三轴压缩加载频率对花岗岩疲劳特性影响试验

    Effect of loading frequency on fatigue characteristics of granite under tri-axial compression

    • 摘要: 通过选取岩性均一性好的北山花岗岩,并采用MTS 815岩石力学试验机对其进行三轴条件下的动态疲劳压缩试验,以探讨加载频率对岩石变形特性和损伤演化的影响。通过试验分析,得出花岗岩疲劳变形过程均可分为“疏-密-疏”三个阶段,与岩性和试验条件无关,且其损伤过程同样主要受侧向膨胀的主导作用。此外,频率的变化不会改变岩样破坏时的极限变形量,可采用弹性模量、塑性体积应变,以及横向应变等方法对岩石疲劳损伤过程进行合理描述;同时还揭示了频率变化对岩样疲劳寿命的影响规律。

       

      Abstract: The dynamic fatigue compression test under the tri-axial condition is carried out by using the MTS815 rock mechanics test system to Beishan granite with good lithology uniformity to investigate the influence of loading frequency on rock deformation characteristics and damage evolution.Through the experimental analysis, it is concluded that the fatigue deformation process of granite can be divided into three stages “sparse-density-sparse”, which has nothing to do with lithology and test conditions; and its damage process is also mainly dominated by lateral expansion.In addition, the change of frequency does not change the ultimate deformation of rock sample failure.The fatigue damage process of rock sample can be reasoned by plastic volumetric strain method and elastic modulus method.The influence of the frequency for fatigue life of rock sample is also revealed.

       

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