Research On Excavation Methods And Surrounding Rock Stability Of Wufeng Mountain Tunnel

This paper studied the karst stratigraphic tunnel in the Enshi area by different excavation methods,different cycle footage and different Mechanical Behavior of Surrounding Rock and Support Structure under Excavation of Step Length,Based on the mechanical characteristics and stability criterion of the surrounding rock in the tunnel excavation process in the Enshi City,Hubei Province.Based on the field monitoring and numerical simulation,the final value of the surrounding rock deformation predicted by gray theory is consistent with the numerical simulation results,which indicates that the research method is effective.The main research work is as follows:(1)Through the analysis of the monitoring data of the tunnel construction site,the change rule of the deformation of the surrounding rock with the excavation method is studied,and the best time of the second lining construction of the V-section surrounding rock section is obtained.By analyzing the surrounding area Rock deformation characteristics,and evaluated the effect of landslide treatment.(2)According to the theory of the displacement prediction of the surrounding rock prepared by the gray theory GM(1.1),the final convergence displacement of the deformation of the surrounding rock is predicted,and the stability of the surrounding rock is judged by the "release rate".This method has important reference value for judging the stability of tunnel surrounding rock.(3)The stability and the stability of the surrounding rock and the supporting structure under the excavation method are analyzed by numerical simulation.The results show that the tunnel V-level surrounding rock The construction of paragraph CD is better.(4)Based on the step excavation,the stress and deformation characteristics of the surrounding rock and the supporting structure are compared and analyzed,and the reasonable step length and cyclic footage are obtained.The height of the different steps is different from that of the different arch The deformation of the rock,the reasonable height of the step and the distance between the invert,and put forward a safe construction scheme.