【摘要】 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。更多还原

【Abstract】 Cyclic loading and unloading tests with constant amplitude were designed to analyze the change rules and the correlativity between load/unload response ratio and damage variable,and the change rules of stress-strain hysteresis time,load/unload response ratio,damage variable,the corresponding peak strain of peak stress were analyzed in detail. The results show that:(1) the stress-strain hysteresis time is not a constant during the test,which is obvious larger at the initial stage of the cycle loading and unloading and the stage of approaching destruction.(2) When the rock samples are approaching destruction,the stress-strain hysteresis time,load/unload response ratio,damage variable and the corresponding peak strain of peak stress all have obvious catastrophe,which shows good correlation among the mechanical parameters,and they are closely related to stress state and damage degree of the rock.(3) Considering the effect of rock damage on degree of medium uniformity of rock in cyclic loading and unloading test,correlative equation between load/unload response ratio and damage variable is modified,the result shows that with which can make damage degree of rock clearly described by load/unload response ratio. Research results have good reference value for analyzing the relationship between load/unload response ratio and damage variable,meanwhile,the relevant test methods can provide reference for similar tests.更多还原