3D numerical analysis of influence of construction of underlying mining area on existing road tunnel structures

Based on the FEM method, a 3D numerical model for mining areas under the existing road tunnels is established. The analysis is made on the deformation and mechanical characteristics of structures during the construction of tunnels and mining areas so as to investigate the influence of construction of underlying mining areas on the existing tunnel structures. The results show that the influence of the underlying mining areas on the road tunnels is significant. The effect range of the mining area on the road tunnels is about 25 m from its centerline alone the tunnel axis, while the main effect distance of construction of the mining area on the tunnel structures is about 30 m before and after the centerline from the working face to the tunnel. The adverse effect must be taken into consideration during the design and construction of road tunnels in the mining area, and some monitoring and pre-strengthening methods should be adopted.