Numerical Estimation of Suitable Gob-Side Filling Wall Width in a Highly Gassy Longwall Mining Panel
Publication: International Journal of Geomechanics
Volume 18, Issue 8
Abstract
Determining a suitable width of gob-side filling wall (GFW) is a major concern in the application of gob-side entry retaining (GER) technology in highly gassy coal mines. This paper presents a workflow for GFW width design based on a rigorous numerical modeling analysis. A meticulously validated numerical model was built to analyze the vertical stress, entry convergence, and plastic zone distribution across the GFW with various sizes. In order to ensure the reliability of the numerical model, a strain-softening model for GFW modeling and a double-yield model for gob modeling were implemented, and the relevant input parameters’ calibration was clearly illustrated. The results demonstrated that when the GFW’s width is 2.5 m, it possesses sufficient load-bearing capacity, and the entry convergence variation tends to stabilize. Consequently, the rational GFW width was estimated as 2.5 m. The field monitoring results demonstrate that a gob-side entry, with a 2.5-m-wide GFW, meets the cross section requirement for gas drainage. The proposed design workflow and modeling procedure can potentially be applied to other GER design under similar geological conditions.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This study was supported by the Foundation of Shandong University of Science and Technology for Recruited Talents (2017RCJJ011), Shandong Provincial First-Class Discipline Foundation (01CK03203 and 02CK02302).
References
Brady, B. H. G., and E. T. Brown. 2004. Rock mechanics: For underground mining. New York: Springer Science and Business Media.
Cai, M., P. K. Kaiser, H. Uno, Y. Tasaka, and M. Minami. 2004. “Estimation of rock mass deformation modulus and strength of jointed hard rock masses using the GSI system.” Int. J. Rock Mech. Min. Sci. 41 (1): 3–19. https://doi.org/10.1016/S1365-1609(03)00025-X.
Chen, Y. 2012. “Study on stability mechanism of rockmass structure movement and its control in gob-side entry retaining.” [In Chinese.] Xuzhou, China: China Univ. of Mining and Technology.
Cheng, Y. M., J. A. Wang, G. X. Xie, and W. B. Wei. 2010. “Three-dimensional analysis of coal barrier pillars in tailgate area adjacent to the fully mechanized top caving mining face.” Int. J. Rock Mech. Min. Sci. 47 (8): 1372–1383. https://doi.org/10.1016/j.ijrmms.2010.08.008.
Feng, X. W., N. Zhang, F. He, S. Yang, and X. Zheng. 2017. “Implementation of a pretensioned, fully bonded bolting system and its failure mechanism based on acoustic emission: A laboratorial and field study.” Geotechnical Testing Journal. 40 (6): 978–999.
He, P.-F., P. H. S. W. Kulatilake, D.-Q. Liu, and M.-C. He. 2016. “Development of new three-dimensional coal mass strength criterion.” Int. J. Geomech. 17 (3): 04016067. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000741.
Hoek, E., C. Carranza-Torres, and B. Corkum, 2002. “Hoek-Brown failure criterion—2002 edition.” In Vol. 1 of Proc. of NARMS-Tac, 267–273. Toronto: University of Toronto Press.
Hyett, A. J., W. F. Bawden, and A. L. Coulson, 1992a. “Physical and mechanical properties of normal Portland cement pertaining to fully grouted cable bolts.” In Rock Support Min. Underground Construction. Rotterdam, Netherlands: A.A. Balkema.
Hyett, A. J., W. F. Bawden, and R. D. Reichert. 1992b. “The effect of rock mass confinement on the bond strength of fully grouted cable bolts.” Int. J. Rock Mech. Geomech. Abstr. 29 (5): 503–524. https://doi.org/10.1016/0148-9062(92)92634-O.
ISRM (International Society for Rock Mechanics), Commission on Standardization Laboratory and Field Results. 1978. “Suggested methods for determining hardness and abrasiveness of rocks.” Int. J. Rock Mech. Min. Sci. Geomech. Abstr. 15 (3): 89–97. https://doi.org/10.1016/0148-9062(78)90002-5.
Kang, H., N. Duolong, Z. Zhang, J. Lin, Z. Li, and M. Fan. 2010. “Deformation characteristics of surrounding rock and supporting technology of gob-side entry retaining in deep coal mine.” [In Chinese.] Chin. J. Rock Mech. Eng. 29 (10): 1977–1987.
Kang, H., T. Jiang, X. Zhang, and L. Yan. 2009. “Research on in-situ stress field in JinCheng mining area and its application.” [In Chinese.] Chin. J. Rock Mech. Eng. 28 (1): 1–8.
Li, W, J. Bai, J. Cheng, S. Peng, and H. Liu. 2015a. “Determination of coal–rock interface strength by laboratory direct shear tests under constant normal load.” Int. J. Rock Mech. Min. Sci. 77, 60–67. https://doi.org/10.1016/j.ijrmms.2015.03.033.
Li, W., J. Bai, S. Peng, X. Wang, and Y. Xu. 2015b. “Numerical modeling for yield pillar design: A case study.” Rock Mech. Rock Eng. 48 (1): 305–318. https://doi.org/10.1007/s00603-013-0539-8.
Li, X., M. Ju, Q. Yao, J. Zhou, and Z. Chong. 2015c. “Numerical investigation of the effect of the location of critical rock block fracture on crack evolution in a gob-side filling wall.” Rock Mech. Rock Eng. 49 (3): 1041–1058. https://doi.org/10.1007/s00603-015-0783-1.
Masoumi, H., H. Roshan, and P. C. Hagan. 2016. “Size-dependent Hoek-Brown failure criterion.” Int. J. Geomech. 17 (2): 04016048. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000706.
Medhurst, T. P., and E. T. Brown. 1998. “A study of the mechanical behaviour of coal for pillar design.” Int. J. Rock Mech. Min. Sci. 35 (8): 1087–1105. https://doi.org/10.1016/S0148-9062(98)00168-5.
Moosavi, M., W. F. Bawden, and A. J. Hyett. 2002. “Mechanism of bond failure and load distribution along fully grouted cable-bolts.” Trans. Inst. Min. Metall., Sect. A 111 (1): 1–12. https://doi.org/10.1179/mnt.2002.111.1.1.
Moosavi, M., and R. Grayeli. 2006. “A model for cable bolt-rock mass interaction: Integration with discontinuous deformation analysis (DDA) algorithm.” Int. J. Rock Mech. Min. Sci. 43 (4): 661–670. https://doi.org/10.1016/j.ijrmms.2005.11.002.
Najafi, M., A. Shishebori, and J. Gholamnejad. 2017. “Numerical estimation of suitable distance between two adjacent panels' working faces in shortwall mining.” Int. J. Geomech. 17 (4): 04016090. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000784.
Nie, W., Z. Y. Zhao, Y. J. Ning, and J. P. Sun. 2014. “Development of rock bolt elements in two-dimensional discontinuous deformation analysis.” Rock Mech. Rock Eng. 47 (6): 2157–2170.https://doi.org/10.1007/s00603-013-0525-1.
Ning, J., J. Wang, J. Jiang, S. Hu, L. Jiang, and X. Liu. 2018. “Estimation of crack initiation and propagation thresholds of confined brittle coal specimens based on energy dissipation theory.” Rock Mech. Rock Eng. 51 (1): 119–134. https://doi.org/10.1007/s00603-017-1317-9.
Oreste, P. P., and M. Cravero. 2008. “An analysis of the action of dowels on the stabilization of rock blocks on underground excavation walls.” Rock Mech. Rock Eng. 41 (6): 835–868. https://doi.org/10.1007/s00603-008-0162-2.
Salamon, M. 1990. “Mechanism of caving in longwall coal mining. Rock mechanics contributions and challenges.” In Proc., 31st US Symp. on Rock Mechanics, 161–168. Golden, CO: American Rock Mechanics Association.
Shen, W.-L., J.-B. Bai, W.-F. Li, and X.-Y. Wang. 2018. “Prediction of relative displacement for entry roof with weak plane under the effect of mining abutment stress.” Tunnelling Underground Space Technol. 71, 309–317. https://doi.org/10.1016/j.tust.2017.08.023.
Sun, C. D., D. S. Zhang, X. F. Wang, and R. Zhou. 2012. “Large-size test on creep characteristics of high water material for filling body beside roadway.” [In Chinese.] J. Min. Saf. Eng. 29 (4): 487–491. https://doi.org/10.1504/IJOGCT.2016.078049.
Tan, Y. L., X. S. Liu, J. G. Ning, and Y. W. Lu. 2017. “In situ investigations on failure evolution of overlying strata induced by mining multiple coal seams.” Geotech. Test. J. 40 (2): 244–257.https://doi.org/10.1520/GTJ20160090.
Tan, Y. L., F. H. Yu, J. G. Ning, and T. B. Zhao. 2015. “Design and construction of entry retaining wall along a gob side under hard roof stratum.” Int. J. Rock Mech. Min. Sci. 77, 115–121. https://doi.org/10.1016/j.ijrmms.2015.03.025.
Varadarajan, A., K. G. Sharma, S. M. Abbas, and A. K. Dhawan. 2006. “Constitutive model for rockfill materials and determination of material constants.” Int. J. Geomech. 6 (4): 226–237.https://doi.org/10.1061/(ASCE)1532-3641(2006)6:4(226).
Wang, X., J. Bai, W. Li, B. Chen, and V. D. Dao. 2014. “Evaluating the coal bump potential for gateroad design in multiple-seam longwall mining: A case study.” J. S. Afr. Inst. Min. Metall. 115 (8): 755–760. https://doi.org/10.17159/2411-9717/2015/v115n8a12.
Wang, M., J. Bai, W. Li, X. Wang, and S. Cao. 2015. “Failure mechanism and control of deep gob-side entry.” Arabian J. Geosci. 8 (11): 9117–9131. https://doi.org/10.1007/s12517-015-1904-6.
Wang, H, B. Poulsen, B. Shen, S. Xue, and Y. Jiang. 2011. “The influence of roadway backfill on the coal pillar strength by numerical investigation.” Int. J. Rock Mech. Min. Sci. 48 (3): 443–450. https://doi.org/10.1016/j.ijrmms.2010.09.007.
Wei, X. S. 2008. “Study on the surrounding rock control theory of gob-side entry returning in Wolonghu coal mine.” [In Chinese.] Xu Zhou, China: China Univ. of Mining and Technology.
Wilson, A. H., and F. Carr, 1982. “A new approach to the design of multi-entry developments of retreat longwall mining.” In Proc., 2nd Int. Conf. on Ground Control in Mining, 1–21. Morgantown, WV: The American Institute of Mining, Metallurgical, and Petroleum Engineers.
Xiao, Y., H. Liu, Y. Chen, J. Jiang, and W. Zhang. 2015. “State-dependent constitutive model for rockfill materials.” Int. J. Geomech. 15 (5): 969–970. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000421.
Yavuz, H. 2004. “An estimation method for cover pressure re-establishment distance and pressure distribution in the goaf of longwall coal mines.” Int. J. Rock Mech. Min. Sci. 41 (2): 193–205. https://doi.org/10.1016/S1365-1609(03)00082-0.
Yuan, L. 2009. “Theory and practice of integrated pillarless coal production and methane extraction in multiseams of low permeability.” Eng. Sci. 11, 72–80.
Zhang, L. 2010. “Estimating the strength of jointed rock masses.” Rock Mech. Rock Eng. 43 (4): 391–402. https://doi.org/10.1007/s00603-009-0065-x.
Zhang, Z., J. Bai, Y. Chen, and S. Yan. 2015. “An innovative approach for gob-side entry retaining in highly gassy fully-mechanized longwall top-coal caving.” Int. J. Rock Mech. Min. Sci. 80, 1–11. https://doi.org/10.1016/j.ijrmms.2015.09.001.
Zhang, G.-C., F. L. He, H.-G. Jia, and Y.-H. Lai. 2017. “Analysis of gateroad stability in relation to yield pillar size: A case study.” Rock Mech. Rock Eng. 50 (5): 1–16.https://doi.org/10.1007/s00603-016-1155-1.
Zhang, G., F. He, and L. Jiang. 2016. “Analytical analysis and field observation of break line in the main roof over the goaf edge of longwall coal mines.” Math. Prob. Eng. 2016 (9): 1–11. https://doi.org/10.1155/2016/4720867.
Zhang, J.-X., H.-Q. Jiang, X.-X. Miao, N. Zhou, and D.-F. Zan. 2013. “The rational width of the support body of gob-side entry in fully mechanized backfill mining.” [In Chinese.] J. Min. Saf. Eng. 30 (2): 159–164. https://doi.org/10.1080/20519842.2013.11415348.
Zhang, G, S. Liang, Y. Tan, F. Xie, S. Chen, and H. Jia. 2018. “Numerical modeling for longwall pillar design: A case study from a typical longwall panel in China.” J. Geophys. Eng. 15 (1): 121–134. https://doi.org/10.1088/1742-2140/aa9ca4.
Zhang, N., L. Yuan, C. Han, J. Xue, and J. Kan. 2012. “Stability and deformation of surrounding rock in pillarless gob-side entry retaining.” Saf. Sci. 50 (4): 593–599. https://doi.org/10.1016/j.ssci.2011.09.010.
Zhang, K., G. Zhang, R. Hou, Y. Wu, and H. Zhou. 2014. “Stress evolution in roadway rock bolts during mining in a fully mechanized longwall face, and an evaluation of rock bolt support design.” Rock Mech. Rock Eng. 48 (1): 333–344.https://doi.org/10.1007/s00603-014-0546-4.
Zhao, T.-B., W.-Y. Guo, Y.-L. Tan, C.-P. Lu, and C.-W. Wang. 2017. “Case histories of rock bursts under complicated geological conditions.” Bull. Eng. Geol. Environ. 1–17. https://doi.org/10.1007/s10064-017-1014-7.
Zhou, B.-J., J.-H. Xu, and H.-M. Ni. 2010. “The small aspect ratio backfill gob-side entry retaining stability.” J. China Coal Soc. 35 (S0): 33–37.
Information & Authors
Information
Published In
Copyright
© 2018 American Society of Civil Engineers.
History
Received: Aug 3, 2017
Accepted: Feb 15, 2018
Published online: Jun 5, 2018
Published in print: Aug 1, 2018
Discussion open until: Nov 5, 2018
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.