Laboratory Study on the Water-Heat Behavior and Freeze-Thaw Deformation of a Composite Embankment considering Rainfall in Seasonally Frozen Regions

Based on the similarity theory, a laboratory experiment considering the influence of rainfall was performed to study the water-heat behavior and freeze-thaw deformation between the normal embankment and the composite embankment, consisting of permeable geotextile, crushed-rock interlayer, and waterproof geomembrane. The results showed that due to the existence of crushed-rock interlayer, the effective frozen depth of the composite embankment was smaller than that of the normal embankment. In the rainfall period, because of the drainage function of permeable geotextile and a crushed-rock layer, the water content of soil upon the crushed-rock of the composite embankment was lower than that of the normal embankment. Meanwhile, the waterproof geotextile blocks the upward migration of water in the deep soil, which only changes under the freeze-thaw cycles. Therefore, compared with the normal embankment, the composite embankment can reduce the frost heave and uneven deformation of the embankment under the condition of rainfall infiltration, effectively avoiding the formation of longitudinal cracks of the embankment.