| The Chenggong tunnel of Kunming railway terminal is shallow and long-span under heavily expansive rock in seismic area,we need to have stress of excavation and expansibility of surrounding rock special testing during the construction.By learning the deformation law of the shallow and watery tunnel under heavily expansive rock after tunneling in the heavy earthquake region and the rock pressure change law of the supporting structure and long-time change law of the secondary lining,turn supporting parameter and change the construction methods based on experiments,which finally make sure the safety of constructing and running structure.The paper include several aspects(1)Field survey,protocol reinforced methods of tunnels construction and field process experiment and stability monitoring scheme.(2)Research the pre-reinforcement methods.do the experiment indoor from field sampling,research the expansibility of heavily expansive rock and swelling force with different water content,gain the expansibility parameters.Conduct shear strength test,get the expansibility mechanics index.Analyze mineral composition of heavily expansive rock by X-ray diffraction spectrum experiment.we conduct FEA according to the experimental parameters.(3)Field monitoring of tunnel stability.We monitor stability of tunnel in open cutting experiment zone and dark cutting,including deformation of surrounding rock,soil pressure,lining stress,body of tunnel deformation and subsidence of the earth’s surface.(4)Research optimal time of tunnel supporting.Make sure secondary lining opportunity based on monitoring data and analysis.Research construction technology and parameters of expansive rock tunnels and obtain heavily expansive rock tunnels construction integrated technology.(5)Numerical analysis of tunnels stability.Simulate tunnels’ stress and strain in process of excavation and convergence compared with monitoring results.Summarize law in order to guide tunnels design and construction. |
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