Abstract: To research the evolution laws of floor burst under dynamic loads, theory analysis and numerical simulation methods were used in this paper, to study the response characteristics of stress, displacement, et al, of roadway bottom coal under dynamic disturbance, and to reveal the causing reason and burst process induced by dynamic stress. The results show that the buckling failure and deformation will happen in the bottom coal seam, when the superposition of dynamic stress and high horizontal stress in floor reaches or surpasses the strength limit. In addition, the tensile stress, which is formed by the reflection of incident stress wave at the floor surface, causes spallation damage in the floor, and with the gradual enlargement of the damage range, the floor burst will be induced. Under the dynamic loading, the horizontal stress, vertical stress and stress difference firstly increase in a small extent, and then decrease substantially. At the same time, the scope of tensile failure zone and the vertical displacement increase subsequently. During the process, the concentration of horizontal stress in floor disappears gradually.

Key words: dynamic disturbance, floor burst, evolution law, numerical simulation