Abstract
A multi-layer gangue roof of a steeply dipping coal seam with a large mining height face area was analyzed using physical simulation, numerical simulation, theoretical analysis, and field measurement methods to evaluate the roof deformation and the mechanisms associated with the instability of the hard gangue and soft coal interlayer. The results indicated that the first weighting step of the multi-gangue roof was larger than that of a non-gangue roof, but periodic weighting steps were similar. The overburden collapse height was lower in the multi-gangue roof than in the non-gangue roof due to the buffering and supporting function of the collapsed gangue. Moreover, the failure of the coal interlayer was the key factor in the collapse of the multi-layer gangue. A mechanical model was established for the hard gangue and soft coal interlayer based on a revised Prandtl squeezing theory. The limited load of the interlayer and maximum resistance of the shield support was thus modeled. The maximum resistance of the support increased with the dip angle of the seam and burial depth. It also increased with the interlayer thickness at thicknesses below 2.75 m. It reached a peak when the interlayer thickness was between 2.75 and 3 m and exhibited a decreasing trend when the thickness was greater than 3 m. The results were confirmed using physical simulation and a field test. Certain measures were proposed to control the stability of the gangue roof, including zoning control of the mining height and resistance and advancing the support while maintaining roof contact, thus ensuring the integrity of the support and surrounding rock system.
Similar content being viewed by others
References
Yongping W, Kongzhi L, Dongfeng Y, Panshi X, Hongwei W (2014) Research progress on the safe and efficient mining technology of steeply dipping seam. J China Coal Soc 39(8):1611–1618
Jinhua W (2006) Present status and development tendency of fully mechanized coal mining technology and equipment with high cutting height in China. Coal Sci Technol 34(1):4–7
Peilin G, Zhongming J (2004) Study on the structure characteristics and movement laws of overlying strata with large mining height. J China Coal Soc 29(1):7–11
Panshi X, Yongping W, Hongwei W, Shiguang R (2015) Interaction characteristics between strata movement and support system around large mining height fully-mechanized face in steeply inclined seam. J Min Saf Eng 32(1):14–19
Wang G, Pang Y (2017) Surrounding rock control theory and longwall mining technology innovation. Int J Coal Sci Technol 4(4):301–309
Yongping W, Yongqiang W, Panshi X, Hongwei W, Wenyu L (2018) Similar simulation on movement behavior of overlying strata in working face with large dip angle and large mining height under the roof of interbedded coal gangue. Coal Eng 50(1):73–76,80
Xue J, Wang H, Zhou W, Ren B, Duan C, Deng D (2015) Experimental research on overlying strata movement and fracture evolution in pillarless stress-relief mining. Int J Coal Sci Technol 2(1):38–45
Xie P, Wu Y (2019) Deformation and failure mechanisms and support structure technologies for gob-side entries in steep-seam group considering multiple mining disturbances. Arch Min Sci 64(3):561–574
Wu YP, Hu BS, Xie PS (2019) A new experimental system for quantifying the multidimensional loads on an on-site hydraulic support in steeply dipping seam mining. Exp Tech 43:571–585
Jiachen W, Jinwang Z, Shengli Y, Zhengyanh S (2015) 3-D movement law of top-coal in near horizontal coal seam with multi-gangue under caving mining technique. J China Coal Soc 40(5):979–987
Zhang D, Wang Y (2000) Analysis of failure characteristic of top-coal with rock parting. J Chin Univ Min Technol 29(2):160–163
Jiachen W, Yinchao Y, Dezhong K, Weidong P (2014) Failure mechanism and grouting reinforcement technique of large mining height coal wall in thick coal seam with gangue during topple mining. J Min Saf Eng 31(6):831–837
Jingxuan Y, Changyou L, Fengfeng W, Yu Y (2013) The research on the coal wall stability mechanism in larger height coal seam with a stratum of gangue. J Min Saf Eng 30(6):856–862
Guodong L (2012) Mining technology and process practice of inclined longwall under the condition of composite roof and coal gangue interlayer [A]. Scientific and technical papers on the innovative development of technology theory and practice of fully mechanized coal caving mining 30 years [C]. 6
Yong Y, Guo-qing Z (2015) Ultimate load analysis of soft interlayer. Rock Soil Mech 36(4):1035–1040
Fangli L, Yongping W, Jianjie C, et al. (2013) Research on fully mechanized technology by using large mining height method along longwall mining face in steeply dipping seam [R]. Wulumuqi: Xinjiang Tar Coal Group Co. Ltd, Xi’an: Xi’an University of Science and Technology, (in Chinese)
Ning W (2015) Research on mechanism and prevention of coal bumps under the condition of hard coal-rock structure [D]. China University of Mining & Technology, Beijing
Yuanwei S (1999) Mutual function between hydraulic powered support and surrounding rock mechanism and study on election of hydraulic support. Coal Sci Technol 05(30–35):4
Acknowledgments
The authors acknowledge and appreciate the technical support provided by Coal Mine No. 2130 of Xinjiang Coking Coal (Group) Co., Ltd.
Funding
This work was supported by the National Natural Science Foundation of China (grant numbers: 51774230, 51634007, and 51604212) and Peak Project of Mining Engineering (grant number: 2018GG-2-07).
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of Interest
The authors declare that they have no conflict of interest.
Additional information
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Xie, P., Zhang, Y., Luo, S. et al. Instability Mechanism of a Multi-Layer Gangue Roof and Determination of Support Resistance Under Inclination and Gravity. Mining, Metallurgy & Exploration 37, 1487–1498 (2020). https://doi.org/10.1007/s42461-020-00252-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s42461-020-00252-3