Evolution of the Overlying-Strata-Bearing Structure and the Permeability Distribution of the Broken Interlayer in Shallow Multiseam Mining
Publication: International Journal of Geomechanics
Volume 23, Issue 8
Abstract
Due to the particularity of the occurrence characteristics of shallow multiseam mining, underground mining space is vulnerable to obvious roof behaviors and serious gas anomalies, which are closely related to the destruction and migration characteristics of the overlying strata, the characteristics of the overlying-strata-bearing structure, and the permeability distribution of the broken interlayer under the influence of the overlying-strata-bearing structure. However, the related research is still insufficient. In this work, the discrete-element method (DEM) numerical model was used to simulate the entire process of the continuous mining of a shallow multiseam. In addition, the gas migration and its distribution in the lower mining field, under the influence of low-oxygen (O2) gas intrusion into the upper goaf, and the air leakage flow in the working face were studied using a Particle-Flow Code (PFC)–COMSOL coupling method. The results showed that the main feature in the evolution of the overlying-strata-bearing structure was the dynamic change in the supporting relationship between the collapse area and the surrounding rock, which changed from complete support to local force conduction, and finally complete separation under continuous mining in the upper and lower coal seams. The load distribution of the coal-seam floor presented a continuous change from surrounding rock to inside the goaf, with the breaking angle of the overlying strata being the key influencing factor. The conjoint analysis of stress and porosity indicated that the load under the overlying-strata-bearing structure determined the permeability distribution of the broken interlayer, which gave the gas in the goaf obvious distribution characteristics.
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Acknowledgments
The authors are grateful for the financial support from the National Natural Science Foundation of China (52130409, 52121003, 52004291) and the Fundamental Research Funds for the Central Universities (2022YJSAQ03, 2022XJAQ02).
References
Adhikary, D., M. Khanal, C. Jayasundara, and R. Balusu. 2016. “Deficiencies in 2D simulation: A comparative study of 2D versus 3D simulation of multi-seam longwall mining.” Rock Mech. Rock Eng. 49 (6): 2181–2185. https://doi.org/10.1007/s00603-015-0842-7.
Cheng, G., T. Yang, H. Liu, L. Wei, Y. Zhao, Y. Liu, and J. Qian. 2020. “Characteristics of stratum movement induced by downward longwall mining activities in middle-distance multi-seam.” Int. J. Rock Mech. Min. Sci. 136: 104517. https://doi.org/10.1016/j.ijrmms.2020.104517.
Ding, X., and L. Zhang. 2014. “A new contact model to improve the simulated ratio of unconfined compressive strength to tensile strength in bonded particle models.” Int. J. Rock Mech. Min. Sci. 69: 111–119. https://doi.org/10.1016/j.ijrmms.2014.03.008.
Fan, X., K. Li, H. Lai, Y. Xie, R. Cao, and J. Zheng. 2018. “Internal stress distribution and cracking around flaws and openings of rock block under uniaxial compression: A particle mechanics approach.” Comput. Geotech. 102: 28–38. https://doi.org/10.1016/j.compgeo.2018.06.002.
Feng, G., and P. Wang. 2020. “Stress environment of entry driven along gob-side through numerical simulation incorporating the angle of break.” Int. J. Min. Sci. Technol. 30 (2): 189–196. https://doi.org/10.1016/j.ijmst.2019.03.003.
Ghabraie, B., K. Ghabraie, G. Ren, and J. V. Smith. 2017. “Numerical modelling of multistage caving processes: Insights from multi-seam longwall mining-induced subsidence.” Int. J. Numer. Anal. Methods Geomech. 41 (7): 959–975. https://doi.org/10.1002/nag.2659.
Ghabraie, B., and G. Ren. 2016. “Mechanism and prediction of ground surface subsidence due to multiple-seam longwall mining.” In Proc., 35th Int. Conf., on Ground Control in Mining. Morgantown, WV: University of West Virginia.
Ghabraie, B., G. Ren, and J. V. Smith. 2017a. “Characterising the multi-seam subsidence due to varying mining configuration, insights from physical modelling.” Int. J. Rock Mech. Min. Sci. 93: 269–279. https://doi.org/10.1016/j.ijrmms.2017.02.001.
Ghabraie, B., G. Ren, J. Barbato, and J. V. Smith. 2017b. “A predictive methodology for multi-seam mining induced subsidence.” Int. J. Rock Mech. Min. Sci. 93: 280–294. https://doi.org/10.1016/j.ijrmms.2017.02.003.
Huang, Q. X. 1998. “Study on roof control in shallow seam longwall mining.” Chin. J. Rock Mech. Eng. 17 (5): 521–526.
Huang, Q., J. Du, J. Chen, and Y. He. 2021. “Coupling control on pillar stress concentration and surface cracks in shallow multi-seam mining.” Int. J. Min. Sci. Technol. 31 (1): 95–101. https://doi.org/10.1016/j.ijmst.2020.12.019.
Huang, Q. X., M. G. Qian, and P. W. Shi. 1999. “Structural analysis of main roof stability during periodic weighting in longwall face.” J. Chin. Coal Soc. 24 (6): 581–585.
Itasca Consulting Group. 2018. PFC-particle flow code in 2 dimensions, version 5.0 [user’s manual]. Minneapolis: Itasca Consulting Group.
Ju, J., and J. Xu. 2015a. “Surface stepped subsidence related to top-coal caving longwall mining of extremely thick coal seam under shallow cover.” Int. J. Rock Mech. Min. Sci. 78: 27–35. https://doi.org/10.1016/j.ijrmms.2015.05.003.
Ju, J., J. Xu, and W. Zhu. 2015b. “Longwall chock sudden closure incident below coal pillar of adjacent upper mined coal seam under shallow cover in the Shendong coalfield.” Int. J. Rock Mech. Min. Sci. 77: 192–201. https://doi.org/10.1016/j.ijrmms.2015.04.004.
Juncal, A. S., D. M. Ivars, A. Brzovic, and J. Vallejos. 2014. “Simulating the effect of preconditioning in primary fragmentation.” In Proc., Int. Soc. for Rock Mechanics Regional Symp. EUROCK 2014, 661–665. Vigo 27-29. Lisbon, Portugal: International Society for Rock Mechanics (ISRM).
Kang, P., L. Zhaopeng, Z. Quanle, Z. Zhenyu, and Z. Jiaqi. 2019. “Static and dynamic mechanical properties of granite from various burial depths.” Rock Mech. Rock Eng. 52 (10): 3545–3566. https://doi.org/10.1007/s00603-019-01810-y.
Li, B., Y. Liang, L. Zhang, and Q. Zou. 2019. “Experimental investigation on compaction characteristics and permeability evolution of broken coal.” Int. J. Rock Mech. Min. Sci. 118: 63–76. https://doi.org/10.1016/j.ijrmms.2019.04.001.
Lu, M., X. Sun, Y. Xiao, and C. Zhang. 2022. “The development mining-induced surface cracks in shallow coal seam through double-gully terrain: A case study in a coal mine.” Bull. Eng. Geol. Environ. 81 (9): 1–14. https://doi.org/10.1007/s10064-022-02882-x.
Qin, Y., N. Xu, Z. Zhang, and B. Zhang. 2021. “Failure process of rock strata due to multi-seam coal mining: Insights from physical modelling.” Rock Mech. Rock Eng. 54 (5): 2219–2232. https://doi.org/10.1007/s00603-021-02415-0.
Shen, Z., M. Jiang, and C. Thornton. 2016. “DEM simulation of bonded granular material. Part I: Contact model and application to cemented sand.” Comput. Geotech. 75: 192–209. https://doi.org/10.1016/j.compgeo.2016.02.007.
Shu, L., K. Wang, Z. Liu, W. Zhao, N. Zhu, and Y. Lei. 2022. “A novel physical model of coal and gas outbursts mechanism: Insights into the process and initiation criterion of outbursts.” Fuel 323: 124305. https://doi.org/10.1016/j.fuel.2022.124305.
Sun, Y., J. Zuo, M. Karakus, and J. Wang. 2019. “Investigation of movement and damage of integral overburden during shallow coal seam mining.” Int. J. Rock Mech. Min. Sci. 117: 63–75. https://doi.org/10.1016/j.ijrmms.2019.03.019.
Tulu, I. B., G. S. Esterhuizen, T. Klemetti, M. M. Murphy, J. Sumner, and M. Sloan. 2016. “A case study of multi-seam coal mine entry stability analysis with strength reduction method.” Int. J. Min. Sci. Technol. 26 (2): 193–198. https://doi.org/10.1016/j.ijmst.2015.12.003.
Wang, C., X. Li, L. Liu, Z. Tang, and C. Xu. 2023. “Dynamic effect of gas initial desorption in coals with different moisture contents and energy-controlling mechanism for outburst prevention of water injection in coal seams.” J. Pet. Sci. Eng. 220: 111270. https://doi.org/10.1016/j.petrol.2022.111270.
Wang, C., C. Zhang, X. Zhao, L. Liao, and S. Zhang. 2018. “Dynamic structural evolution of overlying strata during shallow coal seam longwall mining.” Int. J. Rock Mech. Min. Sci. 103: 20–32. https://doi.org/10.1016/j.ijrmms.2018.01.014.
Wang, F., C. Du, S. Tu, N. Liang, and Q. Bai. 2017a. “Hydraulic support crushed mechanism for the shallow seam mining face under the roadway pillars of room mining goaf.” Int. J. Min. Sci. Technol. 27 (5): 853–860. https://doi.org/10.1016/j.ijmst.2017.07.013.
Wang, G., M. Wu, R. Wang, H. Xu, and X. Song. 2017b. “Height of the mining-induced fractured zone above a coal face.” Eng. Geol. 216: 140–152. https://doi.org/10.1016/j.enggeo.2016.11.024.
Wang, J., J. Zhang, and Z. Li. 2016. “A new research system for caving mechanism analysis and its application to sublevel top-coal caving mining.” Int. J. Rock Mech. Min. Sci. 88: 273–285. https://doi.org/10.1016/j.ijrmms.2016.07.032.
Wang, K., and F. Du. 2020. “Coal-gas compound dynamic disasters in China: A review.” Process Saf. Environ. Prot. 133: 1–17. https://doi.org/10.1016/j.psep.2019.10.006.
Wei, J., S. Wang, S. Song, Q. Sun, and T. Yang. 2022. “Experiment and numerical simulation of overburden and surface damage law in shallow coal seam mining under the gully.” Bull. Eng. Geol. Environ. 81 (5): 1–17. https://doi.org/10.1007/s10064-022-02706-y.
Xu, C., G. Yang, K. Wang, and Q. Fu. 2021. “Uneven stress and permeability variation of mining-disturbed coal seam for targeted CBM drainage: A case study in Baode coal mine, eastern Ordos Basin, China.” Fuel 289: 119911. https://doi.org/10.1016/j.fuel.2020.119911.
Yang, X., G. Wen, L. Dai, H. Sun, and X. Li. 2019. “Ground subsidence and surface evolution from shallow-buried close-distance multi-seam mining: A case study in Bulianta coal mine.” Rock Mech. Rock Eng. 52 (8): 2835–2852. https://doi.org/10.1007/s00603-018-1726-4.
Yang, X., P. H. S. W. Kulatilake, H. Jing, and S. Yang. 2015. “Numerical simulation of a jointed rock block mechanical behavior adjacent to an underground excavation and comparison with physical model test results.” Tunnelling Underground Space Technol. 50: 129–142. https://doi.org/10.1016/j.tust.2015.07.006.
Yu, B. 2015. “Structural evolution of breaking roof group of multiple coal seams and its influence on lower coal seam mining.” J. Chin. Coal Soc. 40 (2): 261–266.
Yuan, L. 2016. “Control of coal and gas outbursts in Huainan mines in China: A review.” J. Rock Mech. Geotech. Eng. 8 (4): 559–567. https://doi.org/10.1016/j.jrmge.2016.01.005.
Zou, Q., and B. Lin. 2018. “Fluid–solid coupling characteristics of gas-bearing coal subjected to hydraulic slotting: An experimental investigation.” Energy Fuels 32: 1047–1060. https://doi.org/10.1021/acs.energyfuels.7b02358.
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Published In
International Journal of Geomechanics
Volume 23 • Issue 8 • August 2023
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Sep 24, 2022
Accepted: Feb 24, 2023
Published online: May 17, 2023
Published in print: Aug 1, 2023
Discussion open until: Oct 17, 2023
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