工作面开采过程中不同因素对煤壁失稳的影响研究

Research on Influence of Different Factors on Coal Wall Instability During Mining Process of Working Faces

  • 摘要: 为研究工作面开采中不同因素对煤壁失稳的影响,以赵固一矿11051工作面上分层为工程背景,通过FLAC3D模拟分析了采高、煤层内摩擦角及锚杆支护对煤壁稳定性的影响。研究表明:随采高增加,煤壁前方垂直应力集中区逐渐向下向前转移且面积扩大,当采高由3.5 m增至4 m时,塑性区破坏程度显著加剧,其中剪切破坏比例明显上升,煤壁上部拉变形量由18.2 cm增至35.6 cm,片帮风险升高;煤层内摩擦角由20°增至40°时,垂直应力最大值由80.0 MPa升至104.8 MPa,集中区上移,塑性区范围从26 m缩减至6 m,煤壁水平变形量显著降低,稳定性增强;锚杆支护对垂直应力影响极小,但可将塑性区范围控制在煤壁前方约2 m内,水平变形最大减小239 mm,有效降低片帮风险,现场应用后片帮频次减少50%以上,达到了有效降低片帮风险的效果。

     

    Abstract: In order to explore the influence of different factors on coal wall instability during working face mining, taking the 11051 working face upper layer of Zhaogu No.1 Mine as the engineering background, the influences of mining height, coal seam internal friction angle, and anchor rod support on coal wall stability are analyzed through FLAC3D simulation. The research shows that with the increase of mining height, the vertical stress concentration zone in front of the coal wall gradually shifts downwards and forwards, and the area expands, when the mining height increases from 3.5 m to 4 m, the failure degree of plastic zone significantly exacerbates, among them, the proportion of shear failure is significant increased. The tensile deformation amount of the upper part of the coal wall increases from 18.2 cm to 35.6 cm, and the risk of wall caving is increased; When the internal friction angle of the coal seam increases from 20° to 40°, the maximum value of vertical stress is improved from 80.0 MPa to 104.8 MPa, the concentration zone shifts upward, the range of plastic zone is reduced from 26 m to 6 m, the horizontal deformation amount of the coal wall is significantly reduced, and the stability is enhanced; The influence of anchor rod support on vertical stress is extremely small, but it can control the range of plastic zone within about 2 m in front of the coal wall. The maximum horizontal deformation is reduced by 239 mm, effectively reducing the risk of wall caving. After on-site application, the frequency of wall caving is reduced by over 50%, achieving the effect of effectively reducing the wall caving risk.

     

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