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Coal Engineering ›› 2023, Vol. 55 ›› Issue (9): 28-33.doi: 10.11799/ce202309006

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Surrounding Rock Control Technology of Roadway by Roof Cutting in Double Layer Close Distance Hard Strata

  

  • Received:2023-01-08 Revised:2023-03-16 Online:2023-09-20 Published:2023-11-23

Abstract:

Aiming at the problem of large deformation of gob side entry retaining surrounding rock caused by unreasonable roof cutting parameters in the double layer close distance hard strata. Through in-situ monitoring, theoretical analysis and discrete element numerical simulation, taking the 090109 headentry of Baigou Coal mine as the project background. The characteristics and mechanism of ground pressure behavior of gob side entry retaining with the double layer close distance hard strata are expounded. The necessary conditions for maintaining the stability of roadway surrounding rock are analyzed. The reasonable roof cutting height, cutting angle and roof strengthening support technology are put forward. The results show that the synchronous bending and sinking of the double layer close distance hard strata in the goaf is the main reason for the large deformation of the gob side entry roof and floor. Roof cutting not only weaken the role of the transmission force from the goaf roof to the gob side entry surrounding rock, but also increase the crushing expansion space of the interlayer soft rock, and increase the support strength of the upper hard stratum. It is a necessary condition to control the roadway surrounding rock stability that the collapse of interlayer soft rock strata after roof cutting can fill the goaf. Based on the actual conditions, it is determined that the cutting height and angle of 090109 headentry are 6m and 15° respectively. Compared with the original roadway surrounding rock control scheme, the in-situ monitoring show that the roof and floor displacement is reduced by 35.3%, solid coal wall displacement is reduced by 49.9%, and the surrounding rock stable distance behind the working face is reduced by 55.2%, after combining the roof anchor cable reinforcement support technology. The research results provide a feasible basis for the roadway by roof cutting in the double layer close distance hard strata.

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