Study On Effecting Mechanism And Monitoring Method Of Existing High-speed Railway Tunnel Under Close-spaced Engineering

This paper depends on the "monitoring technology of high-speed railinfrastructure in the service state" project, which belongs to National HighTechnology Research and Development Program (863). Based on summarizedvarious kinds of close-spaced engineerings of tunnel structure domestic andoverseas, the impact mechanism and monitoring method of high-speed railwaytunnel are studied in a project case. The static and dynamic influence onhigh-speed railway tunnel with close-spaced excavation are carried out by usingmethods of numerical calculation, theoretical analysis and analog．The following main researches were gained:(1)The vibrations of high-speed train induced response in the structurearound, high-speed rail tunnel under the dynamic load will emerge non-uniformdeformation. The train vibration load and acceleration time-history curve aregained through the train-track dynamic interaction model.(2)Three kinds of close-spaced distance5m,10m,15m were used inFLAC3D model, the models are static excavated with different depth. High-speedrailway tunnel deformation mechanism in different types of close-spacedexcavation has been presented.(3)The high-speed train acceleration time-history is applied in staticexcavation model based on explicit dynamic analysis.High-speed rail tunnelinfluenced by the train vibration and close-spaced excavation has been analyzed,and the variation of tunnel displacement under additional vibration has been got.(4)According to the typical cross-section displacement in numericalcalculation, the tunnel numerical calculation displacement envelope curve isobtained by settlement curve empirical formula.The curve regards as the basis offull cross-section deformation speculation and set of monitoring points.(5)The monitoring points in the tunnel reasonably set up through high-speedrail tunnel deformation and stress analysis under close-spaced engineering.The tunnel monitoring system has been established and served as acomponent of high-speed rail infrastructure monitoring system in the state.