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对砂质泥岩不同加载速率下损伤演化规律与声发射参量特征进行了试验研究,其应变率介于1.0×10-5~1.7×10-3 s-1。研究表明,随着加载速率增大,岩样极限抗压强度有明显升高;随着加载速率增大,AE能量释放形式由孤震型向震群型转变,且高加载速率下AE撞击能量有大幅升高,但AE累计振铃计数明显减少。基于AE累计振铃计数,建立了岩石单轴受载损伤模型,提出了基于岩石损伤的应力-应变本构模型。通过与基于Weibull分布的应力曲线及实测应力曲线对比,试验拟合方程可较好反映岩样单轴加载期间、尤其是较高加载速率下的损伤演化过程。研究内容对于该类岩石不同加载速率下破坏机制、损伤演化规律与前兆信息识别有一定参考价值。
The damage evolution law and acoustic emission parameters under different loading rates of sandy mudstone were studied. The strain rate ranged from 1.0 × 10-5 to 1.7 × 10-3 s-1. The results show that with the increase of loading rate, the ultimate compressive strength of rock specimen increases obviously. With the increase of loading rate, the AE energy release form changes from the isolated quake-type quake swarm and the AE impact energy under high loading rate There has been a substantial increase, but AE cumulative ring count significantly reduced. Based on the AE ring counting, the rock uniaxial loaded damage model was established and the stress-strain constitutive model based on rock damage was proposed. Compared with the stress curves based on the Weibull distribution and the measured stress curves, the experimental fitting equations can better reflect the damage evolution process during the uniaxial loading of rock specimens, especially at higher loading rates. The research contents have certain reference value for the failure mechanism, damage evolution law and precursor information identification of rock under different loading rates.