Abstract: In the study, evolution laws of the roof structure were first investigated based on the principle of gob-side entry retaining formed by roof cutting and pressure release. Subsequently, stress and displacement transfer mechanisms of the surrounding rocks around a thick-seam fast-extracted mining face were discussed. Correspondingly, an active stability control approach for the entry surroundings was proposed by building a rock-steady structure using the upper strata of the main roof, bulking gangues at the gob and cutting cantilever of the entry roof. According to the deformation characteristics of the entry surroundings, we designed a series of cooperative supports with characteristics of constant resistance and pressure release. Particularly, the roof was supported by the constant resistance and large deformation anchor cable and pier-type unit. The gangue rib was stabilized by the sliding-type side wall prevention structure, self-advancing dynamic pressure bearing device and side wall prevention bolt with multi-resistances. Finally, industrial field tests were conducted in S1201 haulage entry of Ningtiaota coal mine for the first time. The results indicated that with increasing mining height and accelerating mining speed, a small amount of rotational deformation occurred inevitably owing to the movement of the main roof. Moreover, this deformation was not suitable to be supported compulsorily, and should be better coordinated by building a rock-steady structure artificially. The motion state of the gangues was closely related to the roof pressure, and thus an enhanced presplitting helped to reduce impacts of the dynamic mining pressure. Field monitoring results showed that the roof pressure first reached the constant resistance, and then the displacement tended to be stable. Finally, the rock-steady structure of the entry surroundings was formed. It was verified that the designed support structures could effectively coordinate with the movement of the surrounding rocks, and the indexes of the retained entry met requirements of the next mining panel.

Key words: thick coal seam, rapid mining, none-pillar mining, roof cutting and pressure release, entry surroundings control