Abstract: In order to identify whether the static expansion agent can crack the outburst coal seam in the working face of mine, the experimental model of cement tank was built. According to parameters such as the expansion hole, control hole, hole spacing and row spacing of the compacted outburst coal seam in the cement tank, three experiment schemes ofⅠ,Ⅱand Ⅲ were set up, and the cracked effect and its influencing factors in the schemes were analyzed under the action of static expansion agent. The experimental results show that two expansions of outburst coal samples in experiments all experience three obvious change processes-fracture development, propagation and interpenetration, that a large number of crack network along radial cross are formed between the drills, that the drill diameter, free surface and borehole layout all influence its cracking effect on the outburst coal samples, that in the same drilling experiment, the cracked effect of the plan Ⅲ is the best, and that with the other parameters keeping constant, as the number of the control hole increases, the crack length in the first expansive development will decreases.

Key words: static expansion agent, outburst coal, experimental model of cement tank, cracked effect, crack network