煤矿岩巷爆破掘进炮孔密度优化研究

岩巷掘进工作面的炮孔密度(全断面炮孔数与断面面积之比)很大程度上影响了凿岩工作量和爆破效果,为了实现岩巷的快速掘进,需要对岩巷爆破的掏槽结构和其他爆破参数进行优化,在保证爆破循环进尺和巷道周边成型质量的基础上减少全断面炮孔数目,降低炮孔密度。根据在岩巷爆破掘进现场收集的资料,建立岩巷掘进爆破参数数据库,其中包含施工时间、矿区位置、掏槽方式、岩石普氏系数、掘进断面面积、全断面炮孔数目、炮孔深度、炸药单耗和炮孔利用率9个特征参数。通过对关键参数下的炮孔数目与断面面积进行线性拟合,得出关键参数在不同区间的炮孔密度变化规律,研究表明:大部分工程的炮孔密度约为5个/m²;炮孔密度与各参数具有一定相关性。其中,中深孔爆破的炮孔密度拟合值大于浅孔爆破;炸药单耗增大时,炮孔密度明显降低;炮孔利用率增大时,炮孔密度出现增大趋势;硬岩巷道的炮孔密度显著大于软岩;斜孔掏槽形式下的炮孔密度大于直孔掏槽的炮孔密度。炮孔密度较大是由于受到岩石破碎机理影响与爆破技术的限制,从而提出改进爆破技术,即采用二阶二段掏槽技术和周边孔切缝药包定向断裂控制技术。通过现场试验,发现同时采用二阶二段掏槽和周边孔切缝药包定向断裂控制技术既能够大幅降低炮孔密度,由5个/m²降到4个/m²,还可以保证爆破效果。研究对提高我国煤矿岩巷的快速掘进水平具有参考价值。

Optimization of blasting hole density in rock roadway driving

In order to realize the rapid excavation of rock roadway,it is necessary to optimize the cutting structure and other blasting pa?rameters of rock roadway blasting.On the basis of ensuring the blasting cycle footage and the surrounding quality of the roadway,it is nec?essary to reduce the number of full section blastholes and reduce the blasthole density.According to the data collected in the rock roadway blasting excavation site,the blasting parameters database of rock roadway excavation is established,which includes nine characteristic di?mensions:construction time,mining area location,cutting mode,rock firmness coefficient,excavation section area,number of holes in the whole section,hole depth,explosive consumption and hole utilization rate.Through the linear fitting of the number of blastholes and cross-section area under the dimension of key parameters,the variation law of blasthole density of key parameters in different intervals is obtained.It is found that the blasthole density of most projects is about 5 per square meter,and there is a certain correlation between the blasthole density and various parameters.Among them,the fitting value of blast hole density of medium deep hole blasting is greater than that of shallow hole blasting;the blast hole density decreases significantly with the increase of explosive consumption;the blast hole density increases with the increase of blast hole utilization;the blast hole density of hard rock roadway is significantly greater than that of soft rock;the blast hole density of inclined hole cutting is greater than that of straight hole cutting.It is concluded that the high density of blast hole is affected by the mechanism of rock fragmentation and the limitation of blasting technology.Therefore,the improved blasting technol?ogy is proposed,that is,the second-order two-stage cutting technology and the directional fracture control technology of peripheral hole slotting cartridge.Through the field test,it is found that the directional fracture control technology of two-stage two-stage cutting and pe?ripheral hole slotting charge can greatly reduce the blast hole density from 5 holes/m2 to 4 holes/m2,and ensure the blasting effect.It is of great significance to improve the rapid excavation level of rock roadway in China.