• Water absorption in dolomite progresses through accelerated, decelerated, and stabilized stages, with pore count increasing and pore diameter initially decreasing then fluctuating.
• Microstructural evolution during water absorption shows mesopores first increase then decrease, micropores follow the opposite trend, and macropores remain near 0%.
• Dolomite strength softening under water influence occurs in three stages: a relatively stable stage, accelerated mesopore-dominated softening, and decelerated micropore-dominated softening.
• A uniaxial damage constitutive model based on Weibull distribution and Mohr-Coulomb criterion accurately captures water-affected dolomite behavior and is validated experimentally.