杭温高铁梧坞超大断面隧道上穿高速公路隧道爆破施工影响分区

Impact Zoning of Blasting Construction of Wuwu Super Large Cross-section Tunnel on Hangzhou-Wenzhou High Speed Railway Passing Through Expressway Tunnel

依托新建杭温高速铁路梧坞隧道垂直上穿既有义东高速公路西甑山隧道工程,建立超大断面近接交叉隧道爆破施工三维数值模型,研究新建隧道不同爆破开挖距离下既有隧道振速分布规律。结合爆破振速分区标准,划分新建隧道爆破开挖影响区和既有隧道纵向影响范围。根据既有隧道实测振速判定其结构安全状态。结果表明:新建隧道爆破施工过程中对既有隧道左拱肩、拱顶产生强影响,左拱肩最大振速可达5.6 cm/s;新建隧道从洞口开挖至0.8D~2.0D、2.9D~3.9D(D为既有隧道跨度)时,先后对既有隧道左线、右线产生强影响,新建隧道开挖至2.5D时对既有隧道右线纵向-0.3D~0.3D范围产生强影响;既有隧道左右线现场实测振速大多数在2.5 cm/s以内,新建隧道爆破施工对既有隧道影响较小。

Based on the project of Wuwu tunnel on the newly built Hangzhou-Wenzhou high speed railway,which vertically crosses the existing Yiwu-Dongyang expressway Xizengshan tunnel,a three-dimensional numerical model for the blasting construction of a super large cross-section close intersection tunnel was established to study the vibration velocity distribution law of the existing tunnel under different blasting excavation positions in the newly built tunnel.Based on the blasting vibration velocity zoning standard,the construction impact area of new tunnel blasting excavation and the longitudinal impact area of existing tunnels were divided.Based on the actual vibration velocity monitoring results the structural safety status of the existing tunnel was determined.The results indicate that the blasting construction process of the new tunnel has a strong impact on the left arch shoulder and arch crown of the existing tunnel,and the maximum vibration speed of the left arch shoulder can reach 5.6 cm/s.When the new tunnel is excavated from the entrance to 0.8D~2.0D and 2.9D~3.9D(D represents the span of the existing tunnel),it has a strong impact on the left and right lines of the existing tunnel.When the new tunnel is excavated to 2.5D,it has a strong impact on the longitudinal range of-0.3D~0.3D of the existing tunnel.The actual vibration velocity on the left and right lines of existing tunnels is mostly within 2.5 cm/s,and the blasting construction of new tunnels has little impact on the existing tunnels.