Study on the settlement of large-span metro station's baseplate caused by the tunnels newly built beneath it

The influence of tunnel excavation on adjacent buildings or structures must be considered when new tunnels pass through existing buildings or structures. In this article, based on the project of the Aotidong-Aotizhongxin section of Shenyang Metro Line 9 passing through the existing Aotizhongxin station of Line 2, the numerical simulation was employed to research the settlement laws of the existing station's baseplate by four methods, namely the full-face excavation method, the benching tunneling method, the side heading method, and the center diaphragm (CD) method. Based on the results of numerical calculations, in order to ensure the safe and normal operation of existing station, it was recommended to use the CD method to construct the new tunnels. At the same time, the advanced deep hole grouting reinforcement technology and jack-up technology should be adopted in the process to reduce settlement of the station's baseplate. The CD method proved applicability in the project by comparing the field-monitoring data with the numerical calculation results. The results can provide reference for the design and construction of similar projects in the future.