Stability assessment of rock surrounding an I-beam supported retreating roadway

Abstract

The installation of a back-wall guard-board is the key to successfully supporting underground retreating roadways in coal mines. Based on the coordinate support principle, and using an I-shaped steel support for the surrounding rock, a mechanical model was developed for the stability of the roadway support and surrounding rock. Analysis of the bearing capacity of the roof back-wall guard-board and modelling of the equations for the maximum deflection and the maximum compressive stress of the top and side beams of the I-shaped steel support were undertaken. Simultaneously, the model was used to calculate and analyse the stability of the top and side beams of the I-shaped steel support structure and analyse the criteria for their stability. The results provide a reliable theoretical basis for the judgment of the stability of the surrounding rock and support structure. The theoretical evaluation results are consistent with field data. Finally, the key support parameters of the top and side beams of the I-shaped steel support structure and the variation of the maximum deflection and the maximum compressive stress as affected by the influence of the guard-board length were investigated. It is concluded that, as the back-board length increases, the maximum compressive stress in the top beam of the I-shaped steel support increases while the compressive stress in the side beam decreases. The results show that the accuracy of judgment of the stability of a supported retreating roadway is improved, providing guidance for the design of such typical I-shaped steel support and back-board structures.

Keywords

mine support / retreating roadway / mechanical model / back-wall guard-board / stability assessment

References

[1] UnalE, OzkanI, CakmakciG. Modeling the behaviour of longwall coal mine gate roadways subjected to dynamic loading [J]. Int J Rock Mech Min Sci, 2001, 38(2): 181-197

[2] GongF-q, LiX-b, GaoKe. 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

[3] XiaoT-q, WangX-y, ZhangZ-g. Stability control of surrounding rocks for a coal roadway in a deep tectonic region [J]. International Journal of Mining Science and Technology, 2014, 24(2): 171-176

[4] JiaoY-y, SongL, WangX-z, AmoussouC A. Improvement of the U-shaped steel sets for supporting the roadways in loose thick coal seam [J]. Int J Rock Mech Min Sci, 2013, 60(1): 19-25

[5] ZhangN, WangC Z Y-ming. Rapid development of coalmine bolting in China [J]. Proced Earth Planet Sci, 2009, 1(1): 41-46

[6] JukesS G, HassaniF P, WhittakerB N. Characteristics of steel arch support systems for mine roadways. Part. 1. Modelling theory, instrumentation and preliminary results [J]. Mining Science and Technology, 1983, 1(1): 43-58

[7] SzwilskiA B. Experience with mine roadway steel arch supports in the United Kingdom [J]. Mining Science and Technology, 1979, 72(2): 92-96

[8] KhanU H, MitriH S, JonesD. Full scale testing of steel arch tunnel supports [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1996, 33(3): 219-232

[9] WhittakerP E. Strata loading of mine roadway supports [J]. Mining Science and Technology, 1984, 2(1): 45-56

[10] JukesS G, SmithS F. Study of deformation behaviour of steel arches in gate roadways [J]. Mining Science and Technology, 1985, 3(1): 63-80

[11] JukesS G, HassaniF P, WhittakerB N. Characteristics of steel arch support systems for mine roadways. Part 2. Effect of strutting [J]. Mining Science and Technology, 1984, 2(1): 107-121

[12] MitriH S, HassaniF P. Structural characteristics of coal mine steel arch supports [J]. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1990, 27(2): 121-127

[13] MitriH S, HassaniF P. Nonlinear finite element analysis of mine roadway arch support systems [J]. Computers & Structures, 1988, 29(3): 355-364

[14] EarlsC J. Constant moment behavior of high-performance steel I-shaped beams [J]. Journal of Constructional Steel Research, 2001, 57(7): 711-728

[15] HouC-jGround control of roadways [M], 2013XuzhouChina University of Mining and Technology Press308-326

[16] MaN-j, LiB-y. Research on the steel I-shaped beam and its application [J]. Jiangsu Coal, 1989, 6(4): 20-25

[17] LuS-l, TangL. Working resistance of bolts and frame-type support in roadways with severe rock deformation [J]. Journal of China Coal Society, 1998, 23(4): 371-375

[18] JiangB-s, ChenZ-y. Theory for calculation of yieldable steel arch [J]. Journal of China Coal Society, 1994, 19(5): 493-503

[19] LiuH-wMechanics of materials [M], 2004BeijingHigher Education Press1-426

[20] QianM-g, MiaoX-x, XuJ-lTheory of key stratum in ground control [M], 2003XuzhouChina University of Mining and Technology Press1-234