摘要
为提高隧道爆破质量,降低爆破施工过程中对围岩的扰动,有必要对原有爆破方案开展优化研究。以某在建铁路隧道平行导洞为工程背景,在总结分析原爆破方案存在超欠挖严重、作业环境差及施工进度慢等问题的基础上,结合围岩特性,通过采用经验公式对炸药单耗、炮孔数量以及各炮孔参数等进行理论计算,确定出更为合理的爆破参数;将原爆破方案中大直径中空孔的数量由8个改为2个,并调整掏槽孔的布置形式,使得掏槽孔爆后为后续炮孔提供更好的自由面,提高爆破效率;同时装药结构的孔口部位使用水袋堵塞,降低了爆后隧道内粉尘和有害气体的浓度,综合以上三方面提出了合理可行的优化爆破方案并进行现场应用。结果表明:采用优化后的爆破方案,可将平均线性超挖量由原来的0.2~0.4 m降低到0.15 m之内,掌子面与底面平整光滑,围岩的超欠挖现象得到了有效控制。同时每循环较原方案可减少炮孔数量37个与炸药使用量49.2 kg,节省施工作业时间1.1 h以及成本约0.08万元,具有较为显著的技术效果和经济价值,从而也验证了优化后爆破方案的可行性。
In order to improve the quality of tunnel blasting and reduce the disturbance to surrounding rock during blasting construction,it is necessary to carry out optimization research on the original blasting scheme.Taking the parallel guide tunnel of a railway project as the engineering background,more reasonable blasting parameters are determined by using the empirical formula to calculate the powder factor,the number of holes and the parameters of each hole,aiming at the problems such as serious over-under excavation,poor working environment and slow construction progress.The number of medium and large diameter empty holes in the original blasting scheme is changed from 8 to 2,and the layout of cut holes is adjusted to provide better free surface for subsequent holes.At the same time,the orifice of the charging structure is blocked by water bags,which reduces the concentration of dust and harmful gases in the tunnel after explosion.The results show that the average linear over excavation can be reduced from 0.2~0.4 m to 0.15 m with smooth working face and bottom by using the optimized blasting scheme.At the same time,compared with the original scheme,the number of holes and the amount of explosives used in each cycle can be reduced by 37 and 49.2 kg,respectively.In addition,the construction time can be saved by 1.1 h and the cost is about 800 yuan,which has a relatively significant technical effect and economic value,and also verifies the feasibility of the optimized blasting scheme.
作者
宋森森
霍润科
SONG Sen-sen;HUO Run-ke(School of Civil Engineering,Xi′an University of Architecture and Technology,Xi′an 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi′an 710055,China)
出处
《爆破》
CSCD
北大核心
2023年第4期66-72,81,共8页
Blasting
基金
国家自然科学基金项目(41172237)
冻土工程国家重点实验室开放基金项目(SKLFE202107)。
关键词
铁路隧道
空孔直线掏槽
参数设计
超欠挖
方案优化
railway tunnel
burn cut blasting with empty hole
parameter design
overbreak and underbreak
scheme optimization
