刘静^1,2,,
刘盛东²,
曹煜³
1. 中国矿业大学资源与地球科学学院, 江苏徐州 221116
2. 中国矿业大学深部岩土力学与地下工程国家重点实验室, 江苏徐州 221116
3. 安徽惠洲地质安全研究院股份有限公司, 合肥 231202

基金项目: 江苏省自然科学基金项目（BK20170274）和国家重点研发计划（2016YFC0600900）联合资助


详细信息

作者简介: 刘静, 女, 1985年生, 工学博士, 讲师, 从事地电场理论和勘探方面的研究.E-mai:liujing8503@126.com

中图分类号: P319

收稿日期:2016-10-09
修回日期:2017-09-25
上线日期:2018-01-05

Self-potential characteristics in deep rock mass damage based on point discharge mechanism

LIU Jing^1,2,,
LIU ShengDong²,
CAO Yu³
1. School of Resource and Earth Science, China University of Mining and Technology, Xuzhou Jiangsu 221116, China
2. State Key Laboratory of Deep Geomechanics & Underground Engineering, China University of Mining and Technology, Xuzhou Jiangsu 221116, China
3. Anhuihuizhou Geology Security Institute CO, LTD, Hefei 231202, China


MSC: P319

--> Received Date: 09 October 2016
Revised Date: 25 September 2017
Available Online: 05 January 2018


摘要
摘要:在大规模深部岩体损伤过程中发生的裂隙尖端放电现象往往引发地下雷电，对该现象发生机理、表现规律的揭示有助于地震、岩爆等的临灾预报.不同于在岩土体中液固耦合界面上发生的自然电场异常机理，在岩土体内部发生的裂隙尖端放电可谓是引发自然电场异常的另一重要微观机制.本文基于现有裂隙尖端放电的研究成果，详细阐述了裂隙尖端放电发生的过程，解释了岩体损伤过程中自然电场异常产生的微观机理，并结合室内实验成果论述了自电位的主要特征；进行了理论推导，认为在大尺度岩体连续损伤过程中，自电位具有含脉冲状波动并整体下降的特征；开展了原位测试，结果证明人工采掘扰动下的深部岩体连续破坏的过程中，自电位在破坏前期缓慢下降，在破坏过程中会出现脉冲状波动，随着破坏程度的加剧整体呈现波动中下降的规律，与理论推导、室内实验结论都相符.对比室内实验和原位测试成果发现，随着研究目标的空间尺度由mm级别扩展到m的级别，自电位波动的幅值也从数十个mV扩展到数百甚至上千mV，故认为在利用自电位波动规律来预测岩体破坏状态时，须受研究对象的空间尺度的约束.此外，在原位测试中发现，自电位对岩体损伤过程的响应较直流电阻率而言具有时域上的超前优势，并对此现象进行了解释.
关键词: 深部岩体损伤/
裂隙尖端放电/
自电位/
原位检测

Abstract:Electric point discharge occurring in large-scale deep rock mass damage often leads to underground thunder. The study of its mechanism and variation characteristics is helpful to forecast disasters such as earthquakes, rock burst and so on. Electric point discharge in rock is an important microscopic mechanism to internally induce natural electric field anomaly, unlike that happens externally at the liquid-solid interface. Based on the existing research achievements of this phenomenon, detailed description of the point discharge occurrence was given, micro mechanism of the self-potential (SP) anomalies were explained, and its main characteristics were discussed in view of indoor experimental results. By theoretical deduction, it is considered that SP generally descends with pulse shape fluctuations. In-situ scanning experiment conducted in coal mines shows that in the process of deep rock damage induced by excavation, SP curves generally descend accompanied with a number of steep rises and falls, similar to a few of successive pulses, which is in good agreement with theoretical derivation results. Comparing rock sample breaking experiments to deep rock mass damage test, it is found that while the research scale extends from millimeter level to meter level, SP amplitude fluctuation range from several or dozen mV to hundreds or even thousands mV, and this indicates that the SP fluctuation range is related to the spatial scale of the research objectives. In addition, it is found by in-situ test that SP response to the rock mass damage is more advanced than that of the DC resistivity, and the phenomenon is explained.
Key words:Deep rock mass damage/
Electric point discharge/
Self-potential/
In-situ scanning



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