Coal Engineering ›› 2025, Vol. 57 ›› Issue (9): 91-99.doi: 10. 11799/ ce202509013

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Mechanism and Control Strategies of Floor Heave in Roadways Under Repeated Mining Disturbances in Fully Mechanized Top-Coal Caving Mining

  

  • Received:2025-05-30 Revised:2025-07-04 Online:2025-09-10 Published:2025-10-13
  • Contact: yang zhen E-mail:yzhen202505@163.com

Abstract:

Abstract: In the mining process of double-entry layout working faces, roadway surrounding rocks are significantly affected by repeated mining disturbances, leading to severe ground pressure manifestations. To address this issue, the 226up03 return airway at Huangyuchuan Coal Mine was selected as the research object. Field measurements, numerical simulations, and theoretical analysis were employed to investigate the stress evolution characteristics of roadways under repeated mining disturbances, the failure mechanisms of surrounding rocks, and the formation mechanism of floor heave. Control strategies for mitigating floor heave were also proposed. The results indicate: ① Field measurements of surrounding rock deformation reveal that the influence of primary mining on roadway disturbance is limited in scope. During the initial mining phase, the roadway remains stable overall, with no significant deformation or failure observed. However, secondary mining exhibits phased strong disturbances, causing severe deformation of the roof and floor within a 40 m advanced range, with the affected zone extending up to 120 m ahead of the working face. ② The evolution of plastic zones in surrounding rocks under repeated mining was clarified: After roadway excavation and stabilization, rock failure is primarily concentrated in the floor. Minor disturbances occur during primary mining, while secondary mining intensifies the expansion of plastic zones in the floor, resulting in asymmetric failure patterns dominated by an inverted "7" shape. ③ The failure mechanism of floor heave under repeated mining was elucidated: The deflection angle of principal stress controls the expansion direction of plastic zones, the magnitude of maximum principal stress determines the failure range, and the presence of weak floor strata exacerbates stress redistribution, ultimately inducing floor heave. ④ Floor heave control strategies were proposed and implemented: By installing 7 m advanced supports ahead of the working face and reducing the spacing between each unit support by 400 mm, field tests demonstrated enhanced coordination between the floor and supports, improved surrounding rock stability, and ensured safe coal recovery in the working face.

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