Experimental study on infrared changes in the progressive failure and stress distribution of bolted roadway

The thermal infrared (TIR) radiation in the deformation and progressive failure of coal roadway and the mechanism of thermo-mechanical coupling were investigated. The experimental achievement showed that the surface TIR temperature (TIRT) rose non-uniformly with the load increase before the stress peak and TIR radiation caused by stress concentration, shear band and bolted area, was much stronger and higher than that caused by stress relaxation, week friction and tensile fracturing. The bolted ranges were determined from the change ratios of TIR temperature of the different areas of the bolted surrounding rocks. The infrared thermal image anomaly appeared with the macro-cracks development in the progressive failure of bolted roadways, which reflected the spatial and temporal features of infrared precursor respectively. The infrared thermal image precursors were classified as TIRT increment region and TIRT constant region to disclosure the damage evolution and localization behaviours of bolted roadways.