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充分认识岩石力学参数的随机性和合理评估其概率分布特征是客观评价岩石工程稳定性的基础。以白鹤滩大型水电站的斜斑玄武岩和杏仁玄武岩为研究对象,对各约50个试样进行单轴压缩试验获得大量全应力-应变曲线。采用统计分析和假设检验的方法,研究了两种玄武岩的特征强度、变形参数、特征应变和破裂面角度的随机分布特征和最优的概率密度函数形式。分析结果揭示:离散性是玄武岩的固有属性,只有一定数量的多次重复试验才能可靠地评估其基本力学特性;两种玄武岩的特征强度、变形参数、特征应变和破裂面角度的最优概率分布形式并不一致,分别为正态分布、对数正态分布、Weibull分布和Weibull分布。该试验的统计分析结果可为深入认识火成岩的变形破坏规律和工程安全可靠度或失效概率研究提供试验数据支撑。
Fully understanding the randomness of rock mechanics parameters and reasonably evaluating their probability distributions are the basis for objectively evaluating the stability of rock engineering. Taking Baihetan Hydropower Station as a research object, we studied the shear stress basalt and almond basalt on a large scale hydropower station. A total of 50 stress-strain curves were obtained by uniaxial compression tests on about 50 specimens. By means of statistical analysis and hypothesis testing, the characteristics of two kinds of basalt, the characteristics of deformation parameters, the distribution characteristics of characteristic strain and rupture angle and the optimal form of probability density function are studied. The analysis results reveal that discreteness is an inherent property of basalt, and only a certain number of repeated tests can reliably evaluate its basic mechanical properties. The optimal probability distributions of characteristic strength, deformation parameter, characteristic strain and rupture angle of the two basalts The forms are not consistent, respectively, normal distribution, lognormal distribution, Weibull distribution and Weibull distribution. The results of statistical analysis of this experiment can provide experimental data support for the further understanding of the law of deformation and failure of igneous rocks and the study on the reliability of engineering safety or failure probability.