Space time evolution characteristics of stress transfer path of surrounding rock in longwall mining of steeply dipping seam
LUO Shenghu,WANG Tong,WU Yongping,TIAN Chengyang,LANG Ding, ZHAO Huatao
西安科技大学理学院,陕西 西安西安科技大学 西部矿井开采及灾害防治教育部实验室,陕西 西安西安科技大学 能源学院,陕西 西安山东矿机集团股份有限公司
大倾角煤层开采中,受煤层倾角影响,采动应力在顶板岩层中的动态演化规律较一般煤层 开采时复杂,发现并揭示采动应力的传递路径与宏观展布形态的演化特征是实现该类煤层安全高 效开采的基石。 以某矿 25221 工作面为工程背景,采用模拟实验、数值模拟、理论分析互馈的研究 手段,在厘定围岩宏观结构演化规律的基础上,量化了围岩空间主应力包络面空间展布形态,揭示 了围岩采动应力传递路径时空演化特征。 研究结果表明:在大倾角煤层开采中,围岩破坏拱壳形态 在高度上呈现先增大后趋于稳定的特征,倾向上、下端头位置处,壳基随着推进距离的增大而向深 处煤体内偏移后趋于稳定;围岩应力包络拱壳呈现壳顶在工作面倾向中上部、壳基在采场四周煤体 内的非对称拱壳体形态;围岩支承压力峰值的演化分为峰值增长区与稳定区;主应力受采动影响在 煤壁前方呈现出先增大后减小的变化规律,而在采空区中部 3 者均下降且第一主应力下降幅度最 大;第一主应力受采动影响,其应力传递路径可分为原岩应力区、应力增高区、应力降低区 3 个区 域;应力增高区内,第一主应力在 Z 轴分量增加幅度最大,其方向自垂直于 Y 轴平面内旋转。 研究 结果揭示了顶板宏观应力拱壳与应力传递路径演化一般规律,丰富了大倾角煤层岩层控制理论。
The spatial distribution pattern and the transmission path of mining stress in the roof of a steeply dipping seam are more complicated than that in a horizontal coal seam affected by the angle of the coal seam during the mining process of steeply dipping coal seams. Discovering and revealing the macroscopic distribution of mining stress and the evolution characteristics of the stress transfer path are the cornerstones for the safe and efficient mining of this type of coal. Taking 25221 working face of a mine as engineering background,this paper adopted the comprehensive research methods of simulation experiment,numerical simulation,and theoretical analysis. On the basis of determining the macroscopic structural evolution law of the surrounding rock of the coal seam,the spatial distribution of the principal stress enveloped arch shell in the surrounding rock space was quantified,and the spacetime evolution characteristics of the mining stress transfer path of surrounding rock were revealed. The results show that the shape of surrounding rock failure archshell increases first and then tends to be stable in height during the mining process of the steeply dipping seam. With the increase of the advancing distance,the shell base at the headgate Tjunction and tailgate Tjunction of working face shifts to the deep coal pillar and then tends to be stable. The surrounding rock stress envelope arch shell presents an asymmetric arch shell with the top in the middle and upper part of the working face and the base in the coal body around the stope. The evolution of the abutment pressure peak can be divided into growth area and stable area. The principal stress first increases and then decreases in front of the coal wall under the influence of mining,while in the middle of the minedout area,the three all decrease,and the first principal stress decreases the most. The transfer path of the first principal stress affected by mining can be divided into three areas: original area,increasing area,and decreasing area. In the increasing area,the first principal stress increases most in the Zaxis component,and its direction rotates perpendicular to the Yaxis plane. The research results reveal the evolution mechanism of macroscopic stress arch shell and stress transfer path of the roof,which enriches the strata control theory of steeply dipping coal seam.
steeply dipping seam,stress arches shell,abutment pressureprincipal stress,stress transfer path
主办单位:煤炭科学研究总院有限公司 中国煤炭学会学术期刊工作委员会