北山花岗岩在三轴压缩条件下的强度参数演化

发布时间：2018-04-10 19:03

本文选题：岩石力学 + 北山花岗岩　；参考：《岩石力学与工程学报》2017年07期

【摘要】：采用MTS815岩石力学试验机对北山新场深部花岗岩进行三轴循环加、卸载试验,研究岩石强度参数的演化特征。基于Mohr-Coulomb相关理论推导与分析,探讨岩石发生屈服后的强度变化规律。在分析不同围压条件下岩石全应力应变曲线的基础上,以塑性剪切应变为塑性参数,建立北山花岗岩黏聚力、内摩擦角和剪胀角随塑性参数变化的数学模型。研究结果表明:(1)在损伤应力点,岩石塑性剪切应变接近于0,损伤应力可作为北山花岗岩塑性参数的零点,其亦可作为岩石强度参数演化的起点。(2)在损伤应力点后,岩石黏聚力随塑性参数的增加呈指数函数形式衰减并最终趋近于0;内摩擦角随塑性参数的增加以对数正态函数的形式表现出先增加后减小的趋势,且岩石残余内摩擦角值与起始内摩擦角值接近。(3)损伤应力后的岩石剪胀行为与峰后剪胀行为相似,剪胀角随着塑性参数和围压的增加而不断减小,且对低围压条件更为敏感。(4)将建立的模型嵌入到数值模拟工具中,通过模拟岩石三轴压缩试验,可证实模型的准确合理性。
[Abstract]:Based on the derivation and analysis of Mohr-Coulomb theory, the change law of rock strength after yielding is discussed.Based on the analysis of the total stress and strain curves of rocks under different confining pressures, a mathematical model of the cohesion, internal friction angle and shear expansion angle of Beishan granite with plastic parameters is established with plastic shear strain as a plastic parameter.The results show that at the damage stress point, the plastic shear strain of the rock is close to zero, and the damage stress can be used as the zero point of the plastic parameter of the Beishan granite, and it can also be used as the starting point of the evolution of the rock strength parameter.The cohesion of rock decreases as exponential function with the increase of plastic parameters, and the angle of internal friction increases first and then decreases with the increase of plastic parameters.And the residual internal friction angle of rock is close to that of initial internal friction angle.) the dilatancy behavior of rock after damage stress is similar to that of post-peak shear expansion behavior, and the shear expansion angle decreases with the increase of plastic parameters and confining pressure.
【作者单位】：核工业北京地质研究院;
【基金】：国家自然科学基金资助项目(11102061)~~
【分类号】：TU45

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