邻近营业线隧道小净距控制爆破施工技术

重庆枢纽北左、北右联络线隧道与既有蔡东联络线双碑隧道水平最小净距只有7 m,设计采用控制爆破施工,要求既有隧道爆破振速不大于5 cm/s,施工难度极大。为减少施工对既有隧道的影响,通过试爆获得振动衰减规律,验证开挖方式的可行性,利用试爆结果,完善了最终的爆破方案,并在正式施工中得到了成功应用,保证了重庆枢纽联络线隧道开挖工程的安全高效完成。

Construction Technology of Small Spacing Tunnel Blasting Control Adjacent to Business Line

The level minimum net distance between the north left and north right connecting line tunnel of Chongqing hub and existing Shuangbei tunnel on Caidong connecting line is only 7 m. It is designed to use controlled blasting construction which requires the existing tunnel blasting vibration velocity should be less than 5cm/s, which makes it a difficult construction. In order to reduce the construction influence on existing tunnel, the attenuation law of vibration test to obtain, verify the feasibility of excavation; with the test results, the blasting scheme successfully was finalized and applied in the formal construction, which ensures the safety and efficient completion of excavation engineering of Chongqing terminal connecting line tunnel.