Abstract: When large crosssection tunnels run through ground with uneven terrain, different asymmetrical earth pressures are always encountered. Therefore, selecting rational construction methods is very important for the control of the construction mechanical performance of asymmetricalloaded large crosssection tunnels under shallow cover. In the paper, analysis is made on the displacement control and support stress of asymmetricalloaded large crosssection tunnels under shallow cover, by means of numerical simulating on double side drift method, optimized bench method and CRD method. The results show that: 1) When the ground surface inclination angle ranges from 0° to 10°, optimized bench method should be adopted; 2) When the ground surface inclination angle ranges from 10° to 20°, optimized bench method should be adopted and the support should be strengthened and timely monitoring should be executed; 3) When the ground surface inclination angle ranges from 20° to 30°, double side drift method should be adopted.

Key words: large crosssection tunnel, asymmetrical load, shallow cover, double side drift method, bench method, CRD method, optimized bench method, construction method optimization, mechanical analysis