A series of water vapor cycle experiments was conducted to examine the evolution of strength

deformation

and damage characteristics of red mudstone. The experiments included uniaxial compression tests and Brazilian splitting tests

utilizing acoustic emission (AE) and three-dimensional digital image correlation (DIC-3D) technology. The study concentrated on the evolutions in strength

deformation

and damage characteristics of red mudstone following different water vapor cycles. Results indicated that as water vapor cycles increased

the water content and volume of the mudstone showed irreversible accumulation

and the time required to reach water vapor equilibrium extended. Water vapor cycles caused reductions in compressive strength

tensile strength

elastic modulus

and shear modulus of the mudstone

leading to the proposal of an exponential degradation model for red mudstone. During uniaxial loading after different water vapor cycles

the failure mode of mudstone transitioned from overall shear failure to localized development of dispersed cracks. The evolution characteristics included delayed closure points of fractures

earlier onset of initial and damage stresses

extended compaction processes

shortened linear elastic deformation stages

and reduced ability of the rock to resist deformation.