Research For The Stability Of Surrounding Rock & Supporting Structure For Super Long-Deep Buried Highway Tunnel

In the process of tunnel construction, the reliability of surrounding rock and supporting structure is the most important problem we focus on, and more and more researchers pay more attention to this field, it is also the key component of the tunnel construction. There are so many essential plans and designs of the long deep road tunnels in the middle and west of our country, which are shortage of construction experience and research in the past. So the significance of the research of reliability of surrounding rock and supporting in the long-deep road tunnel is very important for the construction of the tunnel.On the base of the research results of the previous researchers, a lot of references and experiences were used as an important source in this thesis. According to the Caishenliang tunnel in the highway from Hangzhou to Lanzhou, the research of surrounding rock and supporting structures were carried out through protracted and unremitting monitoring in the constructing field. Elementary estimation of the rank of rock was obtained from observation of the excavated surface. In the meantime, the stress and strain conditions of the surrounding rock and supporting structure were analyzed through the monitoring of the deformation of surrounding rock as well as the stress of anchor bolts, shotcreting, flange beams and inside lining. And then, by comparison to the results of the observation, the numerical analyses of the stress situation, deformation properties and supporting structures of the typical sections of the fourth-class and fifth-class rock were made by the geotechnical analysis software Tongji-Shuguang in order to analyze the reliability of the tunnel. From the results of the analysis above, the space-time effect has been obtained as well as the stress of the surrounding rock, the axial force of anchor bolt and steel shotcrete, the internal force of inverted arch and inside lining. According to the results of monitoring and numerical analysis, the stress properties of surrounding rock and supporting structure in the long-deep tunnel have been analyzed, when it is in the high initial stress and any special geological condition. In addition, on the base of the numerical analysis, the supporting structure form of the Caishenliang tunnel has been optimized. Step method has been used to excavate the tunnel in the bad surrounding rock condition of the long-deep tunnel in order to improve the reliability of the surrounding rock and the whole tunnel structure, while in the good surrounding rock condition full section method has been used to make the stress of the supporting structure much more well-distributed and reasonable.Through the monitoring and numerical analysis of the tunnel, the engineering practice, theoretical analysis and some different analytical methods have been used by the author to analyze the reliability of the surrounding rock and supporting structure in the long-deep tunnel. And some significative conclusions have been obtained based on the analyses above, which can give a dependable foundation and recommendation of the parameter optimization of the design for long deep tunnel.