Study on the dynamic constitutive model of coal at different depths in Pingdingshan mining area

The environment of deep in-situ occurrence is complex, and secondary dynamic disasters occur frequently. Exploring the dynamic constitutive models of coal at different depths is the foundation for deep resource development, which can help promote the safe and efficient mining of coal resources at different depths and reveal the mechanism of sudden dynamic disasters. Dynamic mechanical testing of coal at different depths of the Pingdingshan mine (China) was carried out using a split Hopkinson pressure bar system with confining pressure. On the basis of statistical damage theory, dynamic constitutive models of coal at different depths were explored, and the theoretical models were compared and verified using the experimental results. An expression relating to the infinitesimal element strength of coal and loading rate was derived, and the parameters σ 1 dp , E d , and ε 1 dp were determined. Inversion verification of the model showed that the experimental results agree well with the theoretical results prior to the peak stress. These research results are expected to be applied to the exploitation of deep resources, laying a foundation for the law of deep earth science and the construction of deep engineering. Article Highlights An expression for coal infinitesimal element strength that considers the rate effect is determined. A dynamic damage constitutive model of coal that considers occurrence depth is proposed. The influence of model parameters of coal at different depths on the dynamic constitutive model is discussed.