Deep beam theory-based mechanical analysis of water-resisting key strata of coal seam floors in a deep mining environment

Authors

WANG Bingwen, School of Civil & Architecture Engineering, East China University of Technology, Nanchang 330013, ChinaFollow
ZHA Wenhua, School of Civil & Architecture Engineering, East China University of Technology, Nanchang 330013, China
LU Haifeng, School of Earth and Environment, Anhui University of Science & Technology, Huainan 232001, China

Abstract

Objective An increase in the mining depth of mines poses a more serious threat from highly confined karst water, resulting in water hazards like water inflow and inrushes on the mining faces of coal seams. The key content used to address this issue is to analyze the water pressure resistance of the water-resisting key stratum of the coal seam floor in a deep mining environment. Methods This study simplified a water-resisting key stratum into a rock beam model and then dealt with this model using the deep beam theory in the prediction of water inrushes in deep mining. Specifically, by combining theoretical analysis with numerical simulation, this study sliced the deep beam into shallow beams based on the bending mechanical characteristics of the deep beam and previous research results. Then, according to the elastic force distribution of various shallow beams, it was assumed that the interlayer compressive stress σ_y was a cubic function and presented a slicing technique to determine the bending stress of the deep beam. Finally, the calculated results were compared with the elastic mechanic solutions and the FLAC^3D simulation results. Results and Conclusions The results indicate that the stress and displacement obtained through the slicing of the deep beam were closer to the numerical simulation results, yielding more accurate calculation results with relative error less than 10%. As the number of shallow beams increased, more accurate calculation results were obtained. However, the increased amplitude of the accuracy gradually decreased, necessitating appropriate slicing of the deep rock beam model in engineering applications. Furthermore, errors increased with the height/span length (h/l) ratio. Therefore, appropriate slicing widths are required, otherwise errors will increase. An example of a water-resisting key stratum of a coal seam floor demonstrates that a h/l ratio exceeding 0.2 suggests a typical deep beam. In this case, the maximum tensile stress calculated using conventional elastic mechanics exhibited relative error reaching up to 40.6%, exerting a negative impact on properly determining the risks of water inrushes in the water-resisting key stratum. In contrast, the deep-beam slicing method manifested higher accuracy in solving stress, thus serving as a significant guide for the prediction of water inrushes from deep coal seam floors.

Keywords

deep mining, floor aquiclude, rock beam model, deep beam, numerical simulation, water inrush prediction

DOI

10.12363/issn.1001-1986.23.12.0869

Recommended Citation

WANG Bingwen, ZHA Wenhua, LU Haifeng, et al. (2024) "Deep beam theory-based mechanical analysis of water-resisting key strata of coal seam floors in a deep mining environment," Coal Geology & Exploration: Vol. 52: Iss. 9, Article 9.
DOI: 10.12363/issn.1001-1986.23.12.0869
Available at: https://cge.researchcommons.org/journal/vol52/iss9/9

Reference

[1] 袁亮. 我国煤炭主体能源安全高质量发展的理论技术思考[J]. 中国科学院院刊，2023，38(1)：11−22.

YUAN Liang. Theory and technology considerations on high-quality development of coal main energy security in China[J]. Bulletin of Chinese Academy of Sciences，2023，38(1)：11−22.

[2] 孙文洁，李文杰，宁殿艳，等. 我国煤矿水害事故现状、预测及防治建议[J]. 煤田地质与勘探，2023，51(12)：185−194.

SUN Wenjie，LI Wenjie，NING Dianyan，et al. Current states，prediction and prevention suggestions for water hazard accidents in China’s coal mines[J]. Coal Geology & Exploration，2023，51(12)：185−194.

[3] 何满潮，谢和平，彭苏萍，等. 深部开采岩体力学研究[J]. 岩石力学与工程学报，2005，24(16)：2803−2813.

HE Manchao，XIE Heping，PENG Suping，et al. Study on rock mechanics in deep mining engineering[J]. Chinese Journal of Rock Mechanics and Engineering，2005，24(16)：2803−2813.

[4] 谢和平. “深部岩体力学与开采理论” 研究构想与预期成果展望[J]. 工程科学与技术，2017，49(2)：1−16.

XIE Heping. Research framework and anticipated results of deep rock mechanics and mining theory[J]. Advanced Engineering Sciences，2017，49(2)：1−16.

[5] 李强. 煤层底板隔水关键层失稳及突水危险性研究[D]. 青岛：山东科技大学，2019.

LI Qiang. Study on coal seam floor water resisting key strata instability and water inrush risk[D]. Qingdao：Shandong University of Science and Technology，2019.

[6] 郑士田，马荷雯，姬亚东. 煤层底板水害区域超前治理技术优化及其应用[J]. 煤田地质与勘探，2021，49(5)：167−173.

ZHENG Shitian，MA Hewen，JI Yadong. Optimization of regional advanced coal floor water hazard prevention and control technology and its application[J]. Coal Geology & Exploration，2021，49(5)：167−173.

[7] 王素玲，娄富林. 深部煤层开采数值模拟与底板突水预测[J]. 煤炭技术，2020，39(5)：122−125.

WANG Suling，LOU Fulin. Numerical simulation of deep coal seam mining and prediction of water inrush from floor[J]. Coal Technology，2020，39(5)：122−125.

[8] 尹尚先，王屹，尹慧超，等. 深部底板奥灰薄灰突水机理及全时空防治技术[J]. 煤炭学报，2020，45(5)：1855−1864.

YIN Shangxian，WANG Yi，YIN Huichao，et al. Mechanism and full-time-space prevention and control technology of water inrush from Ordovician and thin limestone in deep mines[J]. Journal of China Coal Society，2020，45(5)：1855−1864.

[9] 范胜洋. 采动底板突水孕灾演化规律研究[D]. 徐州：中国矿业大学，2020.

FAN Shengyang. Study on the evolution law of water inrush from mining floor[D]. Xuzhou：China University of Mining and Technology，2020.

[10] 钱鸣高，缪协兴，许家林，等. 岩层控制的关键层理论[M]. 徐州：中国矿业大学出版社，2000：199–218.

[11] 孙建，王连国，鲁海峰. 基于隔水关键层理论的倾斜煤层底板突水危险区域分析[J]. 采矿与安全工程学报，2017，34(4)：655−662.

SUN Jian，WANG Lianguo，LU Haifeng. The analysis of the water-inrush dangerous areas in the inclined coal seam floor based on the theory of water-resisting key strata[J]. Journal of Mining & Safety Engineering，2017，34(4)：655−662.

[12] 鲁海峰，孟祥帅，张元，等. 采场底板层状结构关键层隔水性能力学分析[J]. 中国矿业大学学报，2020，49(6)：1057−1066.

LU Haifeng，MENG Xiangshuai，ZHANG Yuan，et al. Mechanical analysis of water barrier performance of floor layered structure key stratum on coal face[J]. Journal of China University of Mining & Technology，2020，49(6)：1057−1066.

[13] 冯梅梅，茅献彪，朱庆华. 底板隔水层岩性组合特征对隔水性能的影响[J]. 采矿与安全工程学报，2010，27(3)：404−409.

FENG Meimei，MAO Xianbiao，ZHU Qinghua. Effect of lithologic association of the water-resisting strata in coal seam floor on water insulating[J]. Journal of Mining & Safety Engineering，2010，27(3)：404−409.

[14] 孙强，刘恒凤，张吉雄，等. 充填开采隔水关键层渗流稳定性力学模型及分析[J]. 采矿与安全工程学报，2022，39(2)：273−281.

SUN Qiang，LIU Hengfeng，ZHANG Jixiong，et al. Mechanical model and analysis of seepage stability in key aquiclude strata during backfill mining[J]. Journal of Mining & Safety Engineering，2022，39(2)：273−281.

[15] 阮浩. 基于欧拉梁理论的风电叶片疲劳试验弯矩匹配优化方法研究[D]. 重庆：重庆理工大学，2023.

RUAN Hao. Research on optimization method of bending moment matching in fatigue test of wind turbine blades based on Euler beam theory[D]. Chongqing：Chongqing University of Technology，2023.

[16] 谢丹，黄勇刚. 大挠度欧拉梁三参数曲率模型及其在平面柔顺机构中的应用[J]. 机械工程学报，2021，57(13)：144−152.

XIE Dan，HUANG Yonggang. Novel model with three curvature variables for Euler beam under large deflection and its application in planar compliant mechanisms[J]. Journal of Mechanical Engineering，2021，57(13)：144−152.

[17] 祝卫亮，葛耀君. 悬索桥桁架加劲梁动力等效成等截面欧拉梁方法[J]. 哈尔滨工业大学学报，2020，52(9)：17−24.

ZHU Weiliang，GE Yaojun. Simplified method for dynamic equivalent Euler beam of truss girder in suspension bridge[J]. Journal of Harbin Institute of Technology，2020，52(9)：17−24.

[18] 余阳，杨洋. 基于非局部应变梯度欧拉梁模型的充流单壁碳纳米管波动分析[J]. 振动与冲击，2017，36(8)：1−8.

YU Yang，YANG Yang. Wave propagation of fluid-filled single-walled carbon nanotubes based on the nonlocal-strain gradient theory[J]. Journal of Vibration and Shock，2017，36(8)：1−8.

[19] 夏桂云，曾庆元. 深梁理论的研究现状与工程应用[J]. 力学与实践，2015，37(3)：302−316.

XIA Guiyun，ZENG Qingyuan. Timoshenko beam theory and its applications[J]. Mechanics in Engineering，2015，37(3)：302−316.

[20] TIMOSHENKO S P. LXVI. On the correction for shear of the differential equation for transverse vibrations of prismatic bars[J]. The Philosophical Magazine：A Journal of Theoretical Experimental and Applied Physics，1921，41(245)：744−746.

[21] 王妍，姚多喜，鲁海峰. 高水压作用下煤层底板隔水关键层弹性力学解[J]. 煤田地质与勘探，2019，47(1)：127−132.

WANG Yan，YAO Duoxi，LU Haifeng. Elastic mechanics solution of water proof key layer in coal seam floor under high water pressure[J]. Coal Geology & Exploration，2019，47(1)：127−132.

[22] 李博，刘子捷. 煤层底板富水承压溶洞突水力学模型构建及突水判据研究[J]. 煤炭科学技术，2022，50(5)：232−237.

LI Bo，LIU Zijie. Construction of mechanical model of water inrush from water-rich confined karst cave in coal seam floor and study on criterion[J]. Coal Science and Technology，2022，50(5)：232−237.

[23] 刘泽威，刘其声，刘洋. 煤层底板隐伏断层分类及突水防治措施[J]. 煤田地质与勘探，2020，48(2)：141−146.

LIU Zewei，LIU Qisheng，LIU Yang. Classification of hidden faults in coal seam floor and measures for water inrush prevention[J]. Coal Geology & Exploration，2020，48(2)：141−146.

[24] HUANG Pinghua，HU Yongsheng，GAO Hongfei，et al. Dynamic identification and radium–radon response mechanism of floor mixed water source in high ground temperature coal mine[J]. Journal of Hydrology，2021，603(part B)：126942.

[25] SUN Ming，GUO Chen，ZHENG Wenxiang，et al. Study on broken floor rock mass by mining underground pressure[J]. Mathematical Problems in Engineering，2021，2021：3797188.

[26] LI Qiang，MENG Xiangxi，LIU Yuben. Sensitivity analysis of water inrush evaluation model based on the theory of water resistant key strata：A case study in a coal mine，China[J]. Earth Science Informatics，2022，15(4)：2481−2494.

[27] 段建华. 煤层底板突水综合监测技术及其应用[J]. 煤田地质与勘探，2020，48(4)：19−28.

DUAN Jianhua. Integrated monitoring technology of water inrush from coal seam floor and its application[J]. Coal Geology & Exploration，2020，48(4)：19−28.

[28] 虎维岳，赵春虎，吕汉江. 煤层底板水害区域注浆治理影响因素分析与高效布孔方式[J]. 煤田地质与勘探，2022，50(11)：134−143.

HU Weiyue，ZHAO Chunhu，LYU Hanjiang. Main influencing factors for regional pre-grouting technology of water hazard treatment in coal seam floor and efficient hole arrangement[J]. Coal Geology & Exploration，2022，50(11)：134−143.

[29] 马凯，尹立明，陈军涛，等. 深部开采底板隔水关键层受局部高承压水作用破坏理论分析[J]. 岩土力学，2018，39(9)：3213−3222.

MA Kai，YIN Liming，CHEN Juntao，et al. Theoretical analysis on failure of water-resisting key strata in the floor by local high confined water in deep mining[J]. Rock and Soil Mechanics，2018，39(9)：3213−3222.

[30] 马凯. 受局部高承压水与多含水层影响的深部底板突水危险性理论分析与验证[D]. 青岛：山东科技大学，2019.

MA Kai. Theoretical analysis and verification of water inrush danger in deep mining affected by local high confined water and multiple aquifers[D]. Qingdao：Shandong University of Science and Technology，2019.

[31] 姚明豪. 新桥煤矿底板隔水层结构特征与阻隔水能力研究[D]. 徐州：中国矿业大学，2019.

YAO Minghao. Study on structural characteristics of the floor aquifuge and water-resisting ability of Xinqiao coalmine[D]. Xuzhou：China University of Mining and Technology，2019.

[32] 张建民，李全生，张勇，等. 煤炭深部开采界定及采动响应分析[J]. 煤炭学报，2019，44(5)：1314−1325.

ZHANG Jianmin，LI Quansheng，ZHANG Yong，et al. Definition of deep coal mining and response analysis[J]. Journal of China Coal Society，2019，44(5)：1314−1325.

[33] 朱庆伟，李航，杨小虎，等. 采动覆岩结构演化特征及对地表沉陷的影响分析[J]. 煤炭学报，2019，44(增刊1)：9−17.

ZHU Qingwei，LI Hang，YANG Xiaohu，et al. Influence analysis of between subsidence and structure evolution in overburden rock under mining[J]. Journal of China Coal Society，2019，44(Sup.1)：9−17.

[34] 吴家龙. 弹性力学[M]. 3版. 北京：高等教育出版社，2016.

[35] 刘亮，胡玉茹，张元海. 用材料力学公式计算任意截面短梁正应力时的修正项研究[J]. 计算力学学报，2015，32(3)：383−387.

LIU Liang，HU Yuru，ZHANG Yuanhai. Study on modification term for normal stress of short beam with arbitrary cross section by applying formula in material mechanics[J]. Chinese Journal of Computational Mechanics，2015，32(3)：383−387.

[36] 徐芝纶. 弹性力学-下册[M]. 5版. 北京：高等教育出版社，2016.

[37] 高荣誉，范家让. 叠层深梁的精确解[J]. 合肥工业大学学报(自然科学版)，2009，32(5)：738−741.

GAO Rongyu，FAN Jiarang. An exact solution of deep laminated beams[J]. Journal of Hefei University of Technology (Natural Science)，2009，32(5)：738−741.

[38] 丁大钧，刘伟庆. 深梁杆件力学解[J]. 工程力学，1993，10(1)：10−18.

DING Dajun，LIU Weiqing. Solution of deep beams based on mechanics of bar system[J]. Engineering Mechanics，1993，10(1)：10−18.

[39] 陈林之，李章政. 均布荷载作用下连续深梁问题的级数解答[J]. 机械，2005，32(9)：30−32.

CHEN Linzhi，LI Zhangzheng. Series solution for continuous deep beam subjected to uniform loads[J]. Machinery，2005，32(9)：30−32.

[40] 刘鸿文. 材料力学(第五版)[M]. 北京：高等教育出版社，2014.

[41] QIAN Minggao，MIAO Xiexing，Ll Liangjie. Mechanical behaviour of main floor for water inrush in longwall mining[J]. Journal of China University of Mining and Technology，1995(1)：9−16.