龙南隧道一号斜井合理光面爆破参数的确定

Determination of Reasonable Smooth Blasting Parameters for No.1 Inclined Shaft in Longnan Tunnel

为确定龙南隧道一号斜井合理的光面爆破参数,在给定光面爆破参数选取原则的基础上,结合斜井实际工程地质条件确定两组光面爆破方案.对比两组爆破方案开挖效果可以得出:(1)当炮眼密集系数K=l时,平均超挖量为12.9 cm,半眼孔痕率为80%;炮眼密集系数K=0.83时,平均超挖量为11.5 cm,半眼孔痕率为85%.因此,斜井采用0.83的炮眼密集系数能取得较好的光面爆破效果.(2)当掏槽眼间距较大时,适当增加抛渣眼能够使岩石充分抛掷出,减少大块岩石的产生,有利于提高开挖循环进尺.(3)由现场实际爆破效果对比发现龙南隧道一号斜井采用第二组爆破方案取得的爆破效果较好,可为类似工程提供参考.

In order to determine the reasonable smooth blasting parameters for No.1 inclined shaft in Longnan Tunnel, based on the principle of selecting the smooth blasting parameters, two groups of blasting schemes are determined. Comparing the excavation results of the two blasting schemes, we can get the following results: (1) When the blasthole density coefficient K =1, the average overdigging capacity is 12.9 cm, and the half hole mark rate is 80%. When the blasthole density coefficient K=0.83,the average overdigging capacity is 11.5 cm, and the half hole mark rate is 85%. Therefore, the blasthole density coefficient of 0.83 can be used to achieve better smooth blasting effect. (2) When the gap between the slotted holes is large, the rock could throw out enough to reduce the mass by increasing the dross hole, improving the driving circular footage. (3)Based on the comparison of actual blasting effect on site, it is found that the blasting effect obtained by the second group blasting scheme in the inclined shaft of Longnan Tunnel is good, which could provide reference for similar projects.