关键词: 隧道中墙, 承载模型, 稳定性判据, 连拱隧道, 小净距隧道

Abstract: Conforming a reasonable middle wall of a multi-type tunnel and neighborhood tunnel is a difficult problem in tunnel design. The relation between middle wall stress and tunnel span, and middle wall width and tunnel depth was discussed. The stress in a middle wall under different middle wall widths and different tunnel depths was gained by a numerical method. The middle wall bearing weight correction coefficient K was confirmed by the recursive method. Therefore, a tunnel middle wall bearing weight model was set up. For the concrete middle wall of a multi-type tunnel, the uniaxial pressure intensity is its limited intensity. For a neighborhood tunnel, the limited intensity of the middle wall rock reinforced by prestress bolts was deduced on the basis of limit equilibrium condition. According to middle wall stress and limit intension, middle wall stability criterion was presented, of which its application in tunnel middle wall design was illustrated and validated by elastoplastic FEM result.

Key words: tunnel middle wall, bearing weight model, stability criterion, multi-type tunnel, neighborhood tunnel