City Tunnel Shallow Ground Settlement And Control Research

In urban tunnel project, the tunnel construction will inevitably cause the ground subsidence and stratum displacement, the ground subsidence caused by the tunnel construction is often strictly restricted because of the surrounding buildings and numerous underground pipelines, therefore, the study and forecast of the ground subsidence rules seems to be very important. The urban tunnel is shallow, and always constructed with shield method, which has been researched a lot at home and abroad, but the use of shallow tunnel construction method was relatively less, therefore, it is significant to research the rules of the ground and stratum subsidence caused by shallow tunnel construction method. Relying on the monitoring project of the ground subsidence of shallow tunel construction district of Liuyang River Tunnel Exit in Wuhan-Guangzhou Passenger Special Line, this paper studied the rules of the ground subsidence caused by construction of urban tunnels which use shallow tunnel construction method. Main researching work is as follows:(1) The ground subsidence theories on tunnel excavation were summarized, including the stratum subsidence mechanism, the transverse and longitudinal deformation rules of ground subsidence caused by tunnel excavation, as well as several existing ground subsidence predicting method.(2) The ground subsidence of shallow tunnel construction district of Liuyang River Tunnel Exit in Wuhan-Guangzhou Passenger Special Line was monitored. And combined with the monitoring datas, the rules of ground subsidence caused by shallow tunnel construcion were studied and analyzed, concluding the transverse and longitudinal deformation rules of ground and stratum caused by shallow tunnel construction method.(3) Through two-dimensional numerical simulation of the construction and support of the Liuyang River Tunnel, which adopted the three benching tunnelling method and was enclosed with temporary invert archs, the rules of ground and stratum transverse subsidence caused by tunnel excavation were studied, concluding the ground and stratum subsidence rules of runnel excavated with three benching method.(4)Several common forms of ground damage caused by tunnel excavation were analyzed, then ground subsidence control standards and allowed value were analyzed as well. Finally, the ground subsidence control measures and their effectiveness were set forth separately from stratum pre-inforcement, different excavation methods and various types of supporting methods.