Abstract: With the rapid development of the urban rail transit construction, the number of new subway tunnels crossing through existing old railway tunnels at short distance is increasing. Based on the complex geological environment of the existing old Beijing Guangzhou railway tunnel and the current condition of the structural damage and the serious water leakage, the alignment selection options of crossing the old tunnel by the east station of the Railway College and Yuhuating station of the Changsha Metro Line 7 is analyzed, the design options of the shielded, underground excavation and open excavation on the west line by means of numerical simulation are compared. After comprehensively considering the conflict with other projects and the slope of the line, the upper crossing options of the west line is selected. Based on the consideration that the disturbance to the existing old tunnel in the lower part is minimal and is conducive to the long-term protection of the existing old tunnel, the open excavation construction is selected and finally the open excavation is selected. This experience provides a reference for the design and construction of similar projects.

Key words: Subway Tunnel, Crossing, Existing Old Tunnel, Design