Layout of roadway under goaf based on scale effect of mining cross upper coal pillar
LYU Kai;HE Fulian;XU Xuhui;WANG Fuzhong;QIN Binbin;LI Liang
针对遗留煤柱对下位巷道及采场产生的不利影响,以近距离煤层下行开采为背景,采用理论解析及现场实测等方法,对煤柱下底板偏应力不变量的区域特征、工作面出煤柱压架灾害的发生机理及其尺度效应展开研究。结果表明:(1)当上煤层相邻工作面开切眼位置不平齐时,下位巷道通过采取平错式布置,在保障巷道自身稳定的前提下,成功将工作面全长出一侧采空煤柱转化为2次小范围的出煤柱过程,实现对采场压架灾害的提前防治。(2)采用偏应力第二不变量(J2)、偏应力第三不变量(J3)和偏应力第二不变量(J2)水平变化率解析煤柱下方底板岩层的应力状态,并对底板进行分区,确定下位巷道平错距离的下限值为24 m。(3)工作面出煤柱期间,初次来压或周期来压与顶板-煤柱系统突变失稳产生的动载矿压耦合叠加形成冲击是压架灾害发生的根本原因,计算出煤柱尺度效应,得到平错距离上限值为36 m。燕子山煤矿工业性实践验证了下位巷道采取平错式布置且平错距离为30 m的可行性与合理性。
With the condition of contugous double-thick coal seams downward mining as the background, in view of the adverse effects ofupper remaining coal pillars on the stability of mining roadway and stope, the field measurement and theoretical analysis are adopted tostudy the regional characteristics of the deviatoric stress invariant under section coal pillar, the mechanism of strong strata behaviors duringmining cross the upper boundary coal pillar and its scale effect. The research shows that: ① When the position of open-off cuts is noteven in the upper seam, a transverse translation layout is adopted for the lower mining roadway, which not only place the roadway in astable stress environment, but also prevent the collapse disaster by transform the whole mining cross the upper coal pillar into twice smallrangeprocesses. ② The stress state of floor rock under section coal pillar is analyzed with the second deviatoric stress invariant (J2) intensity,the third deviatoric stress invariant (J3) intensity,and the second deviatoric stress invariant (J2) horizontal gradient. The floor is partitionedby the three indexes, and the minimum horizontal distance between roadway and section coal pillar is determined to be 24 m.③ During the mining cross the upper coal pillar, the combined interaction of the first or periodical weighting and the sudden instability ofroof and coal pillar system is the basic reasons for the strong strata behaviors. Based on the scale effect of mining cross the upper coal pillar,the maximum horizontal distance between mining roadway and section coal pillar is determined to be 36 m. The feasibility and rationality of the transverse translation layout of 30 m in lower mining roadway was verified by the field measurement of typical coal mine.
contugous coal seam; remaining coal pillar; transverse translation layout; the deviatoric stress invariant; mining cross the upper coal pillar; roof and coal pillar system
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