地铁振动下的轨道结构应力波传播特性OA

During the operation of a subway,vibrations generated on steel rails propagate in the form of stress waves along the path:rail-rail pad-sleeper-ballast-tunnel-soil.In order to investigate variations in the fundamental characteristics of stress waves along this propagation path,we constructed an indoor model of a subway tunnel with steel rails.A Laser Doppler Vibrometer(LDV)was used to measure stress wave signals at different locations of the experimental model,and a scanning LDV was employed to capture the real propagation process of stress waves on different surfaces of the steel rails.Finally,the finite element simulation software LS-DYNA was utilized to perform a comparative analysis of the changes in wave field characteristics during stress wave propagation from an image perspective.The research results indicate that the stress wave signals generated by the wheel-rail interaction on the steel rails are mainly characterized by low-frequency signals ranging from 25 to 400 Hz and high-frequency signals at 1 400 Hz.Conversely,the stress wave signals propagating into the soil primarily consist of low-frequency signals ranging from 25 to 200 Hz.A comparison between the measured data and test results of the experimental model demonstrates that the steel rail model exhibits dynamic performance consistent with the actual subway tunnel.The analysis of signal data and wave field contour maps both indicate that the high-frequency components of stress waves attenuate most rapidly during propagation from the steel rail to the concrete sleeper,exhibiting the lowest signal energy transfer rate.The comparison of stress wave fields from LDV measurement and computer simulation intuitively validates the accuracy of the simulation method from an image perspective.Additionally,this study suggests that LDV measurement results can serve as an alternative to computer simulation results for investigating wave fields in complex media and models.