Current numerical simulation studies on water intrusion failure characteristics of mudstone usually update the whole model mesoscale mechanical parameter as the calibration method

which cannot accurately reflect the differences in mechanical responses of specimens under different conditions. To improve accuracy

the simulation method should be updated to reflect the actual failure behavior of mudstone. Relative moisture content (RMC) is introduced to characterize the direct effect of mudstone under different humidification/heating conditions. The general model and the variant stratification (VS) model were constructed

and the mesoscale mechanical parameters were calibrated using the relationship between macroscopic uniaxial compressive strength and surface micromechanical strength to analyze the cementation failure characteristics of each specimen. The results showed that the macroscopic and microscopic strength of the specimens under different humidification/heating conditions varied significantly

and the uniaxial compressive strength weakened with the increase of RMC. The strength of the specimens showed an obvious linear correlation with the thickness of the VS model anisotropy. Compared with the general model

the number and percentage of tension damage cracks and shear damage cracks of the VS model were different

while the damage patterns under different water intrusion conditions were more consistent with the actual test results. Under different conditions

the general model changed significantly for the peak strain energy and cementation energy

while the VS model showed a gentle transition. By analyzing strength variation

damage patterns

and energy release in the simulated specimens

we revealed the mudstone cementation failure characteristics and validated the results for the VS-model specimens.