炮孔堵塞长度的计算与实验研究

Calculation and Experimental Study of Blast-hole Stemming Length

炮孔堵塞是爆破施工中的一个必要环节,它对爆破质量有着直接的影响。首先分析了炮孔堵塞作用机理及堵塞物的整体运动,分析了在不同装药结构条件下的爆生气体压力的变化规律。然后从牛顿第二定律入手推导出了堵塞物长度与堵塞物在炮孔中整体运动时间的关系式,令岩体破碎成块所用时间等于堵塞物在炮孔中整体运动时间,建立了计算堵塞物最优长度的计算模型,该模型考虑了众多影响因素,符合实际情况。最后在南宁市阳光新城岩体地基爆破开挖现场进行了不同堵塞长度的爆破效果实验,实验结果表明:在堵塞长度为0.4米时,爆破效果是最好的,而在实验的爆破条件下通过理论模型计算出最优堵塞长度是0.35米,理论值与实验值比较接近,证明了理论模型具有一定的正确性,所建立的模型可为爆破施工提供理论指导。

Blast-hole stemming is the necessary links in blasting,it has a direct impact on the quality of blasting.The action mechanism and movement process of blast-hole stemming were analyzed,and the gas pressure variation under different dynamite installation structures were analyzed.From Newton＇s second law,the relationship of stemming length and movement time of stemming in the hole was derived.Let the time in which the rock broken into pieces equal to the movement time of stemming in the hole,the calculation model for calculating hole stemming optimal length was established,many factors were considered in this model and it is consistent with actual situation.The blasting effect experiment of different stemming length were done in the rock foundation of Nanning Sunshine Newcity.The experimental results show that the effect of blasting is the best while the stemming length is 0.4m,but the stemming optimal length is calculated by theoretical model in experimental blasting conditions is 0.35m.The theoretical value is closer to experimental value,so the theoretical model has a definite correctness and can provide theoretical guidance for blasting engineering.