深部硬岩矿山非规则岩样点载荷强度测试与应用

Point Load Strength Test and Application of Irregular Rock Samples in Deep Mine with Hard Rocks

针对深部高地应力矿山节理裂隙发育程度高、钻孔岩芯饼化现象频发,造成岩体质量降低、完整性程度差、现场钻孔取芯困难等问题,选取金川二矿610 m主斜坡道爆破后的非规则岩样进行点载荷试验,获得不同岩石的点载荷强度。试验结果表明:非规则岩样修正后的点载荷强度Is(50)服从正态分布,通过对比不同计算方法和修正方式下试验数据的标准差σ与变异系数δ,推荐闪长岩的点载荷强度宜采用等效直径(线性修正)法求解,花岗岩的点载荷强度宜采用加载间距法求解;非规则岩样的点载荷强度Is与形状系数β、加载间距D之间呈现明显的幂函数关系,以Is的相对偏差ω≤20%作为选样标准,确定闪长岩与花岗岩β、D的取值范围;确定了非规则岩样修正后点载荷强度Is(50)与抗拉强度σ_t、抗压强度σUCS之间的转化系数,可用于快速估算围岩强度,为岩体质量分级与巷道支护方案制定提供依据。

Due to the high degree of development of joints and fissures in deep high in-situ stress mines and the frequent occurrence of core disking in boreholes, resulting in the reduction of rock mass quality, poor integrity and difficulty in on-site drilling and coring, irregular rock samples from the main ramp at 610 m of Jinchuan No.2 Mine were select to conduct point load tests to obtain point load strength for different lithology. The test results are concluded as follows. Firstly, the modified point load strength I_(s(50)) of the irregular rock samples follows the normal distribution. Comparing the standard deviation σ and the coefficient of variation δ of the test data under different calculation methods and correction methods, it is suggested that the point load strength of amphibolite could calculate by the equivalent diameter(linear correction) method, and the point load strength of granite could calculate by the loading spacing method. Secondly, the point load strength I_s of irregular rock samples shows the obvious power function relationships with the shape factor β and the loading spacing D. The relative deviation(ω≤20%) of I_s was used as the sample selection criterion to determine the range of values of amphibolite and granite β and D. Thirdly, the relationship between the modified point load strength I_(s(50)) and the tensile strength σ_t, compressive strength σ_(UCS) for irregular rock samples was established, which can quickly estimate the strength of the surrounding rock and provide the important basis for rock mass quality classification and the roadway support scheme determination.