Wall Rock Stability Analysis And Bolt-grouting Support Research Of Underpass Tunnel

Bolt-grouting support is the combination of bolt support and grouting reinforcement, it use grouting bolt. Bolt-grouting support adopts active reinforcement and support in underground cracking wall rock, it promotes the self loading capability of bolt-grouting wall rock, achieves the self stability of efflorescent cracking rock. The effect of bolt-grouting support in soft rock underpass tunnel is significant. The prospect of it is very extensive.Based on the related research findings of our predecessor and the expected underpass tunnel project in Qingdao, the natural factor and man-induced factor of wall rock stability is analysed in this article. The collapsing mechanics of tunnel wall rock, the stress distribution of tunnel wall rock, the stress criterion of wall rock and the research technique of wall rock stability are introduced. The mechanics analysis of bolt-grouting combination support and grouting reinforcement and combined action of bolt-grouting and wall rock are analysed in theory. Then, the determined method of bolt-grouting support parameter is prescribed. The mechanical calculation model of bolt-grouting wall rock is established, and the solving method of tunnel wall rock stress distribution regularity, the radius of limit equilibration area and displacement around the tunnel when the bolt-grouting wall rock in limit equilibrium state and in elastic state is represented. The numerical simulation calculation of bolt-grouting support underpass tunnel is done by ANSYS to research how much the bolt-grouting support influence wall rock stability and to optimize bolt-grouting support parameter. Then the parameter is optimized by the combination of orthogonal design and ANSYS. The best support scheme is determined and how much each factor influence the support effect is analysed.