The Dynamic Monitoring Of Construction And Stability Analysis Of Surrounding Rock Of Shangguan Tunnel

With the rapid development of transport construction in china, a large number of highway tunnels are constructed. Because of many advantages comparing with the traditional Mining Method, the New Austrian Tunneling Method(NATM)is still a primary technology to construct highway tunnels in china at present. As one of three main pillars of the NATM, the construction monitoring is the key related with the safety of tunnel construction. Therefore, the study on the construction monitoring and stability analysis of surrounding rock of highway tunnel has theoretical and practical signification.Taking Shangguan tunnel in Hangrui Highway as an engineering practice,combining with the engineering geological conditions of the region, the monitoring scheme which has strong applicability is designed according to relevant code, which provides effective guidance for the field monitoring.The field monitoring data are analyzed by two-steps-method. Firstly, the uniform excel tables are used to preprocess the raw data, and the evolution of the monitoring data is researched. The errors are detected and solved by using the Unascertained Filtering method (UF). It is shown that many defects in traditional tracking measurement are overcome in the UF method and a good application effect is obtained. Secondly, correlation analysis, regression analysis and clustering analysis are carried out on the monitoring data by using Data Mining Technology. The four parts of the process in which surrounding rock deformation and pressure vary with time are made clear by clustering analysis, these provide an effective proof for determining the deformation controlling data and proper time for secondary lining and proposing early warning.The stability of surrounding rock of Shangguan tunnel is analyzed in the empirical method and the theoretical method. In the first method, a controlling criterion is built for the monitoring of the tunnel. In theoretical method, the regularity of the ratio of equivalent elastic modulus against load release the coefficient varying with time is derived by the analytic solution and the viscoelastic model of surrounding rock deformation is established, it is indicated that the ratios of equivalent Young's modulus against the load release coefficient decrease with time in ExpⅠmodel and the surrounding rock deformation varies in the inverse ratio of load release coefficient.The construction processes of the shallow-buried section at entrance of Shangguan tunnel are simulated by using the FLAC3D. The effects of the surrounding rock deformation which are related with different excavation methods and circulation footages are discussed. It is shown that the Bench Reservation Core Soil Tunneling method is more effective to control the deformation of surrounding rock than the Positive Benching Tunnelling method, and the footage which is not more than 2 m can be suitable for excavation under these geological conditions, but not a large one like 3m. Lastly, some useful conclusions are given by comparing the results of the simulation with the actual data.