The variation in soil moisture can lead to unfavourable deformation of highway embankments, threatening their long-term stability under seasonal groundwater level fluctuations and frequent changes in evaporation and precipitation. This paper conducted unsaturated soil triaxial tests to examine soil water retention and volumetric deformation behavior during wetting-drying cycles. The results show that soil water retention decreases with increasing wetting-drying cycles, particularly in the low suction range from 0 to 100 kPa, where gravimetric moisture content (GMC) declines sharply. With more wetting-drying cycles, the soil's capacity for volumetric deformation diminishes. The soil has a loose soil structure and is more prone to plastic deformation. Furthermore, three soil water retention models, the Gallipoli, Tarantino, and Hu models were employed to analyse soil's hydromechanical behaviours and evaluate the effect of wetting-drying cycles. It was found that Tarantino's model used only three fitting parameters, which were more concise and maintained a good fitting effect. This study clarifies soil-water retention and volumetric deformation behavior during wetting-drying cycles, which is essential for effective water control in subgrade construction and operation.

This study conducted five centrifuge model tests to investigate the deformation characteristics of the Geosynthetics Reinforced Soil (GRS) abutments under vertical loads, considering the setback distance ab and beam seat width B as two major influencing factors. Test results show that a linear correlation existed between the maximum lateral facing displacements DL and the maximum settlements at the top of the GRS abutments Dv. The ab and the B had different effects on the deformation characteristics of the GRS abutments as well as the relationship between the DL and the Dv. The total volumetric strains of the GRS abutments were smaller than 0.3% for all the cases investigated in this study, indicating that it was reasonable to use the assumption of zero-volume change for the deformation calculation of the GRS abutments. This study proposed an improved semiempirical method to describe the relationship between the DL and the Dv. Centrifuge test results and data collected from the literature were used to validate the improved method. It was concluded that the improved method had the advantage of considering the effects of the ab and the B separately and therefore significantly improved the prediction accuracy of the deformations of the GRS abutments.

Contemporary geotechnical engineering practice encompasses design and construction of thermo-active geostructures or structures which would encounter thermal cycles throughout its service life. Therefore, understanding the effect of temperature on soil mechanical properties becomes inevitable. Being a complex and coupled phenomenon it has been quite challenging for the researchers to study experimentally and theoretically the thermo-mechanical behaviour of fine-grained soil. Nonetheless, there are numerous studies which contribute significantly to gain insight about thermo-mechanical behaviour of soils. Incidentally, till date, on this arena of research, no comprehensive review, which provides a holistic development of the subject and its connection with the field application, is available. The prime objective of the present study is to critically appraise the state-ofthe-art understanding on thermo-mechanical behaviour of fine-grained soils through a comprehensive literature review. Moreover, this paper also describes the concept of thermo-elasto-plastic strain and thermal creep behaviour of fine-grained soils.