Investigation On Settlement By Tunnel Underground Excavation Underpassing Existing Railway

In currently,China being in urbanization speed propulsion stage. This gives China an existing urban transport infrastructure, a huge challenge, with further accelerate the process of urbanization, expansion of urban underground space becomes more and more important, subway construction has become China’s first choice. In the urban underground space development, urban subway and other major projects there are a lot of problems to be solved, including the subway tunnel under the surface wear caused by deformation of the existing line, becoming the hotspot of underground construction, the construction and safety line buildings and structures on the social importance of the safety and economic value.Taking Shijiazhuang subway tunnel under the sheets Zhang-Xi wear Existing railway line between actual engineering background, construction zone table Mainland settlement risk monitoring study and numerical simulation of surface subsidence control sensitivity factors were analyzed. The main contents and results are as follows:(1) Summarizes the shallow buried tunnel excavation mechanism of surface subsidence caused by the impact of surface subsidence factor and in-line tunnel caused surface subsidence deformation law expounded risk monitoring index system through the existing line of the subway tunnel.(2) According to the existing railway line through the monitoring of data in the two-lane tunnel excavation, analysis of existing railway gauge the level of risk impact of tunnel construction is within the scope of monitoring operations; study the interaction between the tunnel under construction close the Intensive and surface ground rule for settlement of embankment settlement; calculate the wear section of the railway formation loss coefficient and settling tank under double tunnel.(3) Systematic analysis of tunnel excavation led to subgrade settlement over control values of reason, in-depth study of the control measures in effect, by monitoring the railway ground roadbed deformation data, indicate in isolated pile reinforcement, protection bridge piles, abutments settling effect is remarkable.(4) The tunnel excavation was simulated, and the impact of surface subsidence nine factors were simulated sensitivity analysis, each factor and multi-factor coupled to ground subsidence induced control action.(5) By three-dimensional laser scanning and numerical simulation of wear at Shijiazhuang railway subway tunnel lining segment deformation were compared to verify the reliability of the numerical simulation model.