Wetting deformation prediction of compacted lateritic clay subjected to dynamic loading

Rainfall infiltration and groundwater level fluctuation cause the subgrade filler to be wetted, rendering the subgrade prone to accelerated permanent deformation under long-term traffic loading. However, the coupled effects of moisture variation and traffic loads on the wetting-induced deformation behaviour of compacted lateritic clay remain unclear. A series of repeated load triaxial tests was conducted to investigate the influence of moisture variation and dynamic deviatoric stress on the dynamic resilient modulus and accumulative plastic strain of compacted lateritic clay under both single-stage and multistage loading modes. Scanning electron microscopy and nuclear magnetic resonance tests were employed to analyse the evolution of microstructure and pore characteristics under different wetting conditions. The results revealed that the accumulated plastic strain increases while the dynamic resilient modulus decreases with increasing dynamic deviatoric stress, moisture content, and loading number. When the moisture content exceeds a critical threshold, the dynamic resilient modulus and critical dynamic stress decrease nonlinearly, resulting in rapid accumulation of plastic strain. Increased moisture content accelerates the degradation of interparticle bonding and alters the particle distribution of lateritic clay. Compared with the single-stage loading mode, the wetting-induced deformation is significantly reduced under multistage loading due to the influence of stress history. Prediction models for the accumulative deformation, dynamic resilient modulus, and critical dynamic stress of compacted lateritic clay are established, which effectively capture the relationship between the dynamic characteristics and moisture content. The research results contribute to evaluating the service performance of lateritic clay subgrades in humid and rainy regions. • The wetting deformation of compacted lateritic clay affected by stress history is compared. • The dynamic load envelope under permitted moisture conditions is proposed. • A prediction model of wetting deformation is developed for compacted lateritic clay.