某金矿矿岩尺寸效应性质试验研究及应用

Experimental Study and Application of Size Effect Properties of Ore Rock in a Gold Mine

为指导某金矿留设安全矿柱,采用理论分析和室内试验的方法深入研究了矿岩尺寸效应规律。对不同高径比和不同体积(高径比相同)的矿岩试件进行了单轴压缩试验,分析了岩石单轴抗压强度、裂纹分形维数及声发射信号与岩石试件尺寸间的关系。试验结果表明:随试件体积增加,矿岩单轴抗压强度呈减小的趋势,下降规律与Weibull分布统计模型吻合度较高;采用图像二值化方法得到了破坏后试件表面裂纹分形维数与强度关系;声发射事件数与试件高径比和放大系数呈明显的线性关系,大试件声发射信号表现为强度高、分布分散的特点,小试件声发射信号强度小而分布集中。基于上述研究结果,改进了矿柱强度经验公式,改进后公式更加全面地考虑了矿柱形状效应和体积效应,并引入了破坏概率,更符合现场情况。

In order to guide the establishment of safe pillars in a gold mine,the law of ore-rock size effect was studied in depth by means of theoretical analysis and laboratory tests.Uniaxial compression tests were carried out on rock specimens with different height-diameter ratios and different volumes(the same height-diameter ratio),and the relationship between rock uniaxial compressive strength,crack fractal dimension,acoustic emission signal and rock specimen size was analyzed.relation.The test results show that with the increase of the specimen volume,the uniaxial compressive strength of ore rock tends to decrease,and the decreasing law is in good agreement with the Weibull distribution statistical model.The relationship between dimension and intensity;the number of acoustic emission events has an obvious linear relationship with the height-diameter ratio and amplification factor of the specimen.The acoustic emission signal of the large specimen has the characteristics of high intensity and dispersed distribution,and the acoustic emission signal of the small specimen is small and The distribution is concentrated;based on the above research results,the empirical formula of pillar strength is improved.The improved formula more comprehensively considers the effect of pillar shape and volume,and introduces the probability of failure,which is more in line with the field conditions.