摘要
小净距隧道采用钻爆法进行施工时,为了降低炸药爆炸对隧道围岩造成的损伤,根据隧道围岩的实际情况并结合以往类似工程的施工经验,通过优化掏槽孔的装药结构和参数,将楔形掏槽孔内分为两段进行间隔装药,间隔堵塞长度约为0.5m,孔口堵塞长度约为1.5m.孔口装药段药量为总药量的40％～ 50％,孔底装药段药量为总装药量的50％～60％.掏槽孔内分段装药实施延迟起爆,时间间隔不小于50 ms.采用以上主要减震措施,提出了适用于层状围岩小净距隧道减震爆破掘进技术方案.重庆南涪高速公路上的鸭江隧道小净距段施工采用了减震技术方案,现场监测和隧道施工的结果表明：减震爆破掘进技术方案较常规楔形掏槽爆破方案对于振动强度的降震幅度约为40％,使振动速度满足相关标准的控制要求;减震爆破技术方案对于层状围岩小净距隧道的掘进施工具有良好的适用性.
When the drilling and blasting method was used in the construction of small-distance tunnel,based on the actual situation of the tunnel surrounding rock and the previous experience in similar projects,the charging structure and parameters of the cut holes were optimized to reduce the damage to tunnel surrounding rock from explosion energy.The wedge cut hole was divided into two sections for interval charging with 0.5 m length stemming.The upper stemming length was about 1.5 m.The upper charging amount was 40％ ～ 50％ and the bottom charging amount 50％ ～ 60％ of the total explosive.The delay detonation was applied in two sections of charging and the interval time was no less than 50 ms.The vibration reduction blasting excavation technical program for small-distance tunnel with stratiform surrounding rock was proposed based the vibration reduction technical.The vibration reduction blasting program was applied in the construction of Ya-jiang small-distance tunnel on Chongqing Nanfu express way,the results of on-site monitoring and tunnel construction showed that the vibration reduction rate was about 40％ compared to the conventional wedge undercutting program,and the vibration velocity sufficed the control requirements of the relevant standards.The vibration reduction technology was applicable for the blasting excavation construction of small-distance tunnel with stratiform surrounding rock.
出处
《爆破》
CSCD
北大核心
2013年第4期60-65,共6页
Blasting
关键词
控制爆破
间隔装药
小净距隧道
爆破振动
controlled blasting
interval charging
small-distance tunnel
blasting vibration
