导爆管雷管与电子雷管在地铁下穿建筑物爆破中的应用对比

青岛地铁一期工程（3号线）五江区间下穿6座高层建筑物,隧道开挖线距离建筑物地下室最小距离11m,距建筑物筏板基础抗浮锚杆最小距离4m。地铁公司要求地下室最底层爆破振动速度控制在2cm/s以内,这严格限制了爆破单段炸药用量。前期采用1～20段毫秒延期导爆管雷管,隧道仅13.9m2的上台阶需分6次爆破,才能满足爆破振速要求,爆破工序时间长,效率低。后采用电子雷管实现了上台阶整体一次起爆,在增大单段炸药量提高掘进进尺的同时,降低了爆破振动速度,提高了爆破效率,加快了施工速度。总体比较,虽电子雷管炸材消耗高,但总成本下降,在环境复杂、爆破振速要求高且工期紧的爆破工程中,具有显著优势。

A Comparison Between the Application of Priming Detonators and That of Electronic Detonators to the Blasting Construction for Underground Buildings of Tubes

The Wujiang Section of the the First-phase Project（Line 3） of the Qingdao Tube has to go under six tall buildings,the minimum distance between the excavation line of the tunnel and the basements of the buildings being only 11 metres, and the minimum distance between the excavation line of the tunnel and the anti-floating anchor rods of the raft foundation of the build- ings being only 4 metres. According to the requirements of the Tube Company, the blasting vibration rate for the lowest layer of the basements should be kept within 2 cm/s, which greatly limits the amount of explosive to be used for each single-section blasting. In that case, during the early-phase construction,stage 1-20 millisecond delay priming detonators are used for blasting, with six times of blasting conducted for the upper steps of the tunnel only 13.9 square metres in area. Only in this way can the required blasting vibration rate be achieved. In that case, the blasting processes take much more time, with the efficiency lower. Later,with electronic detonators used, the blasting for the whole of the upper steps is performed at one stroke, in which case the single-section charge is increased and therefore the drilling footage is increased, with the blasting vibration rate reduced, the blasting efficiency improved, and the construction accelerated. To sum up, electronic detonators enjoy outstanding advantages and lower the general costs, especially for those blasting-rate-demanding and construction-duration-demanding projects in com- plex environmedt, though they may cost more explosive materials.