Workface Stability of Shield Tunnel Considering Arching Effect

Abstract:

The minimal earth pressure on the shield tunnel face can be calculated using a new method proposed in this paper. This method takes into account the arching effect in loosening soil and the friction between cutter and soil. It is found that the distribution of the minimal earth pressure is not uniform, which is assumed by the existing methods, but parabolic. The parameters, including soil cohesion, soil friction angle, the friction angle between cutter and soil and the cover to diameter ratio, have significant influence on the minimal earth pressure. The stability of workface can be enhanced by decreasing the friction angle between cutter and soil. Finally, the results of the proposed method agree quite well with those reported in other literatures based on the existing methods.