To prevent the cracking of silty clay under cyclic wet-dry cycling (W-D), which leads to the increase of deformation and strength attenuation of silty clay, microencapsulated phase change material (mPCM) was used to improve it. The deformation and strength characteristics of silt with different dosages (1 %, 2 % and 4 %) of mPCM and their changing patterns were analyzed and studied by indoor compaction test, crack observation test, consolidation test and straight shear test, and compared with silt without modifier. The results showed that with the increase of mPCM dosage, the optimum water content of silt and the maximum dry density decreased. A 2 % dosage of mPCM inhibited the development of silty clay cracks, reduced crack width and deformation, and increased the compression modulus of the soil samples by nearly 2.3 times. Under dry and wet cycling conditions, the cohesion decay of silty clay is greater than the angle of internal friction. The addition of 2 % mPCM significantly increased the shear strength of silty clay, cohesion by nearly 2.1 times, and internal friction angle by 1.4 times. The mPCM inhibits crack development mainly by regulating the internal temperature field of soil samples, thus improving soil strength. This study provides a reference for inhibiting soil cracking from a new temperature perspective.

In practical engineering applications, cured lightweight soils are commonly used as roadbed fillers and subjected to intermittent and discontinuous traffic loads. However, previous studies primarily focused on the effects of continuous loading on the mechanical properties of cured soils. To address this knowledge gap, this study investigated the deformation characteristics of fiber-reinforced cured lightweight soils under dry and wet cycles and intermittent loading. Dynamic triaxial tests with varying intermittent ratios and numbers of dry and wet cycles were conducted to assess the influence of these factors on the accumulated plastic strain of fiber-reinforced cured lightweight soils. Based on the test results, a prediction model was developed to estimate the accumulated plastic strain of the cured soils under intermittent loading. The findings indicated that the interval length has a dampening effect on the accumulated plastic deformation of the soil, thereby improving its ability to resist deformation. Additionally, the accumulation of plastic deformation gradually increased with the number of wet and dry cycles but eventually stabilized. In multistage loading, the accumulated plastic strain displayed a rapid increase and stabilization trend similar to that in observed the first loading stage. However, the magnitude of the cyclic dynamic stress ratio determines the deformation at later loading stages. Finally, an improved exponential model was used to establish and validate a prediction model for the cumulative plastic strain of the fiber-reinforced cured lightweight soil under intermittent loading (single and multistage). This prediction model provides important guidance for the practical application of fiber-reinforced cured lightweight soils in engineering projects.