Study On Stability Of The Rock And The Liner Structure In The Loess Doubled-arch Tunnel

Loess has its own especial properties as one especial rock. There are many aspects which are needed to study in loess doubled-arch tunnel. With the development of tunnel support design theory, New Austrian Tunneling Method has become representation of modern support theory. Especially, because of the application of situ-monitoring measurement and its combing with theory analysis, New Austrian Tunneling Method has developed into a new design method---situ-monitoring method adapting to the characteristic of underground project and current technique degree. At present, situ-monitoring measurements, dynamic design and dynamic construction have become a kind of developmental trend in the design and construction of tunnel and underground engineering. In this paper, on the basis of Lishi doubled arch tunnel and the situ-monitoring data, this article analysed comprehensively stress and strain of the surrounding rock and stability of the whole tunnel. The principle and characteristic of the NATM monitoring are summarized in the article too. Based on the results of test, monitoring and past analyses of the tunnel, a generalized model for geology and construction process is established. By combination of computing schemes of orthogonal with the situ-monitoring displacement data as basic variable, the finite element method is used to back-analysis of properties of the surrounding rock. Then, with the results of back-analysis, the stability of the whole tunnel is analysed in a 3D FEM model. The results of the back-analysis and the numerical simulation are reasonable.