大倾角煤层安全高效开采的关键是对围岩的有效控制，而发现并揭示围岩采动应力的时空演化特征及其倾角效应是围岩稳定性控制的基础。以新疆某矿25221工作面为工程背景，采用现场实测、理论分析与数值计算相结合的研究方法，在综合厘定与分析工作面矿压显现一般规律及其成因的基础之上，研究顶板采动应力传递路径的时空演化特征及其倾角效应。结果显示：在大倾角煤层开采中，顶板采动应力随工作面推进的动态演化过程先后经历了增长期和稳定期，其对应支承压力峰值的演化呈现为先增大后趋于稳定的特征。受煤层倾角影响，顶板采动应力的三维传递演化沿走向对称、沿倾向非对称。在倾向剖面内，顶板应力的传递路径呈非对称拱形形态，且沿顶板自上而下，应力偏转位置由工作面倾向中轴线左侧逐渐向其右侧迁移，上覆岩层载荷以应力偏转界线为界，分别向倾向上、下侧煤体传递，造成倾向上侧支承压力集中系数大于下侧。在工作面走向剖面内，围岩应力的传递路径呈扁平拱形态，扁平拱两侧半拱形区域上覆岩层载荷除了向工作面走向两侧煤体传递外，亦向工作面倾向上、下侧煤体传递，而扁平拱中间直线段区域上覆岩层载荷主要向倾向上、下侧煤体传递。随着煤层倾角的增大，围岩应力传递演化的非对称特性显著增大，应力偏转界线与工作面倾向中轴线间的距离逐渐增大，二者交点的高度呈现为增-减-增的演化趋势；受此影响，工作面走向和倾向上侧支承压力集中系数亦呈现出增-减-增的演化趋势。顶板应力的非对称时空演化特征，造成采场空间不同区域顶板的力学性状与行为存在显著差异，这种差异性导致倾向不同区域支架的受载与失稳特征亦存在显著差异，且这一现象会随着煤层倾角的增大而愈发明显。

The key to safe and efficient mining of steeply dipping coal seam is an effective control of surrounding rock.Discovering and revealing the spatial time evolution characteristics of mining stress and the angle effect are the basis for the stability control of surrounding rock.Taking No.25221 working face of a mine in Xinjiang,China as engineering background,this paper adopted the comprehensive research methods of field monitoring,theoretical analysis,and numerical simulation.On the basis of comprehensively analyzing the general laws of abutment pressure and its causes,the spatial time evolution characteristics of the mining stress transmission path of roof and the angle effect were studied.The results show that during the mining of steeply dipping coal seams,the dynamic evolution process of roof stress and the abutment peak pressure has experienced a growth period and a stable period with the advancement of the working face.Affected by the angle of coal seam,the roof stress presents the characteristics of three dimensional transmission and evolution that are symmetrical along the strike and asymmetrical along the inclination.In the inclined section,the transmission path of the roof stress is an asymmetrical arch shape.From top to bottom,the stress deflection position gradually shifts from the left side to the right side of the working face.The load of overburden strata is transferred to the upper and lower coal seams with the stress deflection boundary as the boundary,which causes the concentration coefficient of the upper to be larger than that of the lower.In the strike section,the stress transfer path of the surrounding rock is a flat arch shape.The load of overburden strata in the semi arch area of the flat arch is not only transferred to the coal bodies on both sides along strike,but also to the upper and lower coal bodies along inclined direction.The load of overburden strata in the middle straight area of the flat arch is mainly transferred to the upper and lower coal bodies along inclined direction.As the angle of coal seam increases,the asymmetric characteristics of the stress transfer and evolution of surrounding rocks increase significantly.The distance between the stress deflection boundary and the central axis of the working face gradually increases,and the height of the intersection of the two shows an evolution trend of increasing decreasing increasing.Affected by this,the concentration coefficient of abutment pressure of strike and the upper along inclined direction show an evolution trend of increasing decreasing increasing.The asymmetrical spatial time evolution of the roof stress causes significant differences in the mechanical properties and behavior of the roof in different areas of the stope space.This difference leads to significant differences in the loading and instability characteristics of the supports in different areas,and this phenomenon will become more obvious with the increase of angle.

1 工程背景

2 支架工作阻力分区特征

3 采动应力传递路径及其倾角效应

   3.1 数值计算模型

   3.2 支承压力演化特征

   3.3 采动应力倾向传递路径及其倾角效应

   3.4 采动应力走向传递路径及其倾角效应

4 结论