Experimental and simulation study on rail admittance characteristics in turnout area of urban rail transit

Abstract

In order to study the dynamic performance of rail-track turnout more widely and deeply, this paper established a 3D refined model of turnout and calculated the condensation characteristics of rail-track through the application of harmonic load sweep frequency analysis. The relevant calculation results are verified by field experiments. It was found that the rail pin-pinned resonance mode in the stock rail and switch rail close position, and jacking block and heel block would be suppressed. The change of switch rail profile caused gradual variation of switch rail admittance characteristic, which showed as the low-frequency original point admittance gradually decreases in the frequency-spatial distribution. The special fastener system of guardrail has limited lateral constraint on the guide rail, resulting in the lateral pin-pinned resonance mode of the guide rail not being significantly observed in the measured results. At the same time, the variation of the vertical bending first-order frequency of the rail was analyzed to analyze the change of the vertical support stiffness in the switch zone. The reliability and shortage of the three-dimensional (3D) track model in the switch zone were also analyzed by comparing the experimental data with the model calculation results.