Intensification Effect of Aerodynamic Load in Lining Cracks of High-speed Railway Tunnel
Research purposes:Frequent falling blocks in high-speed rail tunnels can cause serious economic losses and even casualties.The intensification effect of high-speed train aerodynamic load in the crack may be an important reason for the crack expansion and eventually the formation of falling block.In order to prevent falling block accidents in high-speed railway tunnels and strengthen tunnel disease control,the intensification effect of aerodynamic load in lining cracks should be studied.In this study,based on Fluent software,finite volume method(FVM)and Pressure-Based solver are used to simulate the aerodynamic pressure in crack space by unsteady viscous k-ε turbulence model considering the compressibility of air.Using this model,the temporal and spatial characteristics of the aerodynamic loads of circumferential,inclined and longitudinal cracks are discussed.The spectrum characteristics of aerodynamic pressures are analyzed,and the effects of crack length,width,depth and vehicle speed on the aerodynamic loads of crack surface are analyzed.Research conclusions:(1)The pressure wave enters the circumferential crack space instantaneously,and the pressure wave enters the inclined and longitudinal crack space procedurally.(2)The peak value of circumferential crack pressure is 5.32 times of the input pressure.The peak pressure values of inclined and longitudinal crack are only 79.5%and 64.9%of the corresponding values of circumferential crack,respectively.(3)The PSD of the aerodynamic pressure of the circumferential crack is 4.04 and 1.54 times higher than the value of longitudinal and inclined cracks on average.(4)The crack length and width have limited influence on the peak pressure of crack surface.The crack depth and the peak pressure meet the linear function relation,and the speed and the peak pressure meet the power function relation of 2.303 3.(5)The research findings can provide references for the design of high-speed rail tunnels,and the assessment and repair of cracks within the tunnels.
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