复杂地层地铁盾构近距离下穿市政隧道变形控制技术研究

Research on deformation control technology of metro shield tunnel underpass municipal tunnel in close proximity in complex strata

在紧邻既有盾构隧道下方新建地铁隧道,必然会导致既有隧道产生不均匀形变,如何控制变形、确保施工安全是亟待解决的工程技术难题之一。文章依托广州地铁12号线云溪公园站—小金钟站区间盾构近距离下穿既有金源路市政隧道项目,研究在上软下硬复杂地层条件下盾构施工对既有隧道沉降变形的影响及控制技术。通过分析工程概况、地层特性及盾构施工条件,提出针对性的保护方案和施工措施,从而有效减小新建盾构隧道施工对既有隧道的影响。为验证保护方案的可行性,采用有限元软件建立盾构下穿隧道的三维模型,并将有限元模拟结果与现场实际监测数据进行对比,验证模型在该工程中的适应性。此外,总结并提出针对盾构下穿既有隧道工程的保护对策和技术措施,可为类似工程施工提供参考和借鉴。

New metro tunnels built immediately below the existing shield tunnel will inevitably lead to uneven deformation of the existing tunnel,how to control deformation,to ensure construction safety is one of the urgent engineering and technical issues that need to be solved.This article relies on the shield tunneling project of Guangzhou metro line 12 Yunxi Park station to Xiaojinzhong station section underpassing the existing Jinyuan road municipal tunnel to analyze the impact of shield construction on the settlement deformation of the existing tunnel and its control technology under the complex formation conditions of soft above and hard below.Based on detailed analysis of the project situation,formation characteristics and shield construction conditions,specific protection schemes and construction measures are put forward,so as to effectively reduce the impact of shield tunneling construction on the existing tunnel.To verify the feasibility of the protection scheme,finite element software was used to establish a threedimensional model of the tunnel under shield tunneling,and the finite element simulation results were compared with the actual monitoring data on site to verify the adaptability of the model in the project.Protection countermeasures and technical measures for the tunnel under shield tunneling project were also proposed,which could provide reference and inspiration for similar projects.