Meso-experimental research on sandstone failure behavior under thermal-mechanical coupling effect

It becomes more and more important to study and understand the deformation and strength properties of rocks to meet the increasing demands of deep mining and nuclear waste disposal.The paper mainly studied different temperature effects on deformation and failure characteristics of sandstone through meso-experiment.Experimental results indicated that the tensile strength increased with the temperature increment from 25 ℃ to 15 0 ℃,and decreased with the temperature increment from 150℃ to 30 0℃.The similar phenomenon has not been reported in the previous literatures.Also it differs with the most macroscopic experimental results.The paper analyzed the possible reasons in detail.Also the experimental results of macroscopic fracture map and nominal stress-strain curves indicated that the temperature had a strong influence on the deformation mechanism of sandstone.The fracture mechanism had the tendency which transforms from brittle fracture mechanism in low temperature to ductile fracture mechanism in high temperature.