|
|
|
| Effects of dynamic loads on internal microstructure of coal by nuclear magnetic resonance(NMR) |
| ZHAO Hongbao1,2,WANG Zhongwei1,HU Guilin1 |
(1. School of Resources and Safety Engineering,China University of Mining and Technology,Beijing 100083,China;
2. State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology,Beijing 100083,China) |
|
|
|
|
Abstract The tests on raw coal and moulded coal specimens under impact loads were performed with the drop hammer impact test device developed in-house. The effects of the number of impact loading,the magnitude of the energy of a single impact,the accumulative effects of impact energy and the energy sequence of impact on the internal micro-structure of coal were studied according to the distribution of T2 spectrum of specimens measured with the nuclear magnetic resonance(NMR) analyzer. The results show that there are some differences between T2 spectrum distributions of raw coal specimen and moulded coal specimen. The quantity and size of internal micro-structure of specimens,especially of raw coal specimens,were increased due to the dynamic loads. The total quantity of internal micro-structure of coal increased nonlinearly with the increase of impact times with a trend of rapid increasing,gentle development and sharp increasing,and increased nonlinearly with the increasing of energy of single impact. Due to the coupling effects of the threshold and absorption rate of impact energy,the accumulative effect of impact loads on internal micro-structure of coal is also nonlinear and has a decreasing trend after the first increase. The accumulative effects of impact loads cannot be simplified as the increasing of the impact energy. The total quantity of internal micro-structure of coal is more sensitive under decreasing cyclic loading than increasing process,so the reservoir can be efficiently stimulated by adjusting the construction sequence in the engineering field.
|
|
|
|
|
|
[1] 赵洪宝,尹光志. 煤样初始内部结构对瓦斯流动特性的影响[J]. 重庆大学学报,2010,33(9):74–78.(ZHAO Hongbao,YIN Guangzhi. The influence of initial-internal structure of coal sample on gas flow characteristic[J]. Journal of Chongqing University,2010,33(9):74–78.(in Chinese))
[2] 许 江,袁 梅,李波波,等. 煤的变质程度、孔隙特征与渗透率关系的试验研究[J]. 岩石力学与工程学报,2012,31(4):681–687.(XU Jiang,YUAN Mei,LI Bobo,et al. Experimental study on the relationship of metamorphic grade of coal,pore characteristics,and permeability[J]. Chinese Journal of Rock Mechanics and Engineering,2012,31(4):681–687.(in Chinese))
[3] 许 江,程立朝,谭皓月,等. 原生裂纹对煤岩剪切破坏宏细观演化规律的影响研究[J]. 岩石力学与工程学报,2013,32(1):677–685.(XU Jiang,CHENG Lichao,TAN Haoyue,et al. Effects of original cracks on macro-meso evolution law of raw coal shear failure[J]. Chinese Journal of Rock Mechanics and Engineering,2013,32(1):677–685.(in Chinese))
[4] WANG S,ELSWORTH D,LIU J. Permeability evolution during progressive deformation of intact coal and implications for instability in underground coal seams[J]. International Journal of Rock Mechanics and Mining Sciences,2013,58(1):34–45.
[5] 尹光志,李广治,赵洪宝,等. 煤样全应力–应变过程中瓦斯流动性试验研究[J]. 岩石力学与工程学报,2010,29(1):170–175.(YIN Guangzhi,LI Guangzhi,ZHAO Hongbao,et al. Experimental research on gas flow properties of coal specimens in complete stress-strain process[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(1):170–175.(in Chinese))
[6] 尹光志,李小双,赵洪宝,等. 瓦斯压力对突出煤瓦斯渗流影响试验研究[J]. 岩石力学与工程学报,2009,28(4):697–702.(YIN Guangzhi,LI Xiaoshuang,ZHAO Hongbao,et al. Experimental study of effect of gas pressure on gas seepage of outburst coal[J]. Chinese Journal of Rock Mechanics and Engineering,2009,28(4):697–702.(in Chinese))
[7] 许 江,苏小鹏,程立朝,等. 压剪应力作用下含瓦斯原煤细观裂隙演化特征试验研究[J]. 岩石力学与工程学报,2014,33(3):458–467.(XU Jiang,SU Xiaopeng,CHENG Lichao,et al. Evolution characteristics of meso-cracks of gas-filled raw coal under compression-shear stress[J]. Chinese Journal of Rock Mechanics and Engineering,2014,33(3):458–467.(in Chinese))
[8] PERERA M S A,RANJITH P G,ChOI S K,et al. Investigation of temperature effect on permeability of naturally fractured black coal for carbon dioxide movement:an experimental and numerical study[J]. Fuel,2012,94(1):596–605.
[9] YU Y,LIANG W,HU Y,et al. Study of micro-pores development in lean coal with temperature[J]. International Journal of Rock Mechanics and Mining Sciences,2012,51(4):91–96.
[10] 孟巧荣,赵阳升,于艳梅,等. 不同温度下褐煤裂隙演化的显微CT试验研究[J]. 岩石力学与工程学报,2010,29(12):2 475–2 483. (MENG Qiaorong,ZHAO Yangsheng,YU Yanmei,et al. Micro-CT experimental study of crack evolution of lignite under different temperatures[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(12):2 475–2 483.(in Chinese))
[11] AKBARZADEH H,CHALATURNYK R J. Structural changes in coal at elevated temperature pertinent to underground coal gasification:a review[J]. International Journal of Coal Geology,2014,131:126–146.
[12] 周军平,鲜学福,李晓红,等. 吸附不同气体对煤岩渗透特性的影响[J]. 岩石力学与工程学报,2010,29(11):2 256–2 262.(ZHOU Junping,XIAN Xuefu,LI Xiaohong,et al. Effect of different adsorptional gases on permeability of coal[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(11):2 256–2 262.(in Chinese))
[13] MASOUDIAN M S,AIREY D W,EL-ZEIN A. Experimental investigations on the effect of CO2 on mechanics of coal[J]. International Journal of Coal Geology,2014,128(3):12–23.
[14] HOL S,GENSTERBLUM Y,MASSAROTTO P. Sorption and changes in bulk modulus of coal—experimental evidence and governing mechanisms for CBM and ECBM applications[J]. International Journal of Coal Geology,2014,128/129(3):119–133.
[15] 赵 东,赵阳升,冯增朝. 结合孔隙结构分析注水对煤体瓦斯解吸的影响[J]. 岩石力学与工程学报,2011,30(4):686–692.(ZHAO Dong,ZHAO Yangsheng,FENG Zengchao. Analysis of effect of water injection on methane desorption in coal combining pore structure[J]. Chinese Journal of Rock Mechanics and Engineering,2011,30(4):686–692.(in Chinese))
[16] ZHAO H B,WANG Z W. Experimental study on influences on microstructure of coal block caused by dynamic impact[J]. Nature Changes,2014,1(2):1–6.
[17] 李恒乐,秦 勇,张永民,等. 重复脉冲强冲击波对肥煤孔隙结构影响的实验研究[J]. 煤炭学报,2015,40(4):915–921.(LI Hengle,QIN Yong,ZHANG Yongmin,et al. Experimental study on the effect of strong repetitive pulse shockwave on the pore structure of fat coal[J]. Journal of China Coal Society,2015,40(4):915–921.(in Chinese))
[18] 丁雁生,陈 力,谢 燮,等. 低渗透油气田“层内爆炸”增产技术研究[J]. 石油勘探与开发,2001,28(2):90–96.(DING Yansheng,CHEN Li,XIE Xie,et al. On the stimulation with exploding in fracture in low permeability reservoir[J]. Petroleum Exploration and Development,2001,28(2):90–96.(in Chinese))
[19] 徐 鹏,程远方,刘新云,等. 低渗透油气藏爆炸压裂模拟试验及裂缝分形特征[J]. 石油勘探与开发,2013,40(5):636–640.(XU Peng,CHENG Yuanfang,LIU Xinyun,et al. Explosive fracturing simulation experiment for low permeability reservoirs and fractal characteristics of cracks produced by explosive fracturing[J]. Petroleum Exploration and Development,2013,40(5):636–640.(in Chinese))
[20] 李夕兵. 岩石动力学基础与应用[M]. 北京:科学出版社,2014:176–192.(LI Xibing. Rock dynamics fundamentals and applications[M]. Beijing:Science Press,2014:176–192.(in Chinese))
[21] ZHANG Q B,ZHAO J. A review of dynamic experimental techniques and mechanical behaviour of rock materials[J]. Rock Mechanics and Rock Engineering,2013,47(4):1 411–1 478.
[22] 周科平,李杰林,许玉娟,等. 冻融循环条件下岩石核磁共振特性的试验研究[J]. 岩石力学与工程学报,2012,31(4):731–737.(ZHOU Keping,LI Jielin,XU Yujuan,et al. Experimental study of NMR characteristics in rock under freezing and thawing cycles[J]. Chinese Journal of Rock Mechanics and Engineering,2012,31(4):731–737.(in Chinese))
[23] 朱和玲,周科平,张亚民,等. 基于核磁共振技术的岩体爆破损伤试验研究[J]. 岩石力学与工程学报,2013,32(7):1 410–1 416. (ZHU Heling,ZHOU Keping,ZHANG Yamin,et al. Experimental study of rock damage by blasting based on nuclear magnetic resonance technique[J]. Chinese Journal of Rock Mechanics and Engineering,2013,32(7):1 410–1 416.(in Chinese))
[24] GUO R,MANNHARDT K,KANTZAS A. Characterizing moisture and gas content of coal by low-field NMR[J]. Journal of Canadian Petroleum Technology,2007,46(10):49–54.
[25] 姚艳斌,刘大猛,蔡益栋,等. 基于NMR和X-CT的煤的孔裂隙精细定量表征[J]. 中国科学:地球科学,2010,40(11):1 598–1 607. (YAO Yanbin,LIU Dameng,CAI Yidong,et al. Advanced characterization of pores and fractures in coals by nuclear magnetic resonance and X-ray computed tomography [J]. Chinese Science:Earth Science,2010,40(11):1 598–1 607.(in Chinese)
[26] YAO Y B,LIU D M,XIE S B. Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method[J]. International Journal of Coal Geology,2014,131:32–40.
[27] 周世宁,林柏泉. 煤层瓦斯赋存与流动理论[M]. 北京:煤炭工业出版社,1998:25–46.(ZHOU Shining,LIN Boquan. The theory of gas flow and storage in coal seams[M]. Beijing:China coal Industry Publishing House,1998:25–46.(in Chinese))
[28] 周科平,胡振襄,高 峰,等. 基于核磁共振技术的大理岩三轴压缩损伤规律研究[J]. 岩土力学,2014,35(11):3 117–3 122.(ZHOU Keping,HU Zhenxiang,GAO Feng,et al. Study of marble damage laws under triaxial compression condition based on nuclear magnetic resonance technique[J]. Rock and Soil Mechanics,2014,35(11):3 117–3 122.(in Chinese))
|
|
|
|