Research Of Railway Tunnel Constructed By Open And Cover Method Adjacent To Existing Structures In Gravel Strata

At present, almost all large and medium-sized cities across the country are in the construction of the subway, a large part of the subway projects are constructed by the open and cover method for reasons of economy and safety, etc. It will involve passing through the complex underground structures taking the open and cover method in cities, The inevitable subsidence may endanger the surrounding building structures, In order to ensure safety construction, This paper carries out the following studies combining Chengmianle line Airport Road Tunne、Shuanliu Airport Tunnel and Chengguan line Lidui Park branch tunnel:(1) According to the stochastic medium theory, predicted the surrounding surface sedimentation caused by open and cover method with Matlab7.0.(2) Considering3main influence factors:the distance between buildings and tunnels, the length and the stiffness of the structure in the direction of the considering section, put forward the calculation method of settlement of shallow foundation buildings in typical gravel strata based on the prediction of surface subsidence.(3) Identified the deformation control value of tunnels constructed approaching municipal pipelines by open and cover method, bridge pile foundation and buildings by investigation and combining with the project in which large diameter municipal pipe galleries stride across pit foundation.(4) Identified the adjacent partition in the construction of open cut tunnels in typical gravel strata by researching pit foundation projects constructed approaching building structures in Chengdu area, and numerical analysing by particle flow code software PFC3D.(5) When the building structure is entirely located on one side of the pit foundation, put forward the relevant control measure s of building structures in different areas of the adjacent partition, and verify the effectiveness of grouting reinforcement when building structures are in the strong influence area.(6) When building structures stride across pit foundation, for the large diameter municipal pipe galleries, it is appropriate to take the control measure of setting support through the scheme comparison and safety evaluation of construction; for bridges, pile foundation underpinning can ensure their safety in construction of open cut tunnel when necessary.