LOAD FOR SUBWAY-INDUCED FREE FIELD VIBRATION AND ANALYSIS METHOD

Utilizing measured acceleration data on rail, the load series on rail is obtained by a two-system model of subway train, considering rail-wheel Hertz contact and track irregularity. With the load series on rail and a simple model, a load series on tunnel invert is obtained. Meanwhile, a load series on tunnel invert is obtained by a longitudinal rail-tunnel-soil model and a wheel load series. These are the basic data for the analysis of subway-induced environmental vibrations. Then, the subway-induced environmental vibration is compared on two/three dimension models, considering the different influence of viscoelastic and viscous artificial boundaries. The proper two dimension model method and available tunnel load for subway-induced environmental vibration analysis are discussed. In addition, the applicable tunnel load for three dimension model is obtained. Finally, using a two dimension model and the tunnel invert load, the attenuation law on soil surface is analyzed and agrees well with measured data.