极破碎中厚矿体开采方法及稳定性分析

根据极破碎中厚矿体开采中下向进路承载层受力特点, 将其简化为受均布载荷及自重应力的简支“梁”模型, 求出承载层最大拉应力σ_tmax的表达式, 并以最大拉应力强度理论作为承载层的破坏判据, 由此得出下向进路不同承载层厚度与安全系数的关系曲线。当进度高度为3.4 m, 进路宽度为3.0 m时, 安全系数法分析表明人工假顶厚度1.4 m为最优。利用二维有限元分析矿山原有的1.0 m厚人工假顶与安全系数法得出的1.4 m厚人工假顶进路的稳定性, 结果表明下向进路回采时, 影响进路稳定性的主要因素是充填体的力学特性, 顶板沉降位移统计表明, 采用1.4 m厚人工假顶的进路顶板稳定, 与安全系数法分析结果一致。

Mining Method for Extremely Fractured Medium-thick Orebody and Corresponding Stability Analysis

According to stress characteristics of loading layer in downward advancement of extremely fractured medium-thick orebody, the expression of its maximum tensile stress (σ_tmax) was obtained after simplifying supported beam model under uniform load and gravity stress. The maximum tensile stress theory was taken as failure criterion for loading layer, thus the relation curve between different thickness of loading layer and safety coefficient could be drawn. Analysis with safety coefficient method showed that the artificial roof was optimally 1.4 m in thickness, when the drift was 3.4 m high and 3.0 m wide. Two-dimensional finite element method was used to analyze the stability of drift with existing artificial roof with 1.0-meter thickness or 1.4-meter thickness obtained with safety coefficient method. Results showed that, what affects the stability mainly was mechanical property of backfills during downward advancement. Statistical analysis of roof displacement caused by settlement shows that the drift is stable with artificial roof of 1.4 meters thick, which is in agreement with the analysis result by safety coefficient method.