| 单轴压缩与劈裂荷载下灰岩声发射b值特性研究 |
| |
| 引用本文： | 刘希灵,刘周,李夕兵,韩梦思.单轴压缩与劈裂荷载下灰岩声发射b值特性研究[J].岩土力学,2019,40(Z1):267-274. |
| |
| 作者姓名： | 刘希灵 刘周 李夕兵 韩梦思 |
| |
| 作者单位： | 中南大学 资源与安全工程学院，湖南 长沙 410083 |
| |
| 基金项目： | 国家重点研发计划（No.2016YFC0600706）；中南大学研究生自由探索创新项目（No.2018zzts757） |
| |
| 摘 要： | 通过开展灰岩巴西劈裂和单轴压缩声发射试验，探讨两种加载方式下岩石破裂声发射b值特性及b值计算影响因素。结果表明，累积计算b值拟合度高，误差较小；步距为5 dB时不同门槛值下b值随时间变化的总体规律基本一致，选择5 dB的步距和40 dB的门槛值计算b值比较合理，能够降低非岩石破裂信号对b值变化的影响。由动态b值的波动程度可以看出，在劈裂荷载下灰岩损伤演化过程可分为3个阶段，即(0～40%)?c(?c为峰值强度)、(40%～90%)?c和(90%～100%)?c，而在单轴加载下可分为：(0～80%)?c和(80%～100%)?c两个阶段，且不同阶段岩石内部损伤的程度不同。在裂纹扩展阶段，相比单轴加载，劈裂荷载下动态b值增加较为稳定，但在整个破坏过程中劈裂荷载下动态b值波动更大，在单轴压缩和劈裂加载方式下b值的大小取决于灰岩破裂面上的结构性质及破裂模式。
|
| 关 键 词： | 岩石声发射 b值 单轴压缩 巴西劈裂 影响因素 |
| 收稿时间： | 2018-11-27 |
Acoustic emission b-values of limestone under uniaxial compression and Brazilian splitting loads |
| |
| LIU Xi-ling,LIU Zhou,LI Xi-bing,HAN Meng-si.Acoustic emission b-values of limestone under uniaxial compression and Brazilian splitting loads[J].Rock and Soil Mechanics,2019,40(Z1):267-274. |
| |
| Authors: | LIU Xi-ling LIU Zhou LI Xi-bing HAN Meng-si |
| |
| Institution: | School of Resources and Safety Engineering, Central South University, Changsha Hunan 410083, China |
| |
| Abstract: | Through the acoustic emission monitoring on two loading modes i.e. Brazilian splitting and uniaxial compression of limestone, the b-value characteristics of rock rupture and the impact factors are discussed. The results show that cumulative calculation of b-value has a high fitting degree and small error. When the step length is 5 dB, the overall change trend of b-value with time under different threshold values is similar. It shows that the calculation of b-value is more reasonable with the step length of 5 dB and threshold value of 40 dB, which can reduce the influence of non-rock fracture signals on the variation of b-value. Additionally, based on the fluctuation characteristics of the dynamic b-value, it can be seen that under the splitting load, the damage evolution of limestone can be divided into three stages: (0-40%)?c, (40%-90%)?c, and (90%-100%)?c. Under uniaxial compression load, the damage evolution of limestone can be divided into two stages: (0-80%)?c and (80%-100%)?c (?c is the peak strength). At different stages of rock damage, it presents different levels of damage in the rocks. In the crack propagation stage, compared with uniaxial compression load, the dynamic b-value increases steadily during crack growth process under Brazilian splitting load condition, and the dynamic b-value fluctuates greatly during the whole failure process. Through the experiments in this paper, it shows that the variation of b-value depends on the structural property and failure modes of the limestone fracture surface. |
| |
| Keywords: | rock acoustic emission b-value uniaxial compression Brazilian splitting impact factors |
| 本文献已被 CNKI 等数据库收录！ |
| 点击此处可从《岩土力学》浏览原始摘要信息 |
| 点击此处可从《岩土力学》下载免费的PDF全文 |
|
