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基于CT扫描的循环载荷作用下岩石损伤、 破坏过程及声发射表征研究

发表时间:2018-03-30  浏览量:848  下载量:146
全部作者: 段东,张向东,刘利斌,赵钰挺
作者单位: 太原理工大学矿业工程学院
摘 要: 采用循环加卸载方式研究岩石在不同加载阶段岩石孔隙率的变化特征、岩石内部微破坏的变化规律及破坏与声发射之间的关系。研究表明,1)辉长岩第一次加载至约峰值载荷的90%时,加载前后孔隙率变化非常小,表现出很强的弹性回弹特征。当达到峰值载荷的90%时裂纹起裂,卸载后为裂纹的稳定扩展阶段。在扩展过程中,裂纹的长度和宽度逐渐变小,当遇到较大坚硬颗粒时,裂纹易发生分叉和不连通现象,同时裂纹也变小,颗粒越大,对裂纹的影响也越大。2)声发射事件空间分布大体上已经反映了宏观裂纹情况,声发射累积事件能很好地反映裂纹发育过程,声发射丛集区是裂纹起裂区域。3)通过对声发射事件不同区域的计算机断层成像(computed tomography,CT)扫描技术分析发现,声发射较多区域的孔隙率高于声发射较少区域,再次证明了声发射与岩石损伤、微破坏之间有着较高的一致性。4)通过声发射振铃计数,建立了声发射与破坏之间的关系,裂纹越宽,振铃计数越大,依此关系,大体上可以推测出贯通裂纹的扩展过程。声发射和CT扫描相结合丰富了岩石破坏机理研究手段,可以准确地分析岩石内部裂纹的扩展规律,同时,通过CT扫描建立声发射与破坏之间的关系,促进了声发射技术的应用。
关 键 词: 采矿工程;破坏过程;循环载荷;CT扫描;声发射时空分布;声发射表征
Title: Research on process of damage and failure for rock and characterization of acoustic emission by cyclic loading based on CT scan
Author: DUAN Dong, ZHANG Xiangdong, LIU Libin, ZHAO Yuting
Organization: College of Mining Engineering, Taiyuan University of Technology
Abstract: The change features of rock porosity and the relationship between change law and destruction of micro-fracture in rock and acoustic emission are studied by using loading and unloading cycles with the rock at different loading stages. The results showed that: 1) when first loaded to about 90% of the peak load, porosity change was very small before and after loading which showed gabbro had a strong elastic rebound characteristic. The gabbro crack began cracking when the load reached 90% of the peak load, it was a stable extension stage of crack after unloading. In the process of crack extension, crack length and width became smaller. Crack was liable to come up a phenomena of bifurcation disconnected when there were large and hard particles, and crack also decreased at the same time. The bigger the particles were, the greater effect would made on crack. 2) Spatial distribution of acoustic emission events had reflected the macroscopic crack situation in general. Accumulation of acoustic emission events could well reflect the crack development process. The acoustic emission cluster district was the area of initiation of crack. 3) By analyzing computed tomography (CT) scan technology in different areas of the acoustic emission events, we found that porosity of the area with more acoustic emission events was higher than that of the area with less acoustic emission events. Once again it proved that there was a high consistency between acoustic emission and the rock damage and micro fracture. 4) The relationship between acoustic emission and destruction was established based on acoustic emission ringing counting of which the wider crack was, the more the ringing counted. According to this relationship we could infer the extension process of penetrating crack in general. Combination of acoustic emission and CT enriched the means of the study of the failure mechanism of rocks, and the internal crack extension law of rock can be accurate analysis at the same time. Establishment of relationship between acoustic emission and destruction by CT can promote the application of acoustic emission technology.
Key words: mining engineering; failure process; cyclic loading; CT scan; temporal and spatial distribution of acoustic emission; characterization of acoustic emission
发表期数: 2018年3月第6期
引用格式: 段东,张向东,刘利斌,等. 基于CT扫描的循环载荷作用下岩石损伤、 破坏过程及声发射表征研究[J]. 中国科技论文在线精品论文,2018,11(6):601-610.
 
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