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Coal Engineering ›› 2023, Vol. 55 ›› Issue (7): 102-109.doi: 10.11799/ce202307017

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Mechanisms and control techniques for the occurrence of floor heave in neighboring roadways under the influence of mining

  

  • Received:2023-01-31 Revised:2023-03-09 Online:2023-07-20 Published:2025-04-07

Abstract:

The triple soft coal seam bottom lane with double lane arrangement faces multiple mining influences and is often subject to greater damage and deformation, accompanied by serious floor heave disasters. In order to investigate the mechanism of the occurrence of floor heave in the lower section of the working face with double lane arrangement and propose the corresponding control technology, this paper takes 3309 transport lane of Hancheng Sangshuping No.2 shaft as the engineering background, establishes the mechanical model of the neighboring lane bottom slab in the mining area through Rankine soil theory, and adopts FLAC3D finite difference program to simulate the distribution law of mining stress and the range of plastic zone when the working face with double lane arrangement is retrieved, the research results show that: (1) The adjacent workings began to dropsy at 210m in front of the workings and the rate of increase of the dropsy displacement increased at 40m in front of the workings, with the maximum dropsy amount reaching 662mm. (2) According to the stress equation of the rock of the roadway floor calculated by the mechanical model, we can get that the damage of 3309 roadway floor is linearly related to the stress concentration coefficient of the two gangs of the roadway, and the slope of the coal pillar gang stress concentration coefficient K' axis Δ1 is 6.520. (3) According to the numerical simulation results, the depth of the plastic zone of the bottom slab of 3309 working face is maintained at about 3m, and the maximum vertical stress of the coal pillar behind the working face reaches 44.5MPa due to the influence of mining, which leads to the penetration of the plastic zone of the neighboring roadway gang. Based on the mechanism of the occurrence of the floor heave in the neighboring roadway in the mining area, the pre-cracking top cutting and pressure relief technology was proposed to control the deformation of the roadway in the No. 2 shaft 3309 transport roadway, and good results were achieved to ensure the normal production of the mine and the safety of personnel and equipment. Keywords:mechanisms of floor heave occurrence; floor heave control; blast pre-cracking topping and pressure relief; numerical simulation; adjacent roadway

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