煤矿岩巷掘进爆破掏槽孔超深问题探讨

Discussion on ultra-deep depth problem of slot hole in blasting excavation of rock roadway in coal mine

掏槽技术是影响煤矿岩巷钻爆法掘进效率的关键,为了探讨掏槽孔超深深度(掏槽孔与非掏槽孔深度之差)与炮孔利用率之间的关系,采用文献检索法和现场试验开展相关研究,以近40年岩巷爆破掘进实际案例为对象,从时间、岩性、断面大小、炮孔深度、掏槽形式等5个维度对我国煤矿岩巷掘进施工相关文献进行了统计分析研究。研究结果表明:自20世纪80年代以来,岩巷爆破设计的掏槽孔超深深度均设定约为200 mm,炮孔利用率维持在90%左右,5个维度中岩性对炮孔利用率的影响最为显著,并就掏槽孔超深深度为200、300、400和500 mm时进行了现场爆破试验,炮孔利用率较超深深度为200 mm时的89%分别提高到93%、97%和97%,最大提高了8%,试验条件下掏槽孔超深深度的最优为400 mm;掏槽孔超深深度与炮孔利用率具有较强的相关关系,适当加大掏槽孔超深深度能显著提高炮孔利用率,而不同施工条件下掏槽孔超深深度的确定有待研究。

The cutting technology is the key of affecting the efficiency of drilling and blasting method of rock roadway in coal mine.In order to explore the relationship between the ultra-deep depth of the cutting holes( the difference between the depth of the cutting hole and the non-cutting hole) and the utilization rate of the blast hole,a literature search was used combined with field tests. Taking the actual cases of rock tunnel blasting in the past 40 years as research objects,the relevant literature on the construction of coal mine rock tunnels in China were analyzed from five aspects including time,lithology,section size,blast hole depth,and trenching form. The research results show that since the 1 980s,the ultra-deep depth of the slotted holes designed for rock blasting has been set to about 200 mm,and the blasthole utilization rate has been maintained at about 90%. Among the five aspects,lithology has the most significant effect on the blasthole utilization rate.On-site blasting tests were carried out on the ultra-deep depths of 200,300,400,and 500 mm. The utilization rate of the holes was increased to 93%,97%,and 97% from 89% when the ultra-deep depth was 200 mm. The maximum increase is 8%. Under test conditions,the optimal depth of the slotted hole is 400 mm;there is a strong correlation between the ultra-deep depth of the slotted hole and the utilization rate of the blast hole. Increasing the ultra-deep depth of the slotted hole can significantly increase the utilization rate of the blasted hole,and the determination of the ultra-deep depth of the slotted hole under different construction conditions needs further study.