Study on the Deformation and Safety in the Process of Shallow Buried Tunnel Construction

The surrounding soil mass were disturbed by the construction of urban shallow buried tunnel, and the ground traffic and architectures were also influenced. Thus, research on the stratum deformation regularity of tunnel has a great positive significance. Take a tunnel in Wuhan as an example; the disturbances were different through adopting different construction sequences to soil. The deformation regularity would be gained from simulation analysis by software ANSYS. The results showed that the maximum value of the vertical displacement reached 3.73cm on surface and the maximum value of the horizontal displacement approached 0.88cm near the transversal medial axis of tunnel. It indicated that the upper soil mass was evidently influenced by construction sequences. The bilateral soil mass was pulled towards the direction of tunnel in tension. With the increase of the width of the shallow tunnel, the displacement of ground increased sharply and the negative maximum displacement value appeared in the transversal medial axis of tunnel neighborhood. Following analysis results, a reasonable construction sequences and the excavation methods are necessary for the tunnel construction. Tilting and subsidence value were used to the safety evaluation of tunnel. Advanced support and secondary lining could be adopted for a higher safe requirement.