| With the increasing of urban scale and urban population sharply raised,the floor space of the city has not been meet the needs of economic development,so the development and utilization of underground space has become the inevitable trend of urban development,and on the choice of construction method,shield construction method have been used by more and more.Many cities have begun preparations for the underground railway construction,due to the increasing of subway lines,will inevitably be in construction process of shield on the existing structure and a large impact on pile foundation.How to reduce surface subsidence and its influence on adjacent pile foundation in shield construction is an urgent problem to be solved in the project.Therefore,it is very important to study the impact of subway shield construction on the ground and bridge pile foundation.In this paper,combined with shenyang metro line 10 BeiDaYing street station in the east side wear a ring a shield interval viaduct as engineering background,using the finite element numerical simulation software MIDAS GTS NX,the excavation of shield tunnel construction under the condition of different effects on the viaduct pile foundation.On-site real-time monitoring and numerical simulation,the method of combining the further studies of the changes of different parameters in the process of excavation of shield effect on the surface and the deformation of pile foundation,mainly for the following research work:(1)Combined with the technical characteristics of the shield construction and its deformation mechanism,the impact mechanism of tunnel excavation on the surface and near the bridge pile deformation is analyzed.(2)According to the specific conditions of the surrounding environment of the tunnel and the construction method of the tunnel,on-site data collection of surface settlement,bridge settlement and displacement around the construction site will be carried out.Monitoring data will be analyzed and summarized,and surface settlement and bridge deformation curves will be drawn to obtain the shield opening.Digging the general rules of surface deformation and bridge deformation.(3)Combined with practical engineering,the finite element analysis software MIDAS GTS NX geotechnical engineering side wear of shield tunnel adjacent pile foundation of 3D finite element model,analyzes the stages of shield construction surface subsidence and deformation of the bridge pile foundation.At the same time,the paper analyzes the different soil property,buried depth,tunnel diameter and the influence of tunnel lining material on the surface subsidence,horizontal distance of different tunnels and Bridges,the soil parameters and excavation process influence on adjacent viaduct pile foundation,provide reference and basis for optimization of construction scheme.(4)Combined with the measured data in the project and the simulation data obtained in different construction parameters,the obtained results are analyzed and verified,and the optimization is carried out on the basis of the original design scheme.MIDAS GTS NX software was used to establish the optimized construction model and the internal force and deformation of the ground and pile foundation were compared and analyzed.Through the analysis of the two kinds of construction schemes,the surface of the optimized scheme and the deformation of the pile foundation increase slightly,but the construction speed is increased and the construction cost is reduced,providing a good foundation for the shield construction to be carried out quickly and orderly. |
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