过煤层采空区和断层的隧道开挖控制爆破技术

大同香炉寺山隧道过煤层采空区和断层时采用了上导硐先行的分步开挖方案和微差控制爆破技术。上半断面掘进始终超前下半断面 3～ 5m ,形成小台阶式爆破开挖方式。在上半断面掘进时 ,以超前的导硐为自由面 ,实施光面爆破 ;下半断面的掘进采用预裂爆破。每循环进尺限制在 1 0m以下。爆破中 ,控制最大一段齐爆药量 ,减轻了爆破震动对煤层采空区和断层的扰动。应用综合技术措施 ,使隧道顺利地穿越了地质条件特别复杂的地段。

CONTROLLED BLASTING TECHNOLOGY FOR EXCAVATION OF THE TUNNEL ACROSS THE MINED-OUT AREAS IN COAL SEAMS AND FAULTS

The stepped excavation scheme with an advanced guide hole and the short-delay controlled blasting technology were used for excavation of the Xianglushishan tunnel,in Datong,across mined-out areas in coal seams and faults.The upper excavated semi-section of the tunnel led,at all times,the lower semi-section by 3～5 meters and a small-bench excavation form came into being.During excavation of the upper semi-section,the smooth blasting with taking the guide hole as a free face was carried out.The presplitting blasting was used for excavation of the lower semi-section.The advance per round was limited to less than one meter.In blasting,maximum charge weight per delayed interval was controlled,weakening the disturbance of blasting vibration on the mined-out areas and faults.Because of comprehensive application of the technological measures,the excavation of the tunnel across the sector with very complicated geological conditions was successfully completed.