Soil-Water Characteristics and Dynamic Responses of Compacted Clay with Different Moisture and Temperature Histories

This study compares the microstructure, soil-water characteristics, accumulative plastic strain (εp), and resilient modulus (MR) of a compacted Heilongjiang clay. Specimens were imposed with three different moisture (wetting-drying, WD) and temperature (freeze-thaw, FT) histories (i.e. WD-FT, FT-WD and interlaced FTWD histories). Experimental results showed that (i) after moisture-temperature (M-T) actions, structural pores develop while textural pores shrink, which leads to reduction in water retention capacity and increase in desaturation rate. After M-T effects have stabilized, the microstructure and soil-water characteristics of specimens with different M-T histories become similar; (ii) at high moisture content (w) condition, the εp and MR are more sensitive to moisture changes (including w and suction, s). After FT cycles, the εp becomes more sensitive while the MR becomes less sensitive to moisture changes; (iii) after M-T effects, the MR-s relationships are nonlinear while the MR-w relationships are linear. The different M-T histories did not generate differences in the εp and MR when the M-T effects have stabilized; (iv) a model based on the unsaturated soils mechanics was used to rationally predict the variation of the MR with w and s for specimens with different M-T histories.