近距离煤层采空区下沿空留巷围岩变形控制技术

Deformation Control Technology for Surrounding Rock of Retaining Roadway Along Goaf under Close Distance Coal Seam Goaf

  • 摘要: 针对山西中阳荣欣焦化有限公司高家庄煤矿4101轨道顺槽作为近距离煤层(4号煤与3号煤平均间距3.0 m)采空区下沿空留巷时,传统钢管混凝土墩柱空间占用率高、顶升可缩式支柱易密封失效的问题,通过力学分析构建顶板结构模型,提出薄壁约束混凝土墩柱巷旁支护技术方案,其壁厚较传统支护方案降低30%以上,利用混凝土与薄壁协同实现“高阻-大变形”特性,且配套高预应力锚索补强、超前/滞后加强支护等措施,地面原位试验表明直径800 mm的墩柱抗压强度达10 000 kN以上,同等承载力下单根墩柱占用巷道净宽从0.8 m减至0.7 m,空间利用率提升12.5%。现场工业性试验结合超声地质雷达探测结果显示,留巷稳定段顶板裂隙场发育范围为0~2.45 m,实体煤帮裂隙场发育范围为0~2.85 m,均在锚杆/索控制范围内。顶板最大沉降约为203 mm,底板抬升幅度小于50 mm,相较于传统方案有显著改善,围岩变形控制在合理区间内,进一步验证了该方案的适应性。

     

    Abstract: Aiming at the problems of high space occupation rate of traditional steel tube concrete pier column and easy sealing failure of jack up retractable pillar when the 4101 track crossheading as the retaining roadway along goaf under the close distance coal seam goaf (with an average distance of 3.0 m between No. 4 coal and No. 3 coal) of Gaojiazhuang Coal Mine of Shanxi Zhongyang Rongxin Coking Co., Ltd., a roof structure model is constructed through mechanical analysis, and a roadway side support technology scheme for thin-wall constrained concrete pier column is proposed, the wall thickness is reduced by over 30% compared to the traditional support scheme, and the "high resistance-large deformation" characteristic is achieved by utilizing the coordination of concrete and thin-wall. In addition, supporting measures such as high pre-stressed anchor cable reinforcement, advanced/lagged strengthening support and others are taken. The ground in-situ tests show that the compressive strength of pier columns with a diameter of 800 mm reaches over 10 000 kN, under the same bearing capacity, the net width occupied by a single pier column in the roadway is reduced from 0.8 m to 0.7 m, and the space utilization rate is improved by 12.5%. The on-site industrial test combined with ultrasonic geological radar detection results indicate that the development range of the roof fissure field in the stable section of the retaining roadway is 0-2.45 m, and the development range of the solid coal side fissure field is 0-2.85 m, both within the control range of anchor rod/cable. The maximum subsidence of the roof is about 203 mm, and the floor uplift amplitude is less than 50 mm, which is significantly improved compared to the traditional scheme. The surrounding rock deformation is controlled within a reasonable range, which further verifies the adaptability of this scheme.

     

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