree induced by blasting, and the intersection point between sharp decreased stage and gentle changing stage is used to denote damage depth and damage distance. According to field testing; the maximal damage distance of rock induced by blasting is 20 m approximately; and maximal damage depth is about 12 m. The blasting resistance of iron ore is stronger than limestone. At same position, the relative damage factor of iron ore is 7.5% smaller than limestone; the maximal damage depth and maximal damage distance of iron ore is 4-6 m smaller than limestone. Sometimes, water level will decrease to certain elevation rapidly, and then keeps constant. It means a penetrated fractured zone forms; and the electronic peering instrument would be used to observe and check this phenomenon.

Key words: open-pit mine, blasting, relative damage factor, water seepage in borehole, field test