隧道掘进中水封爆破装药结构及其优化研究

Study on Charging Structure of Water Infusion Blasting in Tunnelling and Its Optimization

以延(庆)崇(礼)高速公路(北京段)温泉隧道为工程背景,从爆破振动和粉尘浓度两个角度对水封爆破装药结构进行探讨,选取最优装药结构用于指导工程施工.研究结果表明:(1)两端水间隔装药结构爆破最大振速为3.82 cm/s,大于其它装药结构,而爆破振动信号作为爆炸应力波在围岩中传播的直观表现,振速的大小表示炸药能量有效利用情况,因此两端水间隔装药结构能量利用率最高;(2)两端水间隔装药结构爆破后粉尘浓度为127.25 mg/m3,与孔口水间隔装药结构的126.41 mg/m3相差不大,却小于孔底水间隔装药结构的152.41 mg/m3,考虑到两端水间隔装药结构炸药能量利用率高于孔口水间隔装药.因此,综合分析认为采用两端水间隔装药结构最为合理,由于其能量利用率最高,在相同爆破条件下可以适当降低装药量,降低成本.

In this paper,based on the hot spring tunnel in Yan(Qing)Chong(Li)Expressway(Beijing section)as the engineering background,the charging structure of water infusion blasting was discussed from two angles of blasting vibration and dust concentration,and the optimal charging structure was selected to guide the construction.The results show that:(1)the maximum blasting vibration velocity of water-spaced charging structure at both ends is 3.82 cm/s,which is larger than that of other charging struetures.The blasting vibration signal is used as an intuitive representation of the propagation of explosive stress wave in surrounding rock,and the magnitude of vibration velocity indicates the effective utilization of explosive energy.Therefore,the energy utilization ratio of water-spaced charging structure at both ends is the higbest.(2)The dust concentration after blasting is 127.25 mg/m3 in terms of water-spaced charging structure at both ends,which is similar to 126.41 mg/m'of the charging structure at the entrance,but smaller than 152.41 mg/m'of the charging structure at the bottom,considering that the energy efficiency of water-spaced charging structure at both ends is higher than that of the charging structure at the entrance.Therefore,the comprehensive analysis showed that the charging structure with two ends of water spacing was the most reasonable.Because of its highest energy utilization ratio,the charge quantity could be reduced properly,the cost could be reduced under the same blasting conditions.