深孔直眼掏槽爆破装药孔合理填塞长度研究

Reasonable Stemming Length of Charge Hole in Deep Borehole Parallel Cut

在深孔直眼掏槽爆破中,炮孔填塞长度是决定爆破效果优劣的重要影响因素,过长或过短的填塞都会减弱掏槽爆破效果。为提高深孔直眼掏槽的爆破效果,基于冲击波和爆生气体共同作用破岩理论,通过分析装药孔填塞物冲出炮孔运动过程和岩石破碎所需时间关系,得出直眼掏槽中合理填塞长度上下限值计算公式,以此确定合理的填塞长度范围。进行三组模型试验,分析试验产生爆破漏斗情况、爆堆质量和块度。试验结果表明:模型试验中爆破效果最佳实验组的填塞值为20 mm,其值处于理论计算的合理填塞长度19.86 mm至22.07 mm区间,验证了合理填塞长度范围的计算公式的合理性。针对过长填塞导致爆生气体过早从空孔的冲出的情况,提出在深孔直眼掏槽爆破中对空孔上下两端进行适当的堵塞来减弱这种影响。

In deep borehole parallel cut blasting,the length of the blast hole stemming is an important factor to determining the blasting effect.Too long or too short filling will weaken the cut blasting effect.In order to improve the blasting effect of deep borehole parallel cut blasting,based on the theory of rock fragmentation under the combined action of shock wave and explosion gas,by analyzing the relationship between the movement process of the stemming rushing out of the blast hole and the time required for rock fragmentation,the reasonable stemming in the cut is obtained.The calculation formula for the upper and lower limits of the length can determine the reasonable range of the stemming length.Three groups of model tests are carried out to analyze the blasting funnel,blasting pile quality and fragmentation produced by the test.The test shows that the stemming length of the experimental group with the best blasting effect in the model test is 20 mm,which is in the range of 19.86 mm to 22.07 mm of the reasonable stemming length calculated in theory.The reasonableness of the formula for calculating the reasonable stemming length range is verified.In view of the situation that the blasting gas passes through the empty hole due to the excessively long stemming,it is proposed to properly block the upper and lower ends of the empty hole in deep borehole parallel cut blasting to reduce this effect.