近距离下穿既有盾构隧道的隧道钻爆降振技术研究

Drilling and blasting technology for closely crossing existing shield tunnel

以广深港客运专线益田路隧道为工程背景,对爆破作用下既有盾构隧道管片的振动响应进行研究。结合应力波理论计算了盾构隧道管片的爆破振动速度安全允许值,并利用现场数据进行验证;结合既有隧道的现场监测数据,分析了管片的振动速度变化规律,提出了减振措施和优化爆破方案,确保既有盾构隧道的运营安全。结果表明:爆破施工过程中,既有隧道衬砌管片最大振速达到7.19 cm/s,小于计算的9 cm/s安全允许振动速度,管片接缝无损伤,计算的衬砌管片安全允许振动速度可为类似工程提供参考;钻爆法近距离下穿既有盾构隧道时,采用电子雷管起爆技术,并结合适当的减振措施,可以有效降低既有隧道衬砌管片的爆破振动速度,确保结构安全稳定。

Taking Yitian Road Tunnel of Guangzhou-Shenzhen-Hong Kong Passenger Dedicated Line as the engineering background,the vibration response of the existing shield tunnel lining structure under blasting is studied.Based on the stress wave theory,the allowable velocity of the blasting vibration of shield tunnel lining segments is calculated and verified by the field data.Combining with the field monitoring data of existing tunnels,the variation law of vibration velocity of lining segments is analyzed,and vibration reduction measures and optimized blasting scheme are put forward to ensure the operation safety of the existing shield tunnel.The results show that the maximum vibration velocity of the existing tunnel lining segment reaches 7.19 cm/s in the process of blasting construction,which is less than the calculated safety allowable vibration velocity of 9 cm/s.The segment joints are not damaged,and the calculated safety allowable vibration velocity of the lining segment can be regarded as a reference for similar projects.When drilling and blasting method is used to closely underpass the existing shield tunnel,the blasting vibration velocity of existing tunnel lining segments can be effectively reduced by using electronic detonator initiation technology combined with appropriate vibration reduction measures to ensure the safety and stability of the structure.