Abstract:Mechanical effects of surrounding rock and composite lining are studied after small-distance tunnels located in soft strata achieves stability under different excavation manners with 3D fast finite difference software;and analysis is focused on the mechanical characteristics of bolt,shotcrete,the deformation and stress of surrounding rock characteristic points nearby the tunnel. The variations of bolt axial force and shotcrete moment with construction sequences in the recommended excavation manner are analyzed. The result shows that the excavation manner of the subsequent tunnel should be chosen carefully;and it has great influences on stress state of bolt and shotcrete of the former tunnel directly. The weak parts of composite lining and corresponding engineering measures are pointed out especially.