Abstract: The appropriate evaluation of the shallow buried tunnels in weak surrounding rock mass under unsymmetrical loading conditions is significant important for the tunnel design and construction. This paper presents a case history of construction of Hongshigou Tunnel. The stress field, plastic zones as well as deformation field of the unsymmetrically loaded shallow tunnel is simulated under different soil cover height by numerical analysis. The failure mode of the surrounding mass is also studied.

Key words: Tunnel Engineering, Shallow Buried and Unsymmetrically Loaded, Instability, Numerical Simulations