| Based on research conclusions for stability of surrounding rock during tunnel excavating around home and overseas, together with the construction project of Jiangyuanling tunnel, the mechanism properties of surrounding rock and supporting structures were studied systematically by theoretic methods and numerical simulation during tunnel excavating.1) The deformation of surrounding rock had been measured and monitored in field. The measuring work contented convergent deformation of surrounding rock, surrounding rock pressure and earth surface displacement. Then, the measured and monitored data were analyzed systematically.2) Calculation models of tunnel from K34+130 to K34+170 were established by FEM(ADINA 8.1), the elastic-plastic method and the yield criterion of Mohr-Coulomb were used during this process, Excavation by steps and support construction of the tunnel were 3D simulated. The displacement and stress figures on each excavate and supported phases were obtained. By analyzing these data, the displacement and stress rules of surrounding rock and supporting structures in the tunnel were obtained during the excavation process.3) By comparing the measured data in field with finite element numerical simulation results, the stability of surrounding rock and the safety of supporting structure were evaluated. The results of contrast study shows that the test results were agreed with the calculated tests fully. So, the theoretical methods and model parameter were logical, which could respond mechanism and deformation characters of supporting structure during the excavation process preferably. This study production could provide theoretic basis for the safe and well-off tunnel construction. |
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