Research Into The Surrounding Rock And Supporting Structure Mechanical Behavior Of Tunnel In Slag Body Under The Influence Of Construction

Based on Fengjujiang tunnel, by adopting the method of finite element combining with the construction monitoring, the mechanical behavior of surrounding rock and supporting structure are studied in this paper. In concrete terms, this paper studied the mechanical behavior of surrounding rock and supporting structure under the influence of the tunnel construction which includes the tunneling footage, the construction process, the stable state of the tunnel after construction. The research result has a certain guiding significance for similar engineering where surrounding rock can not bear tensile stress.For the tunneling footage, first of all, the stress and the convergence of tunnel wall changing with the tunneling footage are researched. Then by comprehensive analysis of D-P principles, construction technology and construction safety factors can the tunneling footage is designed as less than or equal to 4.0m.For the research of tunnel construction process, this paper researched the law of the surrounding rock deformation and stress along with the dynamic change of tunnel construction, analyzed the law of the primary lining concrete deformation and stress, and revealed the relations between arch stress redistribution law and the tunnel excavation.For the research of the stable state of the tunnel, the prediction model of the mechanical behavior of the surrounding rock and primary support is obtained. Prediction model included the relationship between the displacement of surrounding rock(surface subsidence and the convergence of the tunnel wall), stress of surrounding rock (the first and the third principal stress) and the arch crown settlement. By means of forecasting model, based on the monitoring result, such as arch crown settlement or surface subsidence, then the deformation and stress of surrounding rock and primary lining can be forecasted.Besides, the paper also introduced the instruments, the method and the arrangement of sensors which were used when the stress of steel arch was monitoring. By analysis of monitoring results, and compared it with the theoretical value, theoretical value and the measured values are in good agreement.