Numerical Analysis Methods for Predicting the Impact on Existing Tunnels during Closely-spaced Tunnel Intersection Construction

This paper proposes a new numerical analysis method for neighboring construction where a new shield tunnel is excavated close beneath an existing tunnel. These tunnels are mathematically modeled using detail 3D shell elements and the ground between the tunnels is modeled using interaction springs. The strength of the interaction springs is determined using stability calculations of the ground above the new shield tunnel. We conducted a trapdoor test that reproduces this neighboring construction and measured the interaction between the intersecting tunnels. The results confirmed that the proposed analysis method can simulate the test result of ground reaction forces and tunnel deformation.