Analytical Solution of Underneath Tunnelling-Induced Deformation of Existing Tunnel

Tunnelling underneath the existing tunnels are very common these days. It is obvious that the under-crossing tunnelling will affect and even damage the existing tunnels. An analytical method is proposed in this paper to better understand the effects of the under-crossing tunnelling on the existing tunnel. The existing tunnel is modeled as a Timoshenko beam lying on a Kerr foundation. The validity of the analytical solution is verified by a series of centrifuge tests. The parametric study is then carried out to well understand the effect of under-crossing tunneling on the deformation of existing tunnel. The results indicate that the pattern and the magnitude of the deformation of the existing tunnel dependent on the longitudinal shear stiffness, volume loss and the vertical clearance between newly built and existing tunnels.