Coal Engineering ›› 2022, Vol. 54 ›› Issue (5): 32-39.doi: 10.11799/ce202205006

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Failure mechanism of floor heave and reinforced support techniques in deep gob-side entry retaining with cutting roof

  

  • Received:2021-05-19 Revised:2021-11-20 Online:2022-05-13 Published:2022-05-23

Abstract: In order to solve floor heave and frequent maintenance problems of gob-side entry retaining for cutting roof in deep coal mines, the stress environment changes of gob-side entry retaining were analyzed combined with the abutment pressure of mining-induced surrounding rock. Based on the Slip-line field theory, the mechanics models of floor heave in gob-side entry retaining under different stress stages were established, and the failure mechanism of floor heave under different stress stages were studied. At last, the supporting test of floor were carried out for reinforced support. The results show that the stress environment changes of gob-side entry retaining can be divided into three stages: before roadway cutting roof, the primary mining after the roadway cutting roof and the gob-side entry retaining. The floor in three stages present symmetrical floor heave with small deformation, asymmetric deformation with floor heave higher in longwall face side than that in solid coal side, and asymmetric large deformation and failure with floor heave higher in solid coal side than that in goaf side. With the increase of mining depth, the minimum support loads of floor in gob-side entry retaining increases. And the floor heave rate of the restricting reinforced support at floor area decreases about 33.3%, the floor heave can reduce 804mm, and it is most suitable for controlling the deformation and failure of floor in the gob-side entry retaining under cutting roof in deep coal mines.

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