School of Building Engineering, Hunan Institute of Engineering
School of Resources, Environment and SafetyEngineering,Hunan University of Science and Technology
Work Safety Key Lab on Prevention and Control of Gas and Roof Disas⁃ters for Southern Coal Mines,Hunan University of Science and Technology

To reveal the effect of pillar(core)in strength parameters,deformation characteristics and energy evolutionby environmental humidity values,the powder⁃crystal dolomite pillar from the -850 m middle section of the Chashan⁃ling mine was cored and produced into standard specimens. Based on the self⁃built confined space stable humidi⁃ty condition platform,the system simulation of on⁃site humidity was successfully carried out via steam method. The po⁃rosity,mass and size of the specimens were measured under dry,80%,90% and 100% RH conditions for 60 d respec⁃tively. Uniaxial compression tests were performed,combined with scanning electron microscopy and nuclear magneticresonance techniques to analyze the microstructure change laws and mechanical parameters such as strength and de⁃formation response characteristics. The results show that:① Increased environmental humidity causes dense and regu⁃larly arranged mineral particles to lose cements and develop blurred interlayer interfaces. Higher porosity with lossof mineral particles from softened contact surfaces leads to loss of specimen mass and reduction of size.② Environmen⁃tal humidity determines the limited failure mode of the specimen under loading. From tensile failure under dry condi⁃tions to mixed shear/ tensile failure under 100% RH, the macroscopic crack development on the specimensurface tends to increase with humidity value.③ Due to the “damage⁃linkage⁃invasion” effect of high⁃humidity expan⁃ding from the periphery to the center,the friction between dolomite fractures and mineral grains,as well as parameterssuch as elastic modulus and peak strength decrease,while Poisson’s ratio and peak point strain increase,which accel⁃erates the instability and deformation of dolomite pillar.④ Numerical simulation of humidity field water vapor corrosionwas conducted based on experimental data using particle flow software,and the interaction between micro⁃crack devel⁃opment characteristics and energy evolution of the model specimens under loading was analyzed.