单轴分级循环加载条件下砂岩疲劳变形特性与损伤模型研究

发布时间：2018-06-12 09:41

本文选题：分级循环荷载 + 岩石力学　；参考：《中国矿业大学学报》2017年01期

【摘要】：利用MTS815电液伺服试验机对两组砂岩试样进行了单轴分级循环加卸载试验,分析了分级循环加卸载应力-应变曲线特征和分级循环加卸载下岩石疲劳损伤演化过程,建立了循环加卸载条件下轴向应变与循环数目之间的理论模型,并推导了评价岩石损伤程度的损伤变量演化方程.结果表明:理论模型可以作为岩石循环加卸载条件下的破坏准则,试验结果与理论值之间相关度超过98%,同时,其逆函数可以实现对岩石疲劳寿命的预测;疲劳损伤演化方程可以衡量循环加卸载过程中疲劳损伤的发展水平;疲劳循环上限应力值是决定岩石疲劳寿命的关键因素,随着上限应力的提高,岩石的疲劳寿命呈现几何级数下降.
[Abstract]:Using MTS815 electro-hydraulic servo testing machine, uniaxial cyclic loading and unloading tests were carried out on two groups of sandstone samples. The characteristics of stress-strain curves of graded cyclic loading and unloading and the fatigue damage evolution process of rock under graded cyclic loading and unloading were analyzed. A theoretical model between the axial strain and the number of cycles under cyclic loading and unloading is established, and the damage variable evolution equation for evaluating the damage degree of rock is derived. The results show that the theoretical model can be used as the failure criterion under cyclic loading and unloading conditions, and the correlation between the test results and the theoretical values is more than 98. At the same time, the inverse function of the model can be used to predict the fatigue life of rock. The fatigue damage evolution equation can measure the development level of fatigue damage during cyclic loading and unloading, the upper limit stress of fatigue cycle is the key factor to determine the fatigue life of rock, and with the increase of upper limit stress, The fatigue life of rock decreases exponentially.
【作者单位】：中国矿业大学深部煤炭资源开采教育部重点实验室矿业工程学院;西弗吉尼亚大学工程与矿物资源学院;
【基金】：国家自然科学基金项目(51574220) 江苏省高校优势学科建设工程项目(SZBF2011-6-B35) 中央高校基本科研业务费专项资金项目(2014ZDPY21)
【分类号】：TU45

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