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针对砂岩岩样,探讨围压作用时不同频率轴向循环荷载下的疲劳损伤特性,研究频率对砂岩岩样的疲劳力学性质的影响。采用的试验设备是MTS–815岩石和混凝土试验系统,试验围压分别为2,10和40 MPa,施加的循环荷载频率分别为0.1,1.0,3.0 Hz。岩样为汶川地区的干砂岩,试样平均直径为48.9 mm,高度与直径之比为2∶1。试验结果表明:(1)在相同围压作用下,频率对岩样的残余变形、疲劳刚度和破坏模式有很大影响,频率越高,破坏时的残余轴向应变越大,破坏次数越多,岩样的初始刚度越大;(2)提出的疲劳损伤变量D可以描述岩样在循环荷载作用下的疲劳损伤过程。
In view of the sandstone samples, the fatigue damage characteristics under different axial cyclic loading under confining pressure and the influence of frequency on the fatigue properties of sandstone samples were investigated. The test equipment used was a MTS-815 rock and concrete test system with a test confining pressure of 2, 10 and 40 MPa respectively and a cyclic loading frequency of 0.1, 1.0 and 3.0 Hz respectively. The rock sample is a dry sandstone in Wenchuan area with an average sample diameter of 48.9 mm and a height to diameter ratio of 2: 1. The results show that: (1) At the same confining pressure, the frequency has a great influence on the residual deformation, fatigue stiffness and failure mode of the rock specimen. The higher the frequency, the greater the residual axial strain at failure and the more the failure times (2) The proposed fatigue damage variable D can describe the fatigue damage of rock specimens under cyclic loading.