云冈煤矿充填开采设计与顶板覆岩变形破坏时空演化规律研究

    Study on filling mining design and spatial-temporal evolution law of deformation and failure of roof overburden in Yungang Coal Mine

    • 摘要: 以云冈煤矿8402工作面充填开采为背景,首先制备了5种不同配比的矸石浆,开展了泌水率、凝结时间和单轴抗压强度测试,根据使用要求和成本要求选择了合理的矸石浆配比,并进行了充填液压支架与充填开采工艺设计;考虑岩体力学参数随开采应力的变化,基于Hoek-Brown模型,采用FLAC3D软件研究分析了有无充填2种条件下8402工作面顶板覆岩的变形破坏时空演化规律。研究结果表明:水泥和粉煤灰用量分别为180 kg/m3和210 kg/m3时,可同时满足云冈煤矿8402工作面充填开采使用和成本要求;无充填条件下8402工作面周期来压步距约18~25 m,裂隙带发育高度约108 m;而85%膏体充填条件下工作面周期来压步距约36~40 m,裂隙带发育高度则约43 m;85%膏体充填下工作面向前推进120 m后,其地表最大沉降和最大倾斜基本保持为165 mm和2.62 mm/m不变,小于规范的规定要求,能够确保地面建筑的安全。

       

      Abstract: Taking the filling mining in Yungang Coal Mine 8402 working face as the background, firstly, five gangue slurry with different proportions were prepared, and bleeding rate, setting time and uniaxial compressive strength tests were tested. Reasonable gangue slurry ratios were selected according to the requirements of use and cost, and the design of filling hydraulic support and filling mining technology was carried out. Considering the change of rock mass mechanical parameters with mining stress, based on Hoek-Brown model, FLAC3D software was used to study and analyze the spatial-temporal evolution law of deformation and failure of roof overburden in 8402 working face with or without filling. The results show that: when the dosage of cement and fly ash is 180 kg/m3 and 210 kg/m3 respectively, it can meet the requirements of filling mining and cost of 8402 working face in Yungang Coal Mine at the same time; under the condition of no filling, the 8402 working face has a periodical pressure step of 18-25 m, and the height of fracture zone is 108 m. While under the condition of 85% paste filling, the periodical pressure step of the working face is 36-40 m, and the height of fracture zone is 43 m; after the working face with 85% paste filling advances 120 m, the maximum subsidence and maximum tilt of the surface are basically kept unchanged at 165 mm and 2.62 mm/m, which are less than the requirements of the code and can ensure the safety of the ground building.

       

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