地铁隧道下穿高速公路沉降原因分析与控制要点

Cause Analysis and Control Points of Settlement of Subway Tunnel under Crossing Expressway

随着城市地下轨道交通的发展,地铁隧道下穿既有建构筑物越来越频繁,对周边建构筑物的保护要求亦越来越高。依托青岛市地铁8号线某大断面CRD法暗挖区间,对暗挖区间在下穿高速公路时,因隧道断面尺寸较大,围岩软弱破碎,导致掌子面进入高速公路路基后,引起地表沉降速率突变、累计沉降值预警进行研究;通过分析大断面暗挖施工过程对周边环境及地层的影响,采用洞内注浆措施抬升地层控制沉降,并提出了解决该类问题丝针对性控制措施,可有效控制并补偿因大断面暗挖区间施工造成的地层及地表重要构筑物的沉降。

With the development of urban underground rail transit,subway tunnel underpass existing buildings and structures more and more frequently,and the protection requirements of surrounding buildings and structures are also higher and higher.Based on a large cross-section CRD method of underground excavation section of Qingdao Metro Line 8,this paper studies the sudden change of surface settlement rate and the early warning of accumulated settlement value after the tunnel fece enters the expressway subgrade due to the large cross-section size of the tunnel and the weak and broken surrounding rock when the tunnel undercrossing the expressway.Through the analysis of the influence of the large-section underground excavation construction process on the surrounding environment and stratum,the paper adopts the following measures the grouting measures in the tunnel lift the stratum to control the settlement,and put forward the corresponding control measures to solve the problems,which can effectively control and compensate the settlement of the stratum and the important structures on the surface caused by the construction of the large cross-section underground excavation section.