榆神府矿区双煤层开采覆岩破坏及地面沉降特征研究

    Research on overburden failure and land subsidence characteristics of double coal seam mining in Yushenfu Mining Area

    • 摘要: 为研究双煤层开采条件下浅埋煤层覆岩破坏特征及地表沉降规律,以榆神府矿区典型浅埋煤层地质条件为基础,采用数值模拟方法,分析了6种不同工况下双煤层开采时覆岩破坏与地表沉降特征,并用物理相似模拟实验加以验证。结果表明:浅埋煤层覆岩破坏方式为全厚切落,留煤柱开采时隔水层中采动破坏呈现“泥盖效应”,不留煤柱开采时采空区两侧形成离层裂隙发育区,裂隙沿采空区两侧上方呈约45°发展;煤层开采时地表呈台阶式下沉,随着工作面推进,地表沉降中心不断前移,隔水层重量对地面沉降的影响逐渐减小,煤层厚度与地表沉降值呈正相关性;煤层开采过程中存在应力集中现象,上覆岩层中垂直应力沿煤层开采方向依次出现应力集中区、应力卸压区和应力集中区。

       

      Abstract: In order to study the overburden failure characteristics and surface subsidence law of shallow buried coal seam under the condition of double coal seam mining, based on the geological conditions of typical shallow buried coal seam in Yushenfu Mining Area, the numerical simulation method was used to analyze the overburden failure and surface subsidence characteristics under six different working conditions, and the physical similarity simulation experiment was used to verify. The results show that the failure mode of shallow buried coal seam is full-thickness cutting, and the mining-induced failure in the water-resisting layer in the retained coal pillar mining presents the “mud cover effect”. When the coal pillar is not retained, the two sides of the goaf form the development zone of separated cracks, and the cracks develop about 45° above the two sides of the goaf. The surface subsidence is stepped when the coal seam is mined. With the advance of the working face, the surface subsidence center moves forward continuously, and the influence of the weight of the aquifer on the surface subsidence is gradually reduced. The thickness of the coal seam is positively correlated with the surface subsidence value. There is stress concentration in the process of coal seam mining. The vertical stress in the overlying strata appears stress concentration area, stress relief area and stress concentrationarea successively along the direction of coal seam mining.

       

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