ABSTRACT
Under the influence of the wet-dry cycles, the dynamic properties of expansive soil in railway subgrade tends to be more complex. In this study, the effects of wet-dry (WD) cycles, dynamic loading and moisture content are investigated by dynamic triaxial tests. The results show that these factors have significant effects on the dynamic properties of expansive soils. In the different deviator stress conditions, soil deformation shows different trends. The expansive soil was stable as the deviator stress was less than the critical dynamic stress. Conversely, the expansive soil was destroyed as the deviator stress exceeded critical dynamic stress. With the increase of wet-dry cycles, the critical dynamic stress decreased and the accumulated strain increased. The cumulative deformation increased rapidly when the wetted time was from 0 to 1, and the increase rate slowed from 2 to 3. The results reveal the cumulative deformation law of expansive soil under the combined action of repeated wetting and dynamic load. It is expected to provide theoretical support for the construction and long-term performance evaluation in the expansive soil area.
