Summary
This paper develops a rational approach for design of coal pillars under weak floor strata conditions considering ultimate bearing capacity (UBC) as well as pillar settlement. An approximate solution is presented for estimation of UBC for a shallow foundation on a two-layered rock system with consideration of both cohesion (c) and (ø) for both layers. Similarly, deformability underneath a full-size pillar is estimated from deformability calculated from plate loading tests. The effect of adjacent pillars on UBC and deformability of coal pillars in a panel is considered using foundation engineering analysis techniques. The design of pillars based on limiting settlements considers both differential settlements as well as mean settlement of pillar in a panel. An attempt is made to validate the proposed design approach based on field data and observations at an Illinois mine.
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References
Bond, D. (1961) The influence of foundation size on settlement,Geotechnique,2, pp. 121–43.
Brinch-Hansen, J. (1968) A revised and extended formula for bearing capacity, Preprint of Lecture in Japan.
Brown, J.D. and Meyerhof, G.G. (1969) Experimental study of bearing capacity in layered clays,Proc. 7th ICSMFE, Mexico City,2, pp. 45–51.
Burmister, D.M. (1956) Stresses and displacement characteristics of a two-layer rigid base soil system: influence diagnose and practical applications,Proceedings, Highway Res. Board,35, p. 773.
Button, S.J. (1953) The bearing capacity of footings on a two-layer cohesive subsoil,Proc. 3rd ICSMFE, Zurich,1, pp. 332–5.
Caquot, A. and Kerisel, J. (1953) Sur le Terme de Surface dans le Calcul des Fondations en Milieu Pulverulent,Proc. 3rd ICSMFE, Zurich,1, pp. 336–7.
Chugh, Y.P. (1986) In situ strength characteristics of coal mine floor strata in Illinois.Final Report, Department of Mining Engineering, SIU at Carbondale.
Chugh, Y.P. and Atri, A. (1988) Laboratory and field characterization of immediate floor strata in Illinois coal mines,Final Report to Illinois Mine Subsidence Research Program, Champaign, IL.
Chugh, Y.P., Atri, A. and Dougherty, J. (1989) Laboratory and field characterization of immediate floor strata in Illinois basin coal mines,Proc. of the 30th U.S. Symposium on Rock Mechanics, West Virginia University, Morgantown, 19–22 June 1989, pp. 47–54.
Giroud, J.P. (1972) Settlement of rectangular foundation on soil layer,ASCE J. of Soil Mech. and Found. Div.,98, pp. 149–54.
Graham, J., Raymond, G.P. and Suppiah, A. (1984) Bearing capacity of three closely-spaced footings on sand,Geotechnique,34, No. 2, pp. 173–82.
Hanna, A.M. (1982) Bearing capacity of Foundations on a weak sand layer overlying a strong deposit,Can. Geotech. J.,19, pp. 392–9.
Herdy, A.C. and Townsend, F.C. (1982) Preliminary investigation of bearing capacity of layered soils by centrifugal modeling,Trans. Res. Rec. 872, pp. 20–4.
Janbu, N., Bjerrum, L. and Kjaernsli, B. (1956) Norwegian Geotech. Inst. Publ., 16, Oslo.
Koegler, F. and Scheidig, A. (1938) Baugrunde und Bauwerk, Ernst, Berlin, p. 288.
Livneh, M. (1965) The theoretical bearing capacity of soils on a rock foundation,Proc. 6th ICSMFE, Montreal,2, pp. 122–6.
Livneh, M. and Greenstein, J. (1973) The bearing capacity of footings on non-homogenous clay,Proc. 8th ICSMFE, Moscow,2, pp. 219–23.
Mandel, J. (1965) Interference plastique de semmelles filantes,Proc. 6th ICSMFE, Montreal,3, pp. 127–31.
Mandel, J. and Salencon, J. (1969) Force portante d'un sol sut une assise rigide,Proc. 7th ICSMFE, Mexico City,2, pp. 157–64.
Meyerhof, G.G. (1974) Ultimate bearing capacity of footing on sand layer overlying clay,Can. Geotech, J.,11, pp. 223–9.
Myslivec, A. and Kysela, Z. (1978) The bearing capacity of building foundations,Elsevier Sc. Publ. Comp., Amsterdam, pp. 134–8.
Perloff, W.H. (1975) Pressure distribution and settlement inFoundation Engineering Handbook (edited by H. Wintercorn and Hsai-Yang Fang), Van Nostrand Reinhold Company, pp. 148–9.
Pula, O. and Rybak, C. (1981) Sur l'interaction de semelles filantes dans le domaine plastique,Proc. 10th ICSMFE, Stockholm,2, pp. 235–7.
Pytel, W.M. (1988) Development of an analytical model for solving roof-coal pillar-floor interaction problems,Internal Research Report, Dept. of Mining Engineering, Southern Illinois University at Carbondale.
Pytel, W.M., Chugh, Y.P., Zabel, B. and Caudle, R. D. (1988) A simplified two-dimensional analysis of the roof-pillar-floor interaction problem in coal mines,Proc. 7th Int. Conf. on Ground Control in Mining, (edited by S. S. Peng), Morgantown, WV, pp. 271–81.
Pytel, W.M. and Chugh, Y.P. (1989) An analysis of roof-pillar-weak floor interaction in partial extraction room-and-pillar mining,Proc. 30th U.S. Symposium on Rock Mechanics (edited by A. Wahab Khair), Morgantown, WV, pp. 621–8.
Rockaway, J.D. and Stephenson, R.W. (1974)Investigation of the Effects of Weak Floor Conditions on the Stability of Coal Pillars, Dept. of Mining, Petroleum and Geological Engineering and Dept. of Civil Engineering, Univ. of Missouri-Rolla.
Salencon, J., Barbier, M. and Benbat, M. (1973) Force portante d'une foundation sur sol non-homogenee,Proc. 8th ICSMFE, Moscow,2, pp. 219–23.
Shield, R.T. (1955) The plastic indentation of a layer by a flat punch.Q. Appl. Math,XIII (1), pp. 27–46.
Steinbrenner, W. (1936) Tafeln zur Setzungberechnung Die Strasse,1, pp. 121–24.
Stuart, J.G. (1962) Interference between foundations with special reference to surface footings on sand.Geotechnique,12, (i), pp. 15–20.
Suklje, L. (1954) Capacite portante des couches cohesives peu permeables et d'epaisseur limitee,Proc. Yugoslav Soc. of Soil Mech. and Found. Eng., No. 3, pp. 16–26.
Terzaghi, K. (1943)Theoretical Soil Mechanics, John Wiley, New York, Chap. 8.
Terzaghi, K. and Peck, R.B. (1968)Soil Mechanics in Engineering Practice, John Wiley, New York.
Vesic, A. S. (1970) Research on Bearing Capacity of Soils (unpublished).
West, J.M. and Stuart, J.G. (1965) Oblique loading resulting from interference between surface footings on sand,Proc. 6th ICSMFE, Montreal,3, pp. 214–17.
Wilun, Z. and Starzewski, K. (1972)Soil Mechanics and Foundations Engineering, John Wiley, New York — Toronto, p. 41.
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Chugh, Y.P., Pula, O. & Pytel, W.M. Ultimate bearing capacity and settlement of coal pillar sub-strata. International Journal of Mining and Geological Engineering 8, 111–130 (1990). https://doi.org/10.1007/BF00920499
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DOI: https://doi.org/10.1007/BF00920499