综放工作面上覆岩层变形破坏时空演化特征试验研究

采用相似模拟实验方法进行采空区工作面顶板垮落过程中上覆岩层变形破坏试验研究。以CCD相机构建实验图像数据采集系统,采用数字散斑相关方法对上覆岩层位移场和垮落角进行了分析,研究了上覆岩层垮落区域裂隙演化、位移演化及偏态特征。研究结果表明:工作面顶板垮落过程中上覆岩层垮落角角度随垮落区域形状不断变化,垮落高度逐渐减小直至平稳,垮落面积逐渐增大直至平稳;在竖直方向上,上覆岩层垮落带呈宽缓的W型沉降、裂隙带和弯曲下沉带呈V型沉降;在水平方向上,下部上覆岩层向两侧移动、上部岩层向中间移动,造成各岩层间发生摩擦滑动,并对两侧未开挖区域及煤柱产生弯矩作用;工作面顶板跨落后形成偏态,开切眼侧垮落角大于开采侧垮落角,并在开采侧形成岩移角,开切眼侧的下沉曲线较陡、工作面侧下沉曲线较缓。根据实际工程背景,计算了地表塌陷影响范围,为煤矿开采对上覆岩层影响范围和程度以及后续采空区治理等问题评估提供了必要依据。

Experimental study on the characteristics of spatiotemporal evolution of overburden deformation and failure in fully mechanized caving face

Using a similar simulation experiment method, the deformation and failure test of the overlying strata during the roof collapse of the working face in the goaf was carried out. A CCD camera was used to construct the experimental image data collection system, and the digital speckle correlation method was used to study the crack evolution, displacement evolution and skew characteristics of the overburden collapse zone. The research results show that: (1) During the roof collapse of the working face, the angle of the overburden strata angle changes continuously with the shape of the collapsed area, the height of the collapse gradually decreases until it becomes stable, and the area of the collapse gradually increases until it becomes stable. (2) During the collapse of the overburden layer, in the vertical direction, the collapse zone of the overburden layer exhibits a wide "W" type settlement, and the fissure zone and the curved subsidence zone exhibit a "V" type settlement; in the horizontal direction The upper and lower overburden strata move to both sides, and the upper strata move to the middle, which will cause frictional sliding between the rock layers and produce bending moments on the unexcavated areas and coal pillars on both sides. (3) The roof of the working face is skewed after lagging behind. The fall angle on the side of the cut is greater than that on the mining side, and a rock shift angle is formed on the mining side. The settlement curve is slow; (4) According to the actual engineering background, the overburden strata in the goaf caused by the collapse of the working face roof, resulting in the collapse angle including surface collapse of 114.4m, the actual surface impact range is 174.7m, which is coal mine Mining has provided the necessary basis for the assessment of the impact range and degree of overlying rock strata and subsequent governance of mined-out areas.