城市小净距大小断面隧道交叉口段暗挖技术研究

Research on Mined-excavation Technology for Intersection Between Large and Small Section Urban Tunnel with Small Clear Distance

为解决复杂地层中城市暗挖隧道立体交叉及复杂断面施工难题,依托杭州紫之隧道,研究分析了立体交叉段隧道开挖施工难点,创新了交叉口隧道小净距、大断面开挖技术,即在匝道处采用小断面纵向爬坡挑顶进入大断面,反向扩挖分叉主隧道,并在超小净距隧道施工中运用控制爆破、超前导管及超前预注浆加固地层相结合的措施代替复杂的连拱隧道技术,有效地将隧道大跨度断面沉降变形控制在2 cm以内,确保了隧道的安全施工,为类似工程提供借鉴。

In order to solve the construction problems of urban mined-excavation tunnel grade separation and complex section in complex stratum,this paper,relying on Zizhi Tunnel in Hangzhou,studies and analyzes the construction difficulties of grade separation section tunnel excavation,and innovates the small clear distance and large section excavation technology of intersection tunnel,that is,the small section longitudinal climbing is used at the ramp to enter the large section,the reverse expansion is used to excavate the bifurcated main tunnel,and in the construction of super small clear distance tunnel,the combination of controlled blasting,advanced conduit and advanced pre-grouting is used to replace the complex multi-arch tunnel technology,which can effectively control the settlement deformation of large-span section within2 cm,ensure the safe construction of the tunnel,and provide references for similar projects.