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粗粒料在变形和颗粒破碎过程中伴随着明显的声发射(AE),通过监测粗粒料在外力作用下的声发射信号特征可用来研究其力学机制。为探讨不同应力路径下绢云母片岩粗粒料声发射规律,采用改装设计的大型三轴试验机,对绢云母片岩粗粒料分别开展了常规三轴固结排水、等p(体应力)和等q(偏应力)应力路径试验,同时监测其声发射信号。研究表明,对于粗粒料的声发射必须考虑颗粒间的滑动摩擦、翻滚摩擦、颗粒破碎这3种细观机制。不同围压、不同应力水平对颗粒间的滑移、翻滚以及颗粒破碎活动影响较大,因此,在不同阶段,摩擦型AE与破碎型AE所占比例各不相同。在等p路径下,当累计声发射信号出现拐点时,可判断其为应变软化点。等q试验产生的累计AE计数与累计AE能量计数要比等p试验的累计AE计数和累计AE能量计数少一个量级,说明等p试验状态下的声发射要比等q试验活跃。等p试验中,随着体应力逐渐增大,累计AE参量增长率逐渐增大,而等q试验中,随着偏应力逐渐增大,累计AE参量增长率逐渐降低。
Coarse aggregates are accompanied by obvious acoustic emission (AE) during the process of deformation and particle crushing. The mechanical mechanism can be studied by monitoring the AE signal characteristics of coarse aggregates under external force. In order to investigate the acoustic emission law of sericite schist in different stress paths, a large triaxial testing machine with modified design was used to carry out conventional triaxial consolidation drainage, equal p (body stress) and Q (stress) stress path test, while monitoring its acoustic emission signal. The research shows that for the acoustic emission of coarse aggregate, the three kinds of meso-mechanisms such as sliding friction, rolling friction and particle breaking must be considered. Different confining pressures and different stress levels have a great influence on the slippage and tumbling of the particles and the particle crushing activities. Therefore, the proportions of the tribo-type AE and the crushing type AE vary at different stages. Under the equal p path, when the accumulated acoustic emission signal appears inflection point, it can be judged as strain softening point. Et al. The cumulative AE count and accumulated AE energy count produced by the trial were one order of magnitude less than the cumulative AE count and the cumulative AE energy count of the same p-test, indicating that the acoustic emission at the p-test state was more pessimistic than the q test. In other tests, with the gradual increase of body stress, the cumulative growth rate of AE parameters gradually increased. However, with the increase of deviatoric stress, the cumulative AE parameter growth rate gradually decreased.