Quantitative calibration method for the evolution of mechanical properties of gas-containing coal under mining-induced stress and microscopic failure evaluation

• Coal damage exhibits heterogeneous evolutionary characteristics under mining-induced stress, with the proposed damage characterization equation effectively determining critical damage thresholds based on irreversible deformation theory. • The three-parameter EXP function model is more suitable for characterizing the time-dependent damage process of coal under mining-induced stress. • A new characterization method for the coal brittleness evaluation index reveals an 800 m burial depth boundary for the coal brittleness index. • At the microscopic level, quantitative characterization of the correlation between peak stress and the average reduction in functional groups during mining-induced failure of coal at different burial depths is achieved, establishing a mapping relationship between laboratory parameters and field monitoring indicators for early warning of dynamic disasters.