Loading rate effect on uniaxial compressive strength behavior and acoustic emission properties of cemented tailings backfill
Loading rate effect on uniaxial compressive strength behavior and acoustic emission properties of cemented tailings backfill
复制标题
加载速率对胶结尾矿充填体单轴抗压强度行为和声发射特性的影响
DOI：
10.1016/j.conbuildmat.2019.04.082
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发表时间：
2019-07-20
影响因子：
7.4
通讯作者：
Xue, Gaili
中科院分区：
文献类型：
--
作者：
Cao, Shuai;Yilmaz, Erol;Xue, Gaili
为了了解胶结尾砂充填体在动态载荷作用下的质量和行为，必须准确地确定加载速率的变化对有效的矿山充填设计的影响。以某金矿分级尾砂和胶凝材料为原料，分别采用50N/S、100N/S、150N/S和200N/S四种加载速率，对固化180d后的胶凝材料试件的抗压强度和声发射特性进行了研究，并在机械试验机(GAW-2000型)和声发射设备(PCI2型)上进行了单轴压缩试验。试验结果表明：(1)加载速率对CTB试件的长期强度行为有增强作用，CTB试件的峰值抗压强度与加载速率之间存在幂函数关系。充填体的应力状态在峰值抗压强度之前呈阶梯状增长，整个过程呈现出“涌-稳-涌-稳”的多循环过程；(2)加载过程中，环数分布具有规律性的峰距效应，累计环数也呈“阶梯状”趋于稳定。(3)随着加载速率的增加，CTB的破坏模式由拉剪混合(以剪应力为主)向X型剪切破坏转变。最终，这项实验工作的基本结果将为研究CTB试件的动态特性提供科学参考。(C)2019爱思唯尔有限公司。保留所有权利。
To understand the quality and behavior of cemented tailings backfill (CTB) subjected to dynamic loads, the influence of change in the rate of loading should be accurately determined for an efficient mine fill design. In this study, the compressive strength behavior and acoustic emission (AE) characteristics of 180-day cured CTB samples are investigated by using four different loading rates: 50 N/s, 100 N/s, 150 N/s, and 200 N/s. Samples were prepared with the classified tailings and cementitious material of a gold mine as raw materials and subjected to the uniaxial compressive test using mechanical testing machine (GAW-2000) and AE equipment (PCI-2). Experimental results indicate that: (1) the loading rate has a strengthening effect on long-term strength behavior of CTB samples, and there is a power function between peak compressive strength of CTB samples and loading rate. The stress state of the backfill mass is "stepped" growth before the peak compressive strength, and the whole process displays a multi-cycle of "surge-steady-surge-steady"; (2) during the loading process, the ring count distribution has a regular peak-spacing effect, and the cumulative ring counts are also "stepped" and inclined to be stable. (3) With the increase of loading rate, the failure mode of CTB is a transition from tensile and shear mixing (mainly shear stress) to X-type shear failure. Ultimately, the essential findings of this experimental work will provide a scientific reference for studying the dynamic characteristics of CTB samples. (C) 2019 Elsevier Ltd. All rights reserved.