Ground vibration test of the Zhengzhou-Xi’an high-speed railway and analyses of the vibration isolation trench effect

The dynamic load of high-speed railway train can cause environmental vibration problems. In order to study the environmental vibration effect caused on the viaduct bridge section and embankment section by high-speed train, the field test of the Zhengzhou - Xi’an high-speed railway is carried out, and the ground vibration characteristics and attenuation law of viaduct bridge section and embankment section are compared and analyzed. The test results show that the vibration response of the embankment section is greater than that of the viaduct bridge section, and the attenuation effect in the near-field area of the viaduct bridge section is higher than that in the near-field area of the embankment section. There are multiple rebound increases in the process of vibration propagation, and the ground vibration rebound of the embankment section lags behind that of the viaduct bridge section. The increase rate of secondary rebound in the viaduct bridge section and embankment section is significantly greater than that of primary rebound. The attenuation of Z vibration level with the distance conforms to the law of logarithmic attenuation. The Z vibration level attenuation formula in the loess area is obtained by fitting, and the maximum deviation appears in the rebound increasing area. The infinite element-viscoelastic coupling boundary is introduced to establish a 3D track-soil-vibration isolation trench numerical model of the embankment section. The influence of vibration isolation trench on vibration reduction and isolation of high-speed railway is analyzed. The results show that the vibration isolation effect of empty trench on the medium and high frequency (30 - 60 Hz) vibration wave is more obvious than that of low frequency (1 - 20 Hz), and it has the function of low-pass filtering. The vibration isolation effect of empty trench is better than that of filled trench, but soft materials can be filled in the trench considering the stability of trench walls. The research results can provide references for the design of high-speed railway and the evaluation and control of environmental vibration.