Cracking behavior and deterioration of strength characteristics of silty clay under drying-wetting cycles

The strength of clay subject to drying-wetting cycles is influenced by multiple factors, rendering the prediction of its variation trend challenging. To investigate the variation in strength characteristics of cohesive soil subjected to drying-wetting cycles, silty clay was obtained from the Liangzhu archaeological site to prepare remolded soil sample. Subsequently, saturated consolidated undrained triaxial tests of control group, crack inhibition group, varied dry water content group and different overconsolidation ratio (OCR) group were carried out under different drying-wetting cycles. A thorough analysis of the test results reveals that the number of drying-wetting cycles does not affect the soil's critical state or phase transformation state. The strength of soil exposed to drying-wetting cycles is influenced by a combination of factors, including cracks formed during drying, overconsolidation, and hysteresis phenomenon. Specifically, cracks will destroy the integrity of the soil and thus reduce its strength, while overconsolidation and hysteresis contribute to an enhancement in soil strength. As the number of drying-wetting cycles increases, the prominence of cracks in the soil becomes more pronounced. Additionally, as the dry water content decreases, the deviatoric stress, excess pore water pressure, and effective stress path of soil continue to evolve in the direction of increasing OCR. This research enriches the study of the strength characteristics of clay under drying-wetting cycles, providing a foundation for the preventive protection of earthen sites in humid environments in geotechnical engineering.