Cumulative strain characteristics of compacted soil under effect of freeze-thaw cycles with water supply

The cumulative strain characteristics of compacted subgrade soil were investigated by considering the effects of both freeze-thaw (FT) cycles and repeating loads. The soil samples were obtained from the seasonally frozen area in Northeast China. First, FT cycle experiments were carried out in an open system, following which dynamic triaxial tests were conducted on the same specimens. The influences of the number of FT cycles, dynamic stress, confining pressure, loading frequency, initial moisture content and compaction degree on the cumulative strain of the compacted soil were investigated systematically. The experimental results demonstrate that the cumulative plastic strain is positively correlated with the number of FT cycles, dynamic stress and initial moisture content, while the correlations between the cumulative plastic strain and the factors of confining pressure, loading frequency, and compaction degree are negative. Furthermore, the contribution rate of every factor on the cumulative plastic strain indicates that the dynamic stress and number of FT cycles have the significant effect on the cumulative plastic strain, while the initial moisture content effect is the weakest. Finally, a multifactor prediction model was established to evaluate the cumulative plastic strain of soil subjected to FT cycles with water supply, and the calculated results agree well with the experimental data, implying that the model proposed in this study is sufficiently reliable.