Research methods : Taking construction of one metro station with shallow burying and surface excavation method as an example, the researches are done on the non-linear emulation of entire excavation and support processes for tri-span arch tunnel with double deck and pillar surface excavation structure by using ANSYS finite-element software as platform and adopting plane strain mode based on the theory of excavation and support for shallow burying tunnel.
Research results: The results of emulation calculation are basically correspondent to the site monitored data, so it can be used for instructing emulation research on stratum settlement and construction of similar tunnel.
Research conclusions: The influencing range on surface subsidence is about three times than the tunnel diameter, the max. settlement amount is 20. 75mm and the max. crown settlement is 29. 93 mm. For excavation of super long-span shallow burying tunnel, the ”group caves effect" is obvious and the control of surface crown settlements is key procedure with the support in the upper section in wall rock stratum with soft top and weak bottom. The blasting shock should be reduced for the lower section for controlling distortion. The settlement and subsidence values are different for excavation in different areas in the process of excavation and support of super long-span tunnel.
2007, Vol. 24 
