Deformation analysis of adjacent subway station by different parameters of composite support structure in deep foundation pit

Abstract

The foundation pits become deeper and larger, which will affect the subway structure near the foundation pits during excavation. In order to reduce the influence of foundation pit excavation on subway structure, composite support structure is used in foundation pit engineering. To study the influence of the different parameters of composite support structure in deep foundation pit on the deformation law of the subway stations near the deep and large foundation pit, based on a deep foundation pit project adjacent to a subway station in Beijing, the influence of foundation pit excavation on the deformation law of adjacent stations is analysed by numerical simulation and on-site monitoring. And the relationship between the maximum deformation value of the station and the support parameters such as embedded depth and diameter of the retaining pile, layers and sectional dimension of the inner support is discussed. The conclusions are as follows: 1) The maximum vertical deformation of the station obtained by numerical calculation is 2.76 mm, which occurs in the middle of the station roof. 2) The numerical simulation results are consistent with the on-site monitoring data. 3) The deformation of the station is affected by the embedded depth of the retaining pile and the layers of inner support, and is less affected by the diameter of the retaining pile and the sectional dimension of the inner support.