煤层倾角变化对采动覆岩变形规律影响的相似模拟试验研究

为研究工作面开采后顶板变形破坏随煤层倾角变化的规律,以南桐矿区不同倾角的同一煤层开采为工程研究背景,分别选取缓倾斜、倾斜、急倾斜三种煤层倾角进行煤层开采顶板变形破坏规律的相似模拟试验。对相似模型开挖前后图像进行数字散斑相关法处理,得到相似模型煤层开采后顶板覆岩位移及平面总应变等值线云图。通过综合分析顶板位移及平面总应变可知：上覆岩层变形的破坏程度总体上是随煤层倾角的增加呈减小趋势,其下沉剧烈区域和膨胀变形破坏剧烈区域呈逐渐向工作面上山方向发展的趋势;根据顶板位移云图和平面总应变云图中的等值线极值区域特征,确定了缓倾斜、倾斜煤层开采垮落带、裂隙带高度和偏心程度等参数,并根据"压力拱"理论确定了急倾斜煤层开采裂隙带范围;随煤层倾角增大"两带"高度总体上呈减小趋势,且"两带"偏心方向呈向上山方向增加的趋势。

Similar simulation study on the influence of seam angle change on deformation law of overburden strata in coal seam mining

To get insight into the swelling and displacement law with seam dip angles change, similar simulation studies of gentle dip, dip and steep dip angles were conducted. The experiment angles and geometrical properties were chosen from a particular coal seam of various dip angles in Nantong Mining District. Digital speckle correlation method was used in the result analysis to quantitate the overburden strata deformation for the displacement and the total plane strain contour maps. Further analysis of the plane strain and displacement distribution gives the following major findings:generally the swelling and displacement condition will be relieved and the corresponding intense regions will rise to the upper boundary with the increase of seam angle; Based on the morphology in both contours, the interfaces of "Three Zones" were determined in the position of maximum value of contour, as well as height of caving zone and fractured zone and the eccentric degree in seam angle of gentle dip and dip; In the dip angle condition, stress arch-shell theory is used to determine height of fractured zone. Quantitative characteristic parameters show the distributions of caving zone and fractured zone are biased toward upper boundary while both heights exhibit a decrease trend.