LAUSR

To study the mechanical and deformation characteristics of ballastless track subgrade filled with micro-expansion fillers in a water-immersed environment, a physical model of ballastless track subgrade was constructed on a 1:2 scale with expansive andesite fillers. A water immersion test was carried out to model the soaking of the expansive soil foundation caused by rising groundwater. The swelling behaviors of the foundation and their influences upon the mechanics and deformations of the subgrade were analyzed. The lateral swelling pressure of the foundation and the heave of the subgrade obviously increased due to the water immersion, and the values were closely related to the overlying load and lateral restraint. The heave deformation of the double-line ballastless track subgrade showed significant nonuniformity along the lateral direction, causing the track slab to incline with a maximum inclination angle of 1.55×10-3 deg. The heave of the foundation caused a heave in subgrade, but this transferred heave was significantly attenuated. The attenuation rate of the heave at the midline of the track slab was up to 13.38%. The attenuation characteristic can be fully utilized for the anti-heave deformation measures of railway subgrade in expansive soil areas.