不同浓度的尾砂胶结充填体破坏过程 声发射特性试验研究*

制备了3种不同质量浓度的充填体试件，进行了单轴压缩声发射试验，分析了不同浓度的充填体力学特性，重点研究了试件破坏过程中的声发射振铃计数、声发射累计撞击数与声发射累计能量的比值(r值)、主频及其相对高频信号激增响应系数特征。研究表明：随着浓度的增加，充填体的峰值强度与弹性模量呈增大趋势，充填体中出现的声发射累计振铃计数越多；r值先升高再持续减小到一个较低值，随着外载荷的增加，进入缓慢升高阶段，峰值前均保持在该阶段。充填体破裂前兆信息在声发射信号主频分布中呈现主频段增多现象，表现为由加载初期的1~2个主频段，在临界主破裂时增多到3~5个主频段；且随着浓度的增加，声发射信号主频频段分布越宽，声发射相对高频信号(160~180 kHz)的激增响应系数呈递减趋势。以上特征可为不同浓度的尾砂胶结充填体稳定性监测、预测提供依据。

Experimental study on AE characteristics of cemented tailings backfill failure process with different concentration

Three kinds of backfill samples with different mass concentrations were prepared, and the uniaxial compression acoustic emission (AE) test was carried out. The mechanical properties of backfill with different mass concentrations were analyzed, focusing on the characteristics of the AE ring count, the ratio of AE cumulative hit number to AE cumulative energy (r value), the main frequency and its relative high frequency signal surge response coefficient. The results show that: with the increase of the concentration, the peak strength and modulus of elasticity of the backfill increase, and the more the cumulative AE ring count appear in the backfill; the r value increases first and then continuously decreases to a lower value, and with the increase of the external load, it enters a slowly increasing stage, and which remains at this stage before the peak value. In the distribution of the main frequency of AE signal, the precursory information of backfill fracture appears the phenomenon of increasing the main frequency segment, which is represented by 1~2 main frequency segments in the initial loading stage and 3~5 main frequency segments in the critical main fracture stage. With the increase of concentration, the main frequency segment of AE signal is wider, and the surge response coefficient of AE relative high frequency signal (160~180 kHz) is decreasing. The above characteristics can provide a basis for the stability monitoring and early predicting of different concentrations of cemented tailings backfill.