大断面隧道下穿既有高速公路单侧掏槽+数码雷管干扰减振施工技术

On the One-Side-Cutting+Digital Detonator Vibration-Interfering-and-Reducing Construction Technique for Large-Sectioned Tunnels Under-Crossing Existing Expressways

新建兴泉铁路七里径隧道出口为双线段,其中50 m需下穿既有泉南高速公路供坊隧道,二衬拱顶外缘距高速公路隧道路面仅26 m,要求爆破振动速度不大于5 cm/s,施工难度大。为满足施工安全与工期要求,采用掌子面单侧掏槽+数码雷管干扰减振的控制爆破技术进行开挖,通过单侧掏槽减少药量、调整起爆时差错相减振的方法,达到减振目的。爆破振动速度满足要求,单位炸药消耗量可控制在0.5 kg/m 3左右,日平均进尺2.2 m,安全快速的通过了下穿段。

The exiting section of the newly-built Qilijing Tunnel of the Xingquan Railway is a double-line section,50 m of which has to under-cross the existing Gongfang Tunnel of the Quannan Expressway.As the outer edge of the second lining vault is only 26 m away from the pavement of the expressway tunnel,the blasting vibration speed is limited to no more than 5 cm/s,so the construction is very difficult to carry out.In order to meet the requirements of the safe construction and construction duration,the controlled blasting technique of one-sided cutting in the face and the digital detonator vibration-interfering-and-reducing is adopted for the excavation of the project.The explosive quantity is reduced by unilateral cutting,and the vibration reduction method of error phase is adjusted to realize the purpose of vibration reduction.Through the above-mentioned methods,the blasting vibration speed can be made to meet the requirements,the unit explosive consumption can be limited to about 0.5 kg/m 3,and the average daily footage can reach 2.2 m,which safely and quickly help the tunnel under-cross the under-crossed section.