<p>This paper investigates the degradation of resilient modulus and microstructure of geopolymer-solidified and cement-treated high plasticity clay subjected to wet-dry cycles. Periodic half-sine wave cyclic triaxial tests are performed to examine the deviator stress-strain behavior, from which the degradation of resilient modulus is identified. Two-stage degradation mode is demonstrated: the rapid reduction in the resilient modulus is recorded at first cycle, followed by an asymptotic trend up to 7th wet-dry cycles. A unified framework is proposed to capture the nonlinear degradation mode, where the damage rate and potential were considered as the key parameters of the proposed model. The higher damage rate and potential are shown in the untreated specimen compared to the chemically improved specimen, indicating the enhancement of resistance to environmental degradation by additives. The mineralogical modification after treatment confirms a considerable amount of calcareous binder materials, inhibiting the slaking of the clay matrix, forming a dense microfabric and a stable pore structure. Such a microstructural adjustment is elucidated in detail at the microscopic scale by conducting a combination of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and mercury intrusion porosimetry (MIP) tests.</p>