Research On The Changing Rule Of Ground Deformation Caused By Construction Of Subway Tunnel With Shallow Tunnelling Method In Loess Area

Metro transportation is a green vehicle for cities, which could both help to implementrational urban construction layout and to alleviate road traffic pressure in cities. However, alot of tunnel engineering problems emerged and required urgent solutions during massivemetro development. Therefore, how to predict and effectively control surface deformation aswell as protect existing buildings and under-ground pipes infrastructure during metrodevelopment has become an important theme for us to answer and investigate.This paper takes metro line1(from SaJin-Bridge to North street) in Xi’An city as theengineering background and field measurement and monitoring as fundamental, adopts theinvestigation method combined of theoretical analysis and finite element numerical analogueto conduct research on the surface deformation rule of yellow soil in Xi’An arose by themetro tunnel construction.Through the analysis of the surface deformation when we use shallow tunneling methodduring subway construction,we have summarized the change of the in situ stress, theconsolidation settlement of soil and formation of the loss. And analyze the factors whichinfluence ground surface settlement the most in the subway construction at the same time.Software MIDAS is adopted to build the numerical models to analyze the effect of differentfactors on Soil deformation characteristics and tunnel traits when we conduct excavations.Especially focus on the deformation response of rock and soil mass, stress distribution andsurface deformation. This paper analyzed the deformation tendency of surrounding rocks andthe dynamic information of surrounding rocks and its strut and give feedbacks based on field measurement and monitoring. Numerical simulation is conducted for Metro line1of Xi’Ancity based on construction parameters, Engineering geological and environment conditions.The result of simulation and field measurement has been compared to reach dynamic changeof displacement and the stress of surrounding rocks. The analysis in land surface deformationhas laid scientific groundworks for design optimization and implementation orderoptimization in metro tunnel construction.