Study On The Influence Of Rectangular Pipe Jacking Tunnel Construction On Stratum And Adjacent Underground Pipeline

In recent years,with the development of urban construction in China,the development and utilization of urban underground space has become faster and faster,and it has become a trend to prohibit large-scale surface excavations in urban central areas.Non-excavation methods such as the pipe jacking method have the advantages of less excavation and small excavation on the surface,and will be increasingly used in the construction of urban municipal engineering in the future.This paper relies on a 220 k V line project in the southern Hebei power grid to study the deformation of the stratum and adjacent underground pipelines caused by the construction of a rectangular pipe jacking tunnel.The main research contents of the paper include:(1)By reading a lot of literature related to the pipe jacking project,theoretical analysis and research on the mechanism of bentonite mud in the construction of rectangular pipe jacking,the effect of grouting on soil deformation,and the effect of grouting.The theoretical calculation formulas of head-on resistance,friction resistance,and thrust in rectangular pipe jacking are summarized.Analyze the disturbance mechanism of pipe jacking on the surrounding soil.(2)With the help of FLAC3 D software,the surface soil displacement,underground layered soil displacement and soil stress caused by the rectangular pipe jacking method were studied.The law of displacement and stress of palm surface under different support pressure is given,and the law of surface soil deformation and plastic zone change under different support pressure and grouting pressure is given.(3)The displacement and stress of the underground pipeline caused by the construction of the rectangular pipe jacking are studied,and the displacement and stress of the pipeline under different support pressure and grouting pressure are given,the effect of existing pipelines on deformation is given(4)Aiming at the characteristics of the construction of rectangular pipe-jacking tunnels,the measures for reducing soil deformation and the protection measures for underground pipelines are summarized.The numerical simulation is used to analyzethe protection effect of the isolation method and soil reinforcement method on the pipeline.