Fracture Characteristics and Fatigue Damage of Noncoplanar Fractured Rocklike Specimens under Uniaxial Graded Cyclic Loading and Unloading
Fracture Characteristics and Fatigue Damage of Noncoplanar Fractured Rocklike Specimens under Uniaxial Graded Cyclic Loading and Unloading
复制标题
非共面裂隙类岩石试件在单轴梯度循环加载和卸载下的断裂特性和疲劳损伤
DOI：
10.1155/2021/9993195
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发表时间：
2021-05
期刊：
影响因子：
1.7
通讯作者：
Guirong He;Wenkai Wu;Yun Wang;Yong Xue;B. Dai;Zhi-jun Zhang
中科院分区：
文献类型：
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作者：
Guirong He;Wenkai Wu;Yun Wang;Yong Xue;B. Dai;Zhi-jun Zhang
为研究裂隙岩体的断裂特性和疲劳损伤，采用水泥砂浆制备非共面裂隙类岩石试件，进行了分级循环加卸载试验。结果表明，水平裂纹两端是主要的应力集中区，对斜裂纹的起裂有抑制作用。随着裂纹倾角的增大，抑制效果更加明显。在下限应力一定的情况下，随着上限应力的增加，试件的能量耗散增加，在循环的各个阶段变得相对稳定。随着裂纹倾角的增加，能量耗散值的增加幅度减小。磁滞回线形状变化较大的试样，其弹性模量往往会出现较大的波动。随着加载的进行，弹性模量呈下降趋势，阻尼比趋于稳定。阻尼比的变化受动态弹性模量和磁滞回线面积的影响。基于威布尔概率分布函数，可以得到试件损伤变量的演化曲线。该曲线反映了岩石类试件在不同水平循环加卸载作用下的损伤变化趋势。
To study the fracture characteristics and fatigue damage of fractured rock masses, noncoplanar fractured rocklike specimens prepared using cement mortar were used for a graded cyclic loading–unloading test. The results showed that the two ends of the horizontal crack were the main stress concentration areas, and they inhibited crack initiation of the inclined fracture. With increasing crack inclination, the inhibitory effect became more obvious. Under the condition that the lower limit stress is constant, as the upper limit stress increases, energy dissipation of the specimen increases, becoming relatively stable in each stage of the cycle. With increasing crack inclination, the increase in the energy dissipation value decreases. Specimens with large changes in the shape of their hysteresis loop tend to exhibit large fluctuations in the elastic modulus. As the loading progressed, the elastic modulus exhibited a downward trend, and the damping ratio tended to be stable. The change in the damping ratio is affected by the dynamic elastic modulus and area of the hysteresis loop. Based on the Weibull probability distribution function, the evolution curve of the damage variable of the specimen can be obtained. This curve reflects the trend of the damage change of the rocklike specimens under various levels of cyclic loading and unloading.