云驾岭煤矿采动覆岩裂隙场分布特征模拟研究

    Simulation on distribution characteristics of mining-induced fractures field in overburden of Yunjialing Coal Mine

    • 摘要: 为了研究云驾岭煤矿采动覆岩裂隙场分布及其演化规律,通过相似模拟试验和UDEC数值模拟方法探究了采动后上覆岩层的下沉曲线与裂隙场分布特征,计算覆岩离层率空间分布情况。结果表明:随着开挖工作的不断推进,采动覆岩裂隙场呈梯形分布特征,逐步向较高层位和推进方向发育,其中下部裂隙被压实,两端裂隙较为发育,整体上裂隙密度逐步减小,经历裂隙产生、扩展和压实三个阶段,而覆岩离层率先后经历“单峰”和“双峰”两个分布形态。采空区中部与煤壁后方和开切眼附近区域采动裂隙演化规律截然不同,采空区中部区域的采动裂隙随着垮落岩层被上覆岩层压实,采动裂隙逐渐减小,煤壁后方和开切眼附近区域,边界煤柱和垮落岩层形成三角形的采动裂隙区域。采动覆岩位移场影响区随着工作面推进向高层位和推进方向发育,开采初期呈现矩形分布,而后随工作面的推进,采动覆岩位移场影响区则呈现梯形分布,中部的位移矢量箭头垂直于底板,开切眼和工作面端位移矢量分别呈逆时针和顺时针偏转。

       

      Abstract: In order to study the distribution and evolution law of mining-induced fractures field in overburden of Yunjialing Coal Mine, the subsidence curve and fracture field distribution characteristics of overlying strata after mining are explored by physical simulation and UDEC numerical simulation methods, and the spatial distribution of fracture rate of overlying strata is calculated. The paper concludes that with the continuous progress of excavation, the mining-induced fractures field is characterized by trapezoidal distribution, and gradually develops toward higher layers and advancing direction. The lower fractures are compacted, and the fractures at both sides are relatively developed. The overall fracture density is gradually reduced, going through three stages of fracture generation, expansion and compaction. The fracture rate has experienced two distribution patterns, namely, “single peak” and “double peak”. The evolution law of mining-induced fractures in the middle of the goaf is quite different from that in the area behind the coal wall and near the open-off cut. The mining-induced fractures in the middle of the goaf gradually decrease with the compaction of the caving rock layer by the overlying rock layer. In the area behind the coal wall and near the open-off cut, the boundary coal pillar and the caving rock layer form a triangular mining-induced fracture area. The affected area of mining overburden displacement field develops towards the high layer and the advancing direction with the advance of the working face. At the initial stage of mining, it presents a rectangular distribution. Then, with the advance of the working face, the affected area of mining overburden displacement field presents a trapezoidal distribution. The displacement vector arrow in the middle is perpendicular to the floor, and the displacement vector at the open cut and the working face end deflects counterclockwise and clockwise respectively.

       

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