Stability analysis of surrounding rock and supports in large-span loess tunnel using the convergence-confinement method

The stress patterns of the loess tunnel are complex because of special engineering characteristic of loess.For the big excavation cross section,the CRD or bench method is often used under tunnel construction.The common methods of displacement monitor have some problems.The convergence-confinement method is a useful theoretical tool for stability analysis of rock mass on tunnel construction.Although the method cannot accurately reflect mechanical characteristics and processes of the tunnel construction,the characteristic of interaction and dynamic effect between rock and support can be found out.Based on the field monitor data,this paper analyzed the stability of the surrounding rock and safety of initial support by convergence-confinement method.The results provide a reference for the following tunnel construction.