为了提高云南省某锡矿小断面巷道掘进炮孔利用率，降低炸药单耗，基于正交试验的原理，对角柱形掏槽爆破参数进行优化。经分析确定，以装药量、装药孔距空孔的距离、空孔孔径和填塞长度作为试验因素，炮孔利用率和槽腔体积作为试验指标，每种因素取3个水平；通过极差和方差分析研究不同因素对试验指标影响的显著性，确定试验因素的最优组合。研究结果表明：对于小断面巷道掘进角柱形掏槽，当空孔孔径为70 mm，装药孔距空孔的距离为10 cm，装药量为3 kg，炮泥填塞长度为20 cm时，掏槽能够取得良好爆破效果，经过多次现场巷道掘进试验验证，炮孔利用率可由80%提高至93%以上。

In order to improve the utilization rate of blastholes in small section tunnels in a tin mine in Yunnan Province and reduce the unit consumption of explosives，after analysis，it is determined that the four factors of the charge amount，the distance between the charge hole and the empty hole，the hole diameter and the filling length are the test factors.The blast hole utilization rate and the cavity volume are the test indicators，and each factor takes 3 levels.Using the method of repeated orthogonal experiments，the effects of four different factors，namely，the charge amount，the distance between the charge hole and the empty hole，the hole diameter and the packing length，on the blasting hole utilization rate and the cavity volume were studied through the range analysis and variance analysis.The significance of the influence of each test index determine the optimal com-bination of test factors.The research results show that in the range analysis，the distance between the charge hole and the empty hole has the greatest influence on the utilization rate of the undercut blasting hole，followed by the hole diameter，the charge amount is smaller，and the filling length has the least influence. The hole diameter has the largest impact on the groove volume，the distance between the charging hole and the empty hole is second，the packing length is smaller，and the charging amount has the smallest influence.In the variance analysis，the distance between the charge hole and the empty hole has a very significant effect on the blast hole utilization rate，the hole diameter has a significant effect on the blast hole utilization rate，and the charge amount and packing length have no significant effect on the blast hole utilization rate.The hole diameter has a very significant influence on the volume of the cavity，the distance between the charging hole and the empty hole has a significant effect on the volume of the cavity，and the significant effect of the packing length on the volume of the cavity is slightly weaker than the distance between the charging hole and the empty hole.The amount has the least significant effect on the cavity volume.Therefore，for small section roadway excavation，when the hole diameter is 70 mm，the distance between the charge hole and the empty hole is 10 cm，the charge amount is 3 kg，and the mud filling length is 20 cm，the undercut can achieve excellent blasting effect.After several on-site roadway excavation tests，the blasthole utilization rate can be increased from 80% to more than 93%.