Journal of Central South University

, Volume 25, Issue 2, pp 448–460

# Prediction of upper limit position of bedding separation overlying a coal roadway within an extra-thick coal seam

• Hong Yan (严红)
• Ji-xiong Zhang (张吉雄)
• Lin-yue Li (李林玥)
• Rui-min Feng (冯锐敏)
• Tian-tong Li (李天彤)
Article

## Abstract

Failure of the surrounding rock around a roadway induced by roof separation is one major type of underground roof-fall accidents. This failure can especially be commonly-seen in a bottom-driven roadway within an extra-thick coal seam (“bottom-driven roadway” is used throughout for ease of reference), containing weak partings in their roof coal seams. To determine the upper limit position of the roof interlayer separation is the primary premise for roof control. In this study, a mechanical model for predicting the interlayer separation overlying a bottom-driven roadway within an extra-thick coal seam was established and used to deduce the vertical stress, and length, of the elastic, and plastic zones in the rock strata above the wall of the roadway as well as the formulae for calculating the deflection in different regions of rock strata under bearing stress. Also, an approach was proposed, calculating the stratum load, deflection, and limiting span of the upper limit position of the interlayer separation in a thick coal seam. Based on the key strata control theory and its influence of bedding separation, a set of methods judging the upper limit position of the roof interlayer separation were constructed. In addition, the theoretical prediction and field monitoring for the upper limit position of interlayer separation were conducted in a typical roadway. The results obtained by these two methods are consistent, indicating that the methods proposed are conducive to improving roof control in a thick coal seam.

## Key words

extra-thick coal seam bedding separation coal roadway roof fall mechanical model

# 特厚煤层沿底巷道顶板层间离层上限位置的判定方法

## References

1. [1]
UNAL E, OZKAN I, CAKMAKCI G. Modeling the behaviour of longwall coal mine gate roadways subjected to dynamic loading [J]. International Journal of Rock Mechanics and Mining Sciences, 2001, 38(2): 181–197.
2. [2]
GONG Feng-qiang, LI Xi-bing, GAO Ke. Catastrophe progression method for stability classification of underground engineering surrounding rock [J]. Journal of Central South University: Science and Technology, 2008, 39(5): 1081–1087. (in Chinese)Google Scholar
3. [3]
LIU Hong-tao. Research on the design method of parameters supporting with bolt in coal road on the base of the anchored-clustered structure [D]. Beijing: China University of Mining and Technology (Beijing), 2007. (in Chinese)Google Scholar
4. [4]
JIANG Li-shuai, SAINOKI A, MITRI H S, MA Nian-jie, HAO Zhen. Influence of fracture-induced weakening on coal mine gateroad stability [J]. International Journal of Rock Mechanics and Mining Sciences, 2016, 88: 307–317.
5. [5]
ZHANG Yuan, WAN Zhi-jun, GU Bin, ZHOU Chang-bing. An experimental investigation of transient heat transfer in surrounding rock mass of high geothermal roadway [J]. Thermal Science, 2016, 20(6): 2115–2124.
6. [6]
KUSHWAHA A, SINGH SK, TEWARI S, SINHA A. Empirical approach for designing of support system in mechanized coal pillar mining [J]. International Journal of Rock Mechanics and Mining Sciences, 2010, 47(7): 1063–1078.
7. [7]
PALEI S K, DAS S K. Sensitivity analysis of support safety factor for predicting the effects of contributing parameters on roof falls in underground coal mines [J]. International Journal of Coal Geology, 2008, 75(4): 241–247.
8. [8]
XIE He-ping, WANG Jin-hua, SHEN Bao-hong, LIU Jian-zhong, JIANG Peng-fei, ZHOU Hong-wei, LIU Hong, WU Gang. New idea of coal mining: Scientific mining and sustainable mining capacity [J]. Journal of China Coal Society, 2012, 37(7): 1069–1079.Google Scholar
9. [9]
YAN Hong. Roof coal deformation mechanism and its control technology for roadways driving along the floor in ultra-thick coal seams [M]. Xuzhou: China University of Mining and Technology Press, 2017. (in Chinese)Google Scholar
10. [10]
KUMARA R, SINGHA A K, MISHRAB A K, SINGHA R. Underground mining of thick coal seams [J]. International Journal of Mining Science and Technology, 2015, 25(6): 885–896.
11. [11]
WANG Qi. Research on control mechanism of surrounding rock failure in deep roadways with thick top-coal and contrast of new support systems [D]. Jinan: Shandong University, 2012. (in Chinese)Google Scholar
12. [12]
LI S C, WANG Q, WANG H T, JIANG B, WANG D C, ZHANG B, LI Y, RUAN G Q. Model test study on surrounding rock deformation and failure mechanisms of deep roadways with thick top coal [J]. Tunnelling and Underground Space Technology, 2015, 47: 52–63.
13. [13]
HEBBLEWHITE B K, LU T. Geomechanical behavior of laminated, weak coal mine roof strata and the implications for a ground reinforcement strategy [J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(1): 147–157.
14. [14]
LU Ting-kai, LIU Yu-zhou, YU Hai-yong. Separation characteristics and mechanisms of laminated composite roof strata of longwall roadway [J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(sn1): 4663–4669.(in Chinese)Google Scholar
15. [15]
SHEN Bao-tang, POULSEN B. Investigation of overburden behaviour for grout injection to control mine subsidence [J]. International Journal of Mining Science and Technology, 2014, 24(3): 317–323.
16. [16]
ZHANG Nong, YUAN Liang. Control principle of separating and broken roof rock strata in roadway [J]. Journal of Mining & Safety Engineering, 2006, 23(1): 34–38. (in Chinese)
17. [17]
SHEN Rong-xi, LIU Chang-you, WU Xiu-yi. Analysis and calculation on roof separation critical values of solid-coal roadway and gob-side roadway supported with bolts [J]. Journal of Sichuan University: Engineering Science Edition, 2007, 39(3): 19–23. (in Chinese)Google Scholar
18. [18]
GU Shuan-cheng, DING Xiao. Elastoplastic analysis of effect of bed separation on anchored mass loading in rock mass [J]. Rock and Soil Mechanics, 2013, 34(9): 2649–2654. (in Chinese)Google Scholar
19. [19]
JACOB O. The origin of roof falls in starting faces with the caving system [J]. International Journal of Rock Mechanics and Mining Sciences, 1964, 1(3): 313–314.
20. [20]
ZHANG Guo-hua, LIANG Bing, ZHANG Hong-wei, ZHANG Xue-feng. Analysis of the roof separation in mining roadway and technical parameters determination of bolt combined supporting [J]. Journal of Chongqing University, 2010, 33(7): 135–140. (in Chinese)Google Scholar
21. [21]
HAN Chang-liang, ZHANG Nong, LI Gui-cheng, KAN Jia-guang. Bed separation mechanism under sequential roof collapse condition in a gob-side entry retaining [J]. Journal of China University of Mining & Technology, 2012, 41(6): 893–899. (in Chinese)Google Scholar
22. [22]
YU Tao, WANG Lai-gui. Mechanism of generation of overburden separation layer [J]. Journal of Liaoning Technical University, 2006, 25(1): 132–134. (in Chinese)
23. [23]
APEL D B. Using ground penetrating radar (GPR) in analyzing structural composition of mine roof [J]. Mining Engineering, 2005, 57: 56–60.Google Scholar
24. [24]
XIE Jian-lin, XU Jia-lin. Numerical and physical simulation of the detection of roof separation with ground penetrating radar [J]. Journal of Mining & Safety Engineering, 2017, 34(2): 317–322. (in Chinese)Google Scholar
25. [25]
ZHANG Bai-sheng, KANG Li-xun, YANG Shuang-suo. Numerical simulation on roof separation and deformation of full seam roadway with stratified roof and large section [J]. Journal of Mining & Safety Engineering, 2006, 23(3): 264–267. (in Chinese)Google Scholar
26. [26]
QIAN Ping-gao, XIE He-ping. Stability analysis of the damage rock strata within the roof and floor of the roadway [J]. Jiangsu Coal, 1992, 12(3): 12–15. (in Chinese)Google Scholar
27. [27]
WU De-yi, WEN Guang-kun, WANG Ai-lan. Discrimination of stability between layers of compound roof in deep mining [J]. Journal of Mining & Safety Engineering, 2011, 28(2): 252–257. (in Chinese)Google Scholar
28. [28]
KWON S, WILSON J W. Deformation mechanism of the underground excavations at the WIPP site [J]. Rock Mechanics and Rock Engineering, 1999, 32(2): 101–122.
29. [29]
QIAN Ming-gao, MIAO Xie-xing, XU Jia-lin. Key strata theory in ground control [M]. Xuzhou: China University of Mining and Technology Press, 2003. (in Chinese)Google Scholar

© Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2018

## Authors and Affiliations

• Hong Yan (严红)
• 1
• Ji-xiong Zhang (张吉雄)
• 1
• Lin-yue Li (李林玥)
• 2
• Rui-min Feng (冯锐敏)
• 3
• Tian-tong Li (李天彤)
• 1
1. 1.State Key Laboratory of Coal Resource and Safe MiningKey Laboratory of Deep Coal Resource Mining of Ministry of Education of China (China University of Mining & Technology)XuzhouChina
2. 2.Guizhou Xinlian Blasting Engineering Group Co., LtdGuiyangChina
3. 3.Department of Chemical and Petroleum EngineeringUniversity of CalgaryCalgaryCanada