Statistical Analysis And Construction Optimization Of Deformation Data Of Beijing Underground Subway Station

With the development of social economy,the progress of science and technology and the acceleration of Urbanization,the problem of dense population and traffic congestion is becoming more and more common in cities,and the emergence of the subway effectively alleviate these problems.Due to the large number of urban surface buildings and the complexity of underground pipelines,the construction of subway station in city often adopts the undermining method.Therefore,how to effectively control the surface subsidence and ground deformation caused by the construction of the subway station is very important.In this paper,we counted all the underground subway stations in Beijing and investigated the data of some stations on the Beijing metro line Four,line Five,line Six,line Seven,and line Ten.By means of statistical analysis,this paper studies the surface and ground settlement of Beijing underground subway station from the aspects of surface subsidence,ground loss and settlement trough width parameter.At the same time,we study the formation response caused by different buried depth of underground subway station based on the project of Beijing metro line Sixteen Suzhoujie station by using Midas GTS and FLAC 3D software.And we use AHP comprehensive evaluation to get the optimal pilot tunnel excavation scheme of PBA method.The main conclusions are as follows:(1)By November 2016,the total number of underground subway stations in Beijing is 78,the most used construction method in Beijing subway station is the PBA method and most of the underground metro stations in Beijing are located in the strata of 4m?10m depth.The most widely used structure type of Beijing underground subway station is three arch double column double deck structure.(2)Through statistical analysis,it is concluded that the control value of 73.90mm as the surface settlement of the underground subway station is more economical and reasonable.To a certain extent,it can reflect the average level of the existing construction capacity and technical status,and will not have a greater impact on the construction of the subway station and the surrounding environment.(3)The statistical analysis was carried out from three aspects:the construction method,the depth of the station and the structure type of the station based on the field monitoring data of Beijing subway station.We fitted the curve of the surface settlement trough of the subway station,and studied the loss rate and the settlement trough width parameter,and the surface subsidence and strata deformation law of Beijing subway station are obtained.At the same time,the influence of the depth of the station on the selection of station structure and the selection of construction methods are analyzed in detail.(4)By using the method of numerical simulation,the paper studies the surface settlement of the station with different depths based on the project of Beijing metro line Sixteen Suzhoujie station.The variation law of the maximum surface settlement,the distribution of plastic zone and the distance of the point of the settlement trough with the depth of burial is obtained.Based on the simulation results,we use AHP comprehensive evaluation to get the optimal pilot tunnel excavation scheme of PBA method.