|
|
|
| Damage law and acoustic emission characteristics of three types of hard rocks under low power microwave irradiation |
| CHEN Denghong1，2，WANG Zhipeng1，YUAN Yongqiang1，TANG Yunying3 |
| (1. School of Mining Engineering，Anhui University of Science and Technology，Huainan，Anhui 232001，China；2. Institute of Special Mining，Huainan，Anhui 232001，China；3. Institute of Energy，Hefei Comprehensive National Science Center，Hefei，Anhui 230031，China)
|
|
|
|
|
Abstract Microwave-assisted rock breaking is a new method to achieve efficient and low-damage excavation of hard rocks. There are some differences in the wave absorption capacity，water loss，warming and damage laws of different hard rocks，and the comparative study has important theoretical and engineering significance for accurate and efficient rock breaking. By comparing the mass changes of the specimens before and after pretreatment and microwave radiation，the water loss law of the three types hard rocks were obtained. The whole process of surface temperature rise and fracture of hard rock in microwave field is monitored by infrared thermal imager，and the temperature rise and macro crack propagation characteristics of three types of hard rock under different water content were obtained. The mechanism of hard rock damage effect with increasing radiation energy was elaborated by the changes of longitudinal wave velocity，acoustic emission and SEM microstructure of three types hard rocks under different time of radiation in dry condition. The results show that the effect of water in the lower power microwave radiation within 300 s is as follows：the evaporation of water is the dominant factor in the mass loss of hard rock，water has a significant role in promoting the warming of hard rock，and the degree of influence of water content on the average temperature of the surface area is divided into three stages according to the radiation time “small(0‐50 s)，large(50‐200 s)，stable(200‐300 s)”，in which the saturated water absorption has the most significant effect on the temperature rise and the sandstone and limestone with high saturated water absorption burst in the cavity at 55 s and 240 s respectively. The damage law of different hard rocks with temperature rise in dry state is as follows：the crack propagation of limestone is more obvious than that of sandstone and granite due to large surface temperature difference. COMSOL numerical simulation of continuous radiation for 420，600 and 720 s has a good correlation with the change trend of the damage factor obtained from the experiment. After the three types of hard rock damage，the acoustic emission of the specimens presents three stages of stability，growth and failure，and the uniaxial compressive strength loss is from fast to stable，and the ring count and energy are different in order of magnitude；At the micro scale，the fracture surface of granite and sandstone after 720 s of microwave radiation appears the bonding of molten minerals，which leads to the slow reduction of the longitudinal wave velocity，which explains the internal cause of the damage stabilization；With the increase of the radiation time，the mass loss，the damage factor characterized by the wave velocity，the heating rate and the strength loss obtained by the numerical simulation all show a consistent change law from fast to slow and a “inflection point” from fast to stable. The research results can provide some reference for the differentiation，low energy consumption and high efficiency damage of different hard rocks.
|
|
|
|
|
|
| [1] 卢高明，李元辉，HASSANI F，等. 微波辅助机械破岩试验和理论研究进展[J]. 岩土工程学报，2016，38(8)：1 497–1 506.(LU Gaoming，LI Yuanhui，HASSANI F，et al. Review of theoretical and experimental studies on mechanical rock fragmentation using microwave-assisted approach[J]. Chinese Journal of Geotechnical Engineering，2016，38(8)：1 497–1 506.(in Chinese))
[2] 邵珠山，魏 玮，陈文文，等. 微波加热硬岩与混凝土的研究进展与工程应用[J]. 工程力学，2020，37(5)：140–155.(SHAO Zhushan，WEI Wei，CHEN Wenwen，et al. Research progress and industrial applications of microwave heating processing on rock and concrete[J]. Engineering Mechanics，2020，37(5)：140–155.(in Chinese))
[3] 喻 清，丁德馨，张 炬，等. 微波辐照技术在矿业中的应用现状及发展趋势[J]. 黄金科学技术，2017，25(1)：112–120.(YU Qing，DING Dexin，ZHANG Ju，et al. Application status and development trend of microwave radiation technologyin Mining[J]. Gold Science and Technology，2017，25(1)：112–120.(in Chinese))
[4] 寇青军，方建军，张 铃，等. 微波技术在矿石粉碎中应用的研究进展[J]. 矿产保护与利用，2019，39(4)：172–178.(KOU Qingjun，FANG Jianjun，ZHANG Ling，et al. Research progress in application of microwave technology in ore crushing[J]. Conservation and Utilization of Mineral Resources，2019，39(4)：172–178.(in Chinese))
[5] 王修昌，王晓洁，吴大俊，等. 140 GH毫米波岩石钻探技术研究[J]. 微波学报. DOI：https：//kns. cnki. net/kcms/detail/32. 1493. TN. 20210611. 1417. 002. html.(WANG Xiuchang，WANG Xiaojie，WU Dajun，et al. Study on rock drilling technology of 140 GHz millimeter-wave[J]. Journal of Microwaves. DOI：https：//kns. cnki. net/kcms/ detail/32.1493. TN. 20210611. 1417. 002. html.(in Chinese))
[6] JERBY E，NEROVNY Y，MEIR Y，et al. A silent microwave drill for deep holes in concrete[J]. IEEE Transactions on Microwave Theory and Techniques，2017，66(1)：522–529.
[7] 吴大俊，王晓洁，徐旵东，等. EAST装置电子回旋共振加热系统波纹圆波导研究[J]. 微波学报，2015，31(2)：72–76.(WU Dajun，WANG Xiaojie，XU Handong，et al. Research of circular corrugated waveguide of ECRH system on EAST facility[J]. Journal of Microwaves，2015，31(2)：72–76.(in Chinese))
[8] 乔 兰，郝家旺，李占金，等. 基于微波加热技术的硬岩破裂方法探究[J]. 煤炭学报，2021，46(增1)：241–252.(QIAO Lan，HAO Jiawang，LI Zhanjin，et al. Research on the method of hard rock cracking based on microwave heating technology[J]. Journal of China Coal Society，2021，46(Supp.1)：241–252.(in Chinese))
[9] 胡毕伟，尹土兵，李夕兵. 微波辐射辅助机械冲击破碎硬岩动力学试验研究[J]. 黄金科学技术，2020，28(4)：521–530.(HU Biwei，YIN Tubing，LI Xibing. Experimental study on mechanical impact breaking rock with microwave radiation[J]. Gold Science and Technology，2020，28(4)：521–530.(in Chinese))
[10] 戴 俊，杜文平，吴 涛，等. 微波照射和冲击荷载作用后硬岩裂纹试验研究[J]. 河南理工大学学报：自然科学版，2016，35(3)：420–423.(DAI Jun，DU Wenping，WU Tao，et al. Experimental study of rock fracture after microwave irradiation and impact load[J]. Journal of Henan Polytechnic University：Natural Science，2016，35(3)：420–423.(in Chinese))
[11] 戴 俊，王羽亮，李 涛. 微波照射后花岗岩裂纹扩展规律试验研究[J]. 煤炭工程，2020，52(6)：130–133.(DAI Jun，WANG Yuliang，LI Tao. Experiment on crack propagation law of microwave－irradiated granite[J]. Coal Engineering，2020，52(6)：130–133.(in Chinese))
[12] 戴 俊，王羽亮. 微波辐射下硬岩损伤规律研究[J]. 煤炭工程，2019，51(1)：51–54.( DAI Jun，WANG Yuliang. Experimental study on hard rock damage by microwave irradiation[J]. Coal Engineering，2019，51(1)：51–54.(in Chinese))
[13] 戴 俊，贠菲菲，徐水林，等. 微波照射后玄武岩损伤机制试验研究[J]. 科学技术与工程，2020，20(7)：2 614–2 618.(DAI Jun，YUN Feifei，XU Shuilin，et al. Experimental study on damage mechanism of basalt by microwave irradiation[J]. Science Technology and Engineering，2020，20(7)：2 614–2 618.(in Chinese))
[14] 李元辉，卢高明，冯夏庭，等. 微波加热路径对硬岩破碎效果影响试验研究[J]. 硬岩力学与工程学报，2017，36(6)：1 460–1 468.(LI Yuanhui，LU Gaoming，FENG Xiating，et al. The influence of heating path on the effect of hard rock fragmentation using microwave assisted method[J]. Chinese Journal of Rock Mechanics and Engineering，2017，36(6)：1 460–1 468.(in Chinese))
[15] LU G M，FENG X T，LI Y H，et al. Experiment alI nvesti gation on the effects of microwave treatmenton basalt heating mechanical strength and fragmentation[J]. Rock Mechanics and Rock Engineering，2019，52：2 535–2 549.
[16] LU G M，FENG X T，LI Y H，et al. The microwave-Induced fracturing of hard rock[J]. Rock Mechanics and Rock Engineering，2019，52：3 017–3 032.
[17] YANG B G，GAO M Z，XIE J，et al. Exploration of weakening mechanism of uniaxial compressive strength of deep sandstone under microwave irradiation[J]. Journal of Central South University，2022，29(2)：611–623.
[18] 戴 俊，王羽亮，黄斌斌，等. 水对微波辐射下硬岩劣化效果的影响试验研究. 地下空间与工程学报，2020，16(3)：691–696.(DAI Jun，WANG Yuliang，HUANG Binbin，et al. Experimental study on the effect of water on the degradation of hard rock under microwave irradiation[J]. Chinese Journal of Underground Space and Engineering，2020，16(3)：691–696.(in Chinese))
[19] 谭 赢，刘希灵，赵宇喆. 基于巴西劈裂试验的岩石声发射特性及断口特征分析[J]. 实验力学，2021，36(2)：241–249.(TAN Ying，LIU Xiling，ZHAO Yuzhe. Acoustic emission parameter characteristics fracture morphology analysis of rocks based on Brazilian splitting test[J]. Journal of Experimental Mechanics.2021，36(2)：241–249.(in Chinese))
[20] 刘希灵，刘 周，李夕兵，等. 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(增1)：267–274.(LIU Xiling，LIU Zhou，LI Xibing，et al. Acoustic emission b-values of limestone under uniaxial compression and Brazilian splitting loads[J]. Rock and Soil Mechanics，2019，40(Supp.1)：267–274.(in Chinese))
[21] 中华人民共和国国家标准编写组. GB/T50218—2014 工程岩体分级标准[S]. 北京：中国计划出版社，2014.(The National Standards Compilation Group of the People's Republic of China. GB/T50218—2014. Standard for engineering classification of rock mass[S]. Beijing：China Planning Press，2014.(in Chinese))
[22] 于德浩，宋清波，肖 辉，等. 特定工程岩石坚硬程度划分探讨[C]//国家安全地球物理丛书(十三)——军民融合与地球物理. [S. l.]：[s. n.]，2017：6 224–6 229.(YU Dehao，SONG Qingbo，XIAO Hui，et al. Discussion with the hardness degree of rock for some engineering[C]// National Security Geophysics Series(XIII)--Military-Civilian Integration and Geophysics. [S. l.]：[s. n.]，2017：6 224–6 229.(in Chinese))
[23] 吴顺川，李利平，张晓平. 岩石力学[M]. 北京：高等教育出版社，2021：89–90.(WU Shunchuan，LI Liping，ZHANG Xiaoping. Rock mechanics[M] Beijing：Higher Education Press，2021：89–90.(in Chinese))
[24] 田 军，卢高明，冯夏庭，等. 主要造岩矿物微波敏感性试验研究[J]. 岩土力学，2019，40(6)：2 066–2 074.(TIAN Jun，LU Gaoming，FENG Xiating，et al. Experimental study of the microwave sensitivity of main rock-forming minerals[J]. Rock and Soil Mechanics，2019，40(6)：2 066–2 074.(in Chinese))
[25] 刘汉文. 微波照射下矿物和岩石升温特性与弱化效果研究[硕士学位论文][D]. 南京：南京大学，2018.(LIU Hanwen. Study on temperature rising and wakening effect of minerals and rocks under microwave irradiation[M. S. Thesis][D]. Nanjing：Nanjing University，2018.(in Chinese))
[26] 赵洪宝，王中伟，张 欢，等. 冲击荷载对煤岩内部微结构演化及表面新生裂隙分布规律的影响[J]. 岩石力学与工程学报，2016，35(5)：971–979.(ZHAO Hongbao，WANG Zhongwei，ZHANG Huan，et al. Effects of dynamic loads on development of internal microstructure and distribution of new surface fractures of coal[J]. Chinese Journal of Rock Mechanics and Engineering，2016，35(5)：971–979.(in Chinese))
[27] NOＲOUZI P，BAGHBANAN A，HASHEMOLHOSSEINI H. Effect of coupled triaxial stress-perforation on fracture mechanism and acoustic wave velocity of limestone[J]. Journal of Petroleum Science and Engineering，2018，170：409–421.
[28] 贾海梁，韩 力，孙 强，等. 微波照射冻结石英砂岩热融软化特性及损伤机制研究[J]. 岩石力学与工程学报，2021，40(9)：1 884–1 893.(JIA Hailiang，HAN Li，SUN Qiang，et al. Thawing and softening behaviors and underlying damage mechanisms of frozen quartz sandstone under microwave irradiation[J]. Chinese Journal of Rock Mechanics and Engineering，2021，40(9)：1 884–1 893.(in Chinese))
[29] 吴 刚，王德咏，翟松韬. 单轴压缩下高温后砂岩的声发射特征[J].岩土力学，2012，33(11)：3 237–3 242.(WU Gang，WANG Deyong，ZHAI Songtao. Acoustic emission characteristics of sandstone after high temperature under uniaxial compression[J]. Rock and Soil Mechanics，2012，33(11)：3 237–3 242.(in Chinese))
[30] 赵兴东，唐春安，李元辉，等. 花岗岩破裂全过程的声发射特性研究[J]. 岩石力学与工程学报，2006，25(增2)：3 673–3 678.(ZHAO Xingdong，TANG Chunan，LI Yuanhui，et al. Study on AE characteristics under uniaxial compression loading[J]. Chinese Journal of Rock Mechanics and Engineering，2006，25(Supp.2)：3 673–3 678.(in Chinese)) |
|
|
|
2023, Vol. 42 
