Static compressive mechanical properties and disturbed state concept-based theoretical model of gypsum rocks with coupled influences of wet-dry cycles and flow rates

• Wet-dry cycles cause logarithmic declines in elastic modulus, cohesion, UCS, and internal friction angle of gypsum rocks. • Higher flow rates accelerate the mechanical deterioration induced by wet-dry cycles, as confirmed by NMR microstructural analysis. • A disturbed state concept (DSC)-based constitutive model accurately predicts nonlinear compaction, peak stress, and post-peak behavior. • The findings offer practical implications for stability assessment and design of underground structures in gypsum-rich strata under complex water conditions.