ABSTRACT
The coal mining in China is gradually from the shallow part to the deep part. With the increase of depths, the coal mechanics response characteristics show a significant difference with the shallow. Therefore, it is of great value to develop a constitutive model of coal damage which is suitable for different depths of in situ stress environment. Based on the theory of statistical damage, this paper develops a damage statistical constitutive model that can comprehensively consider the influence of depth on the whole process of deformation and failure of coal, to investigate the model parameters and damage evolution equations with the depth, further quantitative study of different depths of coal damage mechanism and failure mechanism. The results show that the constitutive model of coal damage considering the influence of depth is in good agreement with the experimental results and can reflect the deformation and failure process of rocks with different depths. With the increase of depth, the plastic characteristics of coal and rock become more and more obviously, the average macro-strength gradually increased and stabilized. Coal samples showed significant brittle rock damage accumulation process, and the deeper, the coal are damaged earlier and enter the cumulative damage stage.
