大理岩弹性参数的围压效应与弹塑性耦合模型

Research on confining pressure effect of elastic parameters of marble and its elasto-plastic coupling model

以锦屏二级水电站T2 b和6T2 y深埋大理岩循环加、卸载试验结果为基础,对不同围压下大理岩弹性参数的演化规律进行研究,得出其弹性模量随围压和内变量的变化显著,而泊松比随围压则变化不明显。基于试验结果确定了锦屏大理岩弹性模量与围压和内变量的定量关系,建立了考虑弹性参数围压效应的大理岩弹塑性耦合模型,并在有限差分软件FLAC3D中进行了数值实现,用于模拟分析大理岩室内三轴压缩试验结果,并将模拟结果与不考虑弹性参数围压效应的计算结果进行对比,结果表明:考虑大理岩弹性参数围压效应的数值模拟与试验结果更吻合。研究方法和结果对于提高深部工程围岩(特别是具有小变形破坏特性的硬脆性围岩)变形计算的准确性具有重要的参考价值和借鉴意义。

Based on the results of cyclic loading tests of two types of deep buried marbles T2b and Tie from Jinping II hydropower station, evolution of elastic parameters of marble under different confining pressures is studied. The results show that the elastic modulus changes significantly with the development of confining pressure and internal variable; while Poisson＇s ratio does not change significantly with confining pressure. Quantitative relationship between elastic modulus, confining pressure and internal variable is proposed based on the test results; and an elasto-plastic coupling model is set up considering the effect of confining pressure and implemented in FLAC3D by using C＋＋ language. Then, the result of triaxial compression test is simulated. By comparing the simulating results with and without considering the effect of confining pressure, it is shown that there is significantly better agreement between the simulating results considering the effect of confining pressure and test data. Efforts of this paper can give an important reference to numerical accuracy for rockmass of deep engineering, especially for brittle rockmass with the characteristic of fracturing under small deformation.