预留光爆层工法在大断面隧道安全快速施工中的应用  

Application of Smooth Blasting with a Reserved Layer in Safe and Rapid Advancement of Large-Section Tunnels

作　　者：马春德[1,2] 刘泽霖 龙珊 郑静 张建秋 谢伟斌 MA Chun⁃de;LIU Ze⁃lin;LONG Shan;ZHENG Jing;ZHANG Jian⁃qiu;XIE Wei⁃bin(School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China;Advanced Research Center,Central South University,Changsha 410083,Hunan,China;CCCC First Highway Fifth Engineering Co Ltd,Beijing 100024,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083 [2]中南大学高等研究中心,湖南长沙410083 [3]中交一公局第五工程有限公司,北京100024

出　　处：《矿冶工程》2019年第6期25-28,34,共5页Mining and Metallurgical Engineering

基　　金：新疆维吾尔自治区重大科技专项(2018A03003-2)

摘　　要：针对长大隧道在围岩条件较差时采用全断面一次爆破掘进时光爆效果差、出现超欠挖严重、隧道成形质量差等问题,以G575线新疆东天山隧道出口段为研究对象,基于现场观测数据,分析了影响隧道光爆效果的因素,提出了预留光爆层施工的方法。试验结果表明,预留光爆层工法要求合格的钻孔质量、合理的装药结构,同时减少二圈眼药量与优化起爆网络;临时支护台车支护爆后空区,保证了人员设备安全作业;与普通光爆法相比,预留光爆层方法循环进尺增加了12.5%,炮孔利用率增加了12.5%,周边孔炮孔痕迹率增加了28%,平均线性超挖量减少了9 cm,最大单响药量产生的垂向震动速度减少了1.2 cm/s,具有良好的经济性、可靠性与可行性。该成果对大断面隧道采用全断面爆破掘进、安全快速施工具有指导意义。When full-face blasting is adopted in the advancement of long tunnel with large cross section, especially with poor surrounding rock conditions, there will exist some problems, including unfavorable smooth blasting effect, serious over-excavation and under-excavation and poor quality in tunnel formation. For solving those problems, the factors affecting smooth blasting for tunnel are analyzed based on the on-site observation data for the exit section of East Tianshan Tunnel of G575 Line in Xinjiang, and a preserved smooth blasting layer in the construction is proposed. The test results show that, the qualified drilling, reasonable charge structure, reduction of two-circle charge and optimization of detonation network are required in the operation of smooth blasting with a preserved layer. And a temporary Jumbo is required for supporting the empty area after blasting for ensuring the safety of operators. Compared to the conventional smooth blasting, the smooth blasting with a preserved layer can result in the circulating footage increased by 12.5%, blasthole utilization rate increased by 12.5%, borehole trace rate increased by 28%, linear overcut reduced by 9 cm on average, vertical vibration velocity that is generated by maximum single shot charge decreased by 1.2 cm/s. It is shown that this blasting method, being superior in terms of economic benefits, reliability and feasibility, can be of significance in supporting safe and rapid advancement of large-section tunnels using full-section blasting.

关 键 词：隧道工程 大断面隧道 预留光爆层 支护 爆破 

分 类 号：U455.41+2[建筑科学—桥梁与隧道工程]