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为了深入分析岩石在循环加卸载作用过程中的加卸载响应比和损伤变量的变化规律及二者的相关关系,设计并开展砂岩的常幅循环加卸载试验,详细分析试验过程中的应力–应变滞后时间差、加卸载响应比、损伤变量、上限应力对应的应变峰值的变化规律。结果表明:(1)循环加卸载过程中,应力–应变滞后时间差并不是一个常数,在循环加卸载的初期和临近破坏阶段,滞后时间差明显较大;(2)岩样在临近破坏时,应力–应变滞后时间差、加卸载响应比、损伤变量和上限应力对应的应变峰值均存在明显突变,说明岩石的各项力学参数具有较好的相关性,而且与岩石所处的应力状态及损伤程度密切相关;(3)考虑循环加卸载的损伤作用对岩石介质均匀程度的影响,修正了加卸载响应比与损伤变量相关关系式,结果表明,采用修正的关系式,可以用加卸载响应比较好地描述岩样的损伤程度。研究成果对岩石加卸载响应比及其与损伤变量关系的分析具有较好的参考价值,同时,相关试验分析方法也可以为类似试验提供参考。
In order to further analyze the loading-unloading response ratio and the variation law of damage variables during the process of cyclic loading and unloading and the correlation between them, the cyclic loading and unloading test of sandstone was designed and carried out. The stress-strain Lag time difference, load-unload response ratio, damage variable, upper limit stress corresponding strain peak variation. The results show that: (1) The stress-strain hysteresis time difference is not a constant in the process of cyclic loading and unloading, and the lag time difference is obviously larger in the initial stage and adjacent destruction stage of cyclic loading and unloading; (2) - Strain lag time difference, loading-unloading response ratio, damage variables and upper limit stress strain peaks are obvious mutations, indicating that the mechanical parameters of rock has a good correlation, but also with the rocks where the stress state and damage are close (3) Considering the effect of cyclic loading and unloading damage on the uniformity of rock media, the correlation between loading and unloading response ratio and damage variables was corrected. The results show that the modified relation can be used to better unload response Describe the degree of rock sample damage. The research results have good reference value for the analysis of rock loading and unloading response ratio and its relationship with damage variables. At the same time, the related experimental analysis methods can also provide reference for similar experiments.