Collapse filling-based technology of weakening and danger-solving by staged fracturing in hard roof

Authors

ZHENG Kaige, School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China; Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
YANG Junzhe, Shendong Coal Group Corporation Limited, China Energy, Shenmu 719315, China
LI Bingang, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
LI Yanjun, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
DAI Nan, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
YANG Huan, Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China

Abstract

The working face is easy to induce dynamic disasters such as rock burst, coal and gas outburst, mine earthquake and hurricane in goaf under the condition of hard roof, which seriously threatens the safety of mine production. the pre-weakening and risk-solving technology of staged fracturing in hard roof is proposed based on the mode of advanced weakening by staged fracturing through open holes, combined with the synergetic support concept with "fracturing collapse body+coal pillar+load-bearing rock layer". By using the methods of theoretical analysis, technical research and development and engineering application, the crisis mechanism of advanced weakening of the staged fracturing in roof was explored, and the quantitative judgment formula for the formation of stable collaborative support system was developed, and the engineering application was carried out in Baode Coal Mine in Hedong Coalfield. The results show that the maximum hydraulic fracturing pressure is 22.43 MPa, the maximum fracture pressure drop is 6.17 MPa, and the pressure drop above 3.0 MPa is more than 167 times in three boreholes by implementing the hydraulic fracturing weakening technology of roof section according to the selected of fracturing target layer by determination formula. Through the analysis of the working face pressure before and after fracturing, the roof weighting step distance, dynamic load coefficient and average pressure after fracturing are reduced by 35.02%, 14.29% and 13.87% respectively, and the deformation along the roadways is effectively controlled. It is verified that staged fracturing can form artificial cooperative support system, realize the weakening and solution of dynamic disasters of hard roof, and provide technical and equipment support for the prevention and control of strong mine pressure disasters of roof under similar geological conditions.

Keywords

hard roof, rock burst, dynamic disasters, staged hydraulic fracturing, collaborative support, advance weakening and crisis-solving, dynamic factor, Baode Coal Mine in Hedong Coalfield

DOI

10.3969/j.issn.1001-1986.2021.05.009

Recommended Citation

ZHENG Kaige, YANG Junzhe, LI Bingang, et al. (2021) "Collapse filling-based technology of weakening and danger-solving by staged fracturing in hard roof," Coal Geology & Exploration: Vol. 49: Iss. 5, Article 10.
DOI: 10.3969/j.issn.1001-1986.2021.05.009
Available at: https://cge.researchcommons.org/journal/vol49/iss5/10

Reference

[1] KANG Hongpu, XU Gang, WANG Biaomou, et al. Forty years development and prospects of underground coal mining and strata control technologies in China[J]. Journal of Mining and Strata Control Engineering, 2019, 1(1): 013501. 康红普, 徐刚, 王彪谋, 等. 我国煤炭开采与岩层控制技术发展40 a及展望[J]. 采矿与岩层控制工程学报, 2019, 1(1): 013501.

[2] JIN Zhongming, XU Linsheng. Hard roof control in coal mines[M]. Beijing: China Coal Industry Publishing House, 1994: 30–35. 靳钟铭, 徐林生. 煤矿坚硬顶板控制[M]. 北京: 煤炭工业出版社, 1994: 30–35.

[3] 岑传鸿. 顶板灾害防治[M]. 徐州: 中国矿业大学出版社, 1994.

[4] ZHU Guangan, DOU Linming, WANG Changbin, et al. Experimental study of rock burst in coal samples under overstress and true triaxial unloading through passive velocity tomography[J]. Safety Science, 2019, 117: 388–403.

[5] QI Qingxin, OUYANG Zhenhua, ZHAO Shankun, et al. Study on types of rock burst mine and prevention methods in China[J]. Coal Science and Technology, 2014, 42(10): 1–5. 齐庆新, 欧阳振华, 赵善坤, 等. 我国冲击地压矿井类型及防治方法研究[J]. 煤炭科学技术, 2014, 42(10): 1–5.

[6] 齐庆新, 窦林名. 冲击地压理论与技术[M]. 徐州: 中国矿业大学出版社, 2008.

[7] DOU Linming, ZHAO Congguo, YANG Siguang, et al. Prevention and control of rock burst in coal mine[M]. Xuzhou: China University of Mining and Technology Press, 2006. 窦林名, 赵从国, 杨思光, 等. 煤矿开采冲击矿压灾害防治[M]. 徐州: 中国矿业大学出版社, 2006.

[8] LI Nan, HUANG Bingxiang, ZHANG Xin, et al. Characteristics of micro seismic waveforms induced by hydraulic fracturing in coal seam for coal rock dynamic disasters prevention[J]. Safety Science, 2019, 115: 188–198.

[9] 史元伟, 宁宇, 魏景云. 采煤工作面围岩控制原理和技术(下)[M]. 徐州: 中国矿业大学出版社, 2003: 108–125.

[10] FENG Yanjun, KANG Hongpu. Test on hard and stable roof control by means of direction hydraulic fracturing in coal mine[J]. Chinese Journal of Rock Mechanics and Engineering, 2012, 31(6): 1148–1155. 冯彦军, 康红普. 定向水力压裂控制煤矿坚硬难垮顶板试验[J]. 岩石力学与工程学报, 2012, 31(6): 1148–1155.

[11] KANG Hongpu, FENG Yanjun. Monitoring of stress change in coal seam caused by directional hydraulic fracturing in working face with strong roof and its evolution[J]. Journal of China Coal Society, 2012, 37(12): 1953–1959. 康红普, 冯彦军. 定向水力压裂工作面煤体应力监测及其演化规律[J]. 煤炭学报, 2012, 37(12): 1953–1959.

[12] MIAO Xiexing. Progress of fully mechanized mining with solid backfilling technology[J]. Journal of China Coal Society, 2012, 37(8): 1247–1255. 缪协兴. 综合机械化固体充填采煤技术研究进展[J]. 煤炭学报, 2012, 37(8): 1247–1255.

[13] ZHANG Jixiong, ZHOU Nan, HUANG Yanli. Impact law of the bulk ratio of backfilling body to overlying strata movement in fully mechanized backfilling mining[J]. Journal of Mining Science, 2011, 47(1): 73–84.

[14] 蔡嗣经, 王洪江. 现代充填理论与技术[M]. 北京: 冶金工业出版社出版, 2012.

[15] SHI Zhijun, Yaoke, YAO Ningping, et al. 40 years of development and prospect on underground coal mine tunnel drilling technology and equipment in China[J]. Coal Science and Technology, 2020, 48(4): 1–34. 石智军, 姚克, 姚宁平, 等. 我国煤矿井下坑道钻探技术装备40年发展与展望[J]. 煤炭科学技术, 2020, 48(4): 1–34.

[16] YANG Junzhe, ZHENG Kaige, WANG Zhenrong, et al. Technology of weakening and danger-breaking dynamic disasters by hard roof[J]. Journal of China Coal Society, 2020, 45(10): 3371–3379. 杨俊哲, 郑凯歌, 王振荣, 等. 坚硬顶板动力灾害超前弱化治理技术[J]. 煤炭学报, 2020, 45(10): 3371–3379.

[17] CHEN Yanguang, QIAN Minggao. Strata control around coal face in China[M]. Xuzhou: Publishing House of China University of Mining and Technology, 1994: 137–143. 陈炎光, 钱鸣高. 中国煤矿采场围岩控制[M]. 徐州: 中国矿业大学出版社, 1994: 137–143.

[18] 钱鸣高, 石平五, 许家林. 矿山压力与岩层控制[M]. 徐州: 中国矿业大学出版社, 2010.

[19] YANG Junzhe, ZHENG Kaige. The mechanism of overburden dynamic disasters and its control technology in top-coal caving in the mining of thick coal seams[J]. Journal of Mining & Safety Engineering, 2020, 37(4): 750–758. 杨俊哲, 郑凯歌. 厚煤层综放开采覆岩动力灾害原理及防治技术[J]. 采矿与安全工程学报, 2020, 37(4): 750–758.