Dynamic compressive failure of coal at different burial depths

Abstract

Dynamic disasters frequently occur in deep coal mines, where coals and rocks are under high in situ stresses. To reveal the failure mechanism of deep burying coals, the specimens were made of buried coals at a depth of about 1 km. An improved Kolsky bar was applied to conduct the dynamic compression experiments subjected to different hydrostatic pressure i.e., 0, 5, 10, 15, and 20 MPa for simulating in situ stresses corresponding to depths of 0, 200, 400, 600, and 800 m. The findings demonstrate that the dynamic compressive strength of coal at a specified depth is rate-dependent. And the dynamic strength is positively correlated with the burial depth at a given loading rate. Moreover, a Mohr–Coulomb strength criterion for coal under dynamic loadings that considers the effect of depth is established, and the model describes the experimental results well.