Research On The Deformation Laws Of Strata And Pipeline Tunnelling Under Existing Pipeline By PBA Method

In recent years,with the continuous development and utilization of underground space,subway tunnels,stations and various municipal tunnels have become more and more common.Underground underground pipelines are distributed underground in the city,such as power grids,water pipes,gas pipes,etc.Newly built tunnels or stations inevitably run through these pipelines,and these pipelines will inevitably cause disturbances during the construction process.Causes deformation of the pipeline and the formation.With the vigorous construction of subway tunnels and various types of municipal tunnels,more and more stations have been constructed with PBA construction methods.In the PBA engineering project,the new station's underpass or sideways existing pipeline has a great influence on its settlement and displacement.Therefore,it is of great engineering significance to study the influence of the PBA station's under-construction on the existing pipeline.The main research work and achievements of this paper are as follows:(1)Collecting cases to summarize the settlement deformation of existing pipelines and soil surface at the station where the current domestic PBA construction method is performed.The numerical simulation method was used to analyze the constructed Huangzhuang and the station,and the settlement values of the surface and pipelines were observed.The results were compared with the measured data of the surface and pipeline settlement above the Huangzhuang Station of Haidian to verify the reliability of model establishment and parameter selection.(2)The new Beitaipingzhuang Station is similar to the Huangzhuang Station.The PBA method is also used for station construction.There are multiple pipelines above the station.The numerical model of the Beitaipingzhuang Station is established by referring to the modeling method,basic assumptions,and parameter selection of the Huangzhuang Station.Simulate the influence of station excavation on existing pipelines.By setting up different working conditions,the impact of station construction on the pipelines and the surface when different angles of burial depth,different horizontal locations,different pipeline diameters,and different angles between pipelines and station axes are studied.(3)There are many factors that affect the settlement of existing pipelines during the construction of the station.A grey prediction model is used in this paper.The effect of each factor on surface settlement,pipeline settlement,and pipeline internal force is analyzed using the single factor method.Knowledge improves parameters in it to make its prediction accuracy more accurate.(4)Based on the above calculations,the effect of station excavation on strata and existing pipelines under various operating conditions was deduced,which provided a reference for the construction of Beitaipingzhuang Station and proposed improvement measures for its construction.