浅埋房式采空区煤柱群稳定性评价

Stability evaluation on pillar system of room and pillar mining in goaf at shallow depth seam

基于"品"字形煤柱分布及尺寸、采空区上方塑性区域边界拱角大小计算得出房式煤柱上覆平均载荷σ_(aps),结合煤柱完全塑性失稳后其邻近煤柱上覆平均载荷变化规律定义了煤柱单元失稳概率P_0。采用重整化群方法将煤柱群划分并建立为一维、二维元胞模型,将煤柱失稳概率密度函数(PDF)表示为威布尔函数分布形式并给出不动点方程,进一步求解煤柱失稳临界概率。以石圪台煤矿为实例,计算3-1-1号煤层房式采空区中煤柱稳定性,结合房式采空区煤柱群数值模拟结果,评价了石圪台煤矿房式采空区煤柱群稳定性,最后选取两个房式采空区工作面进行表土层剥离揭露实验,验证煤柱群稳定性理论计算可靠性,为相邻采区及井田内房式采空区下开采提供理论及工程参照。

Based on the distribution and size of the pillars which resembled as Chinese character ＂品＂and the size of the arch in the plastic zone boundary above the goaf,the average overlying load of pillar under steady state is calculated. Combined with the average overlying load change law of the adjacent pillar after the fully plastic instability of pillar,the unit instability probability of pillar is defined. The renormalization group method is used to divide pillar system,and one dimensional and two dimensional cellular models are established. The probability density function（ PDF）of the pillar instability is expressed as the distribution of Weibull function and its fixed point equation is solved,then the reasonable solution are selected as the critical probabilities of pillar instability. Based on the geologic data of Shigetai Mine,the FLAC3 D numerical simulation model is established to analyze the cellular model and the instability probability distribution of pillar system,and the stability of pillar system in the room and pillar mining goaf of Shigetai Mine is evaluated.