周期荷载作用下黄砂岩疲劳破坏变形特性试验研究

为研究周期荷载对工程岩体长期稳定性的影响作用,利用Rockman207岩石力学试验系统对黄砂岩试件进行了单轴条件下不同上限应力和应力幅值的周期荷载疲劳试验。试验结果表明:黄砂岩的疲劳破坏受到静态应力–应变全过程曲线轴向、环向以及体积变形量的控制,在控制曲线的峰值强度或峰值强度之后,疲劳试验过程中会出现"初始破坏";黄砂岩疲劳破坏轴向和环形不可逆变形的3阶段发展规律的本质影响因素是产生的应变速率不同,黄砂岩的疲劳破坏过程是轴向和环向不可逆变形不断累积的过程;在一定条件下,黄砂岩的循环次数–上限应力曲线(N–S曲线)可以用来预测岩石的疲劳寿命。

Fatigue deformation characteristics of yellow sandstone under cyclic loading

In order to study the long-term stability of engineering rock mass under cyclic loading, various uniaxial tests are conducted on yellow sandstone under different maximum stresses and stress amplitudes using the rock mechanics test system Rockman207. The laboratory investigation results show that the fatigue failure of yellow sandstone is controlled by the axial strain, lateral strain and volumetric strain of the complete stress-strain curve. There is an initial failure in the process of fatigue tests, and the initial failure occurs at peak strength or behind peak strength of the control curve. The difference of strain rate is the essential factor of 3 stages of the axial and lateral irreversible deformation development laws, and the fatigue failure process of yellow sandstone is the accumulating process of axial and lateral irreversible deformations. The fatigue life of yellow sandstone can be predicted by using the cycles-maximum stress curve (N-S curve) under certain conditions.