浅埋大采高工作面超前支承压力峰值演化规律

Evolution law of the peak of front abutment pressure of large mining height working face in shallow buried

采场支承压力分布规律与峰值位置,对采场巷道超前支护和来压监测预报等都具有重要价值。以张家峁煤矿浅埋薄基岩大采高22201工作面为背景,基于现场实测,采用UDEC数值计算、物理相似模拟、理论分析相结合的方法,对浅埋大采高工作面超前支承压力峰值演化规律进行了研究。结果表明:在埋深95 m,采高3~7 m条件下,工作面超前支承压力峰值随采高的增大而减小,峰值位置向煤壁深处转移。初采阶段,随着采高增大支承压力峰值下降了5%,峰值距煤壁距离增大了92%,但与采高之比下降18%。充分采动后,随采高增大支承压力峰值下降了14%,峰值位置距煤壁距离上升14%,支承压力峰值和峰值距煤壁距离都大于初采阶段。通过工作面煤岩体极限平衡理论分析,给出了支承压力峰值位置计算公式,超前支承压力峰值位置与采高呈近似线性关系,理论计算与实验和实测吻合。

The distribution law and peak position of stope abutment pressure have important application value for production practices such as advancing support of stope roadway and weighting forecasts.Taking the 22201 working face with the large mining height in shallow buried thin bedrock of Zhangjiamao Coal Mine as a background,a study has been made of the evolution law the peak front abutment pressure based on field measurement combined methods including UDEC numerical calculation,physical simulation and theoretical analysis.The results show that the peak of front abutment pressure decreases with increasing of mining height,and peak pressure position shifts to the depth of the working face,under conditions of buried depth 95 m and mining height 3~7 m.At the initial mining stage,as the mining height increases,the peak of abutment is pressured decrease by 5%,the distance between peak position and coal wall are increased by 92%,but the ratio of peak to mining height is decreased by 18%.After critical mining,the peak abutment pressure decreases by 14%as the mining height increases,and the distance from the peak position and the coal wall increases by 14%.The distance between peak pressure and coal wall is greater than that at the initial mining stage.The peak pressure and the distance between the peak and the coal wall are both greater than that at the initial mining stage as mining height increases.Based on theoretical analysis of limit equilibrium of coal and rock mass in working face,calculation formula for peak of frout abutment pressure was given in an linear relationship with the mining height,and theoretical calculations agree with experimental and measured results.