利用TAW-2000D电液伺服试验机以及SDAES数字声发射检测仪对大理岩进行两种不同应力路径的单轴循环加卸载,研究了不同应力条件下试件的抗压强度、变形、声发射特征以及加卸载响应比的变化情况.研究结果表明:相比单轴压缩条件,恒下限和恒差值加卸载作用均能对岩样的抗压强度有一定的强化作用,强化增幅分别为18.5 %和31.4 %;恒差值加卸载下岩样的变形以弹性变形为主,而恒下限加卸载下岩样的变形存在较大部分塑性变形,且随着循环次数的增多其塑性变形越来越大;恒下限加卸载下岩样内部裂隙的发育程度相比恒差值加卸载要更高;加卸载响应比的异常变化可以作为岩石即将失稳的判据,且相比恒下限,恒差值加卸载条件下由加载过程主导的损伤阶段更早,在破坏前LUUR的变化更加剧烈.%Using TAW - 2000D electro-hydraulic servo testing machine and SDAES digital acoustic emission detector test marble with two different stress path of uniaxial cyclic loading and unloading,the compressive strength, deformation,acoustic emission characteristics and the response ratio of loading and unloading under different stress conditions are studied.The result show that:Compared with uniaxial compression,both the constant lower limit and constant difference loading and unloading effect can enhance the peak strength of rock samples,and the increase is 18.5 % and 31.4 % respectively;The deformation of rock samples under constant difference loading and unloading is mainly elastic deformation,while the deformation of rock samples under constant lower limit loading and unloading has large plastic deformation, and the plastic deformation increases with the increase of cycle times; The development degree of the internal micro cracks in the rock sample under the constant lower limit loading and unloading is higher than the constant difference loading and unloading;The abnormal change of LUUR can be used as the criterion for rock instability; Compared with the constant lower limit, the damage stage dominated by the loading process is earlier under the condition of constant difference loading and unloading,and the change of LUUR is more intense before the damage.
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