乌东矿急倾斜特厚煤层水平分段综放开采顶板破断特征研究

为研究急倾斜特厚煤层水平分段综放开采顶板破断特征,基于急倾斜特厚煤层工作面顶板赋存条件并结合弹性力学,建立了急倾斜特厚煤层水平分段开采顶板力学模型。通过力学模型分析,推导出急倾斜特厚煤层水平分段开采后顶板沿工作面倾向方向的岩板破断判据及挠度公式,应用三角级数方法对挠度公式进行求解,确定了顶板沿倾向方向上最大挠度发生的位置关系式。理论研究成果在乌东矿南采区B1+2急倾斜特厚煤层水平分段综放开采中的工程应用表明,工作面沿倾向方向上推进到385 m时顶板发生破断,倾向方向顶板最大挠度坐标位置为y=325.78 m,顶板沿工作面倾向方向的最大挠度位于采空区中部偏下位置。表现为急倾斜特厚煤层顶板在工作面上方的非对称性破断;相似材料试验进一步验证了顶板挠度公式的合理性。

Investigation of the roof-destructive features of the steep-declining extra-thick seam for the horizontal section extraction in Wudong Mine

The paper is aimed at investigating the roof-destructive features of the steep-declining extra-thick seam for the horizontal section extraction in Wudong Mine.For the said purpose,we have established a roof deformation mechanical model for exploring the coal seam roof breaking mechanism and behavior of its working face according to the roof deformation elastic plate kinetics theory.At the same time,we have also gained the roof failure criterion formula and the deflection formula in the direction of the working face through analyzing the mechanical model.Furthermore,we have also delimited and determined the boundary conditions of the dynamic model according to the actual state of roof in such extra-thick coal seam.In addition,we have also deduced the deflection formula with the trigonometric series method and the maximum deflection position in the dip said direction of the working face via Taylor's expansion.Besides,the theoretical achievements have also been applied to the examination of such coal seam in Wudong South Panel B1 + 2,showing that the roof tends to get spoilt in the inclined direction of the working face on the condition when the working face moves to 385 m and the maximum deflection position tends to be y =325 m in the said direction.Therefore,the maximum deflection position should be located at the lower part of the goaf,suggesting that the roof breaking has no longer been symmetrical in the above mentioned extrathick coal seam with the top-coal caving of the horizontal section.Thus,what we have found above has further verified the rationality of the mechanical model of the roof deformation and the scientific nature of the formula of the roof deflection via the experiment results and the similar material simulations.Thus,the above research results are expected to provide a significant reference for exploring the regularity of mine pressure,the roof control of the working face and the design of roadway support in such extrathick coal seams with horizontal section top-coal caving.