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采用散体充填法的矿山,由于充填体无法直接暴露,阶段矿柱回采临界厚度的保留成为残矿回收的突出难题。基于传统弹性梁理论,结合实际情况,将阶段矿柱简化为均布载荷下两端固定的弹性梁力学模型,推导了其弹性应力解,揭示了x?是阶段矿柱上采过程的第1破坏应力。理论分析表明:影响矿柱上采顶板临界厚度的主要因素为:散体载荷、回采跨度和岩体抗拉强度。利用FLAC3D完成了多因素组合影响阶段矿柱上采过程数值模拟正交试验,分析了单一影响因素与顶板临界厚度的关系,利用多元非线性回归的数学方法,建立了上采过程三因素组合影响下阶段矿柱临界厚度数学预测公式。最终,实现了散体介质下阶段矿柱上采临界厚度的预测。结合凤凰山铜矿-240 m阶段矿柱回采实际,表明了该预测公式的适用性。
Due to the inability of the filling body to be directly exposed, the retention of the critical thickness of the ore pillar in the stage has become a prominent problem in the recovery of residual ore. Based on the traditional elastic beam theory, combining with the actual situation, the pillars of the stage are simplified as the mechanical model of elastic beam fixed at both ends under uniform load, and the elastic stress solution is derived. It is revealed that x? Is the first Disrupt the stress. The theoretical analysis shows that the main factors that affect the critical thickness of upper roof mining pillar are: bulk load, recovery span and rock mass tensile strength. FLAC3D is used to complete the orthogonal experiment of numerical simulation of upper mining process with multi-factors combined influence stage. The relationship between single influencing factors and the critical thickness of roof is analyzed. The mathematical method of multiple nonlinear regression is used to establish the influence of three factors Mathematical Prediction Formula of Pillar Critical Thickness in Lower Stage. Finally, the predicting of the critical thickness of upper mining pillars in bulk media is achieved. According to the fact that the pillar recovery at -240 m in Fenghuangshan Copper Mine is practical, the applicability of this prediction formula is demonstrated.