Influence of Humidity State on Dynamic Resilient Modulus of Subgrade Soils: Considering Repeated Wetting-Drying Cycles

The service performance of subgrade depends on the dynamic resilient modulus (M-R) of subgrade soils. Meanwhile, due to complicated conditions such as rainfall infiltration, high temperature evaporation, and groundwater level fluctuations, it can be safely said that the humidity state and repeated wetting-drying (WD) cycles affect the M-R of subgrade soils .The object of this study is to conduct a series of dynamic triaxial tests after WD cycles to investigate the characteristics of the M-R under various factors. The main results are as follows: (i) the M-R decreased with the increase of deviator stress and rose with the growth of confining pressure; (ii) the humidification effect caused by the increase in moisture content attenuated the M-R; (iii) the accumulation of WD cycles damaged the M-R; however the decline rate was gradually retarded until it was stable with WD cycles 5 times; (iv) the satisfactory prediction model for the M-R of subgrade soils considering WD cycles was proposed and verified. It is expected that the findings can provide valuable contributions for road engineering.