矿柱爆破回采对胶结充填体损伤影响试验研究

Experimental Study on the Effect of Pillar Blasting Mining on the Damage of Cemented Filling Body

为确定井下矿柱爆破回采对胶结充填体的破坏范围,选用大红山铜矿现场胶结充填体及同等强度的矿柱模拟材料,在井下废弃但安全的巷道内开展矿柱爆破回采模型试验,并采用超声波测试及爆后表观裂纹观测的方法,分别从损伤度变化和裂纹扩展2个方面探究爆破荷载下胶结充填体的损伤规律。研究结果表明:爆破荷载下胶结充填体在爆心距为45~125 cm的损伤度明显高于爆心距为145~205 cm的损伤度;胶结充填体处裂纹最长可扩展至71.5 cm;根据试验模型中胶结充填体损伤情况,将其划分为稳定区、损伤区和破坏区,该配比下胶结充填体损伤度0≤D<0.07为稳定区,0.07≤D≤0.22为损伤区,0.22<D≤1为破坏区。

Based on the panel mining of Dahongshan Copper Mine,this paper attempts to solve the damage problem of adjacent cemented pillars.In order to determine the damage range of cement piles in the blasting and recovery of underground mines,the on-site cemented backfill of Dahongshan Copper Mine and the same strength of the pillar simulation materials were used to carry out the mine column blasting simulation test in the underground abandoned but safe roadway.Ultrasonic testing and post-explosion apparent crack observation method were used to investigate the damage law of cemented backfill under blasting load from two aspects of damage degree and crack propagation.The results show that the damage degree of the cemented backfill at the blasting distance R is 45~125 cm that is higher than that of the blasting core R is 145~205 cm;The crack at the cemented backing can be extended to 71.5 cm;In the model,the damage of cemented backfill is divided into stable zone,damage zone and failure zone.The damage degree of cemented backfill is 0≤D<0.07 in the stable zone,0.07≤D≤0.22 in the damaged zone,and 0.22<D≤1 in the failure zone.