Abstract
Effective stress law of all kinds of coal samples, including steam coal, fat coal, corking coal, thin coal and anthracite, under pore pressure of gas, is experimentally studied using a newly developed test machine. These samples are taken from Coal Mines in Wuda, Hebi, Yanzhou, Yangquan, Qingshui, and Gujiao in China. The experiment results show that, under pore pressure of gas, the tested coal samples comply with Biot’s effective stress law,\({\sigma '}_{ij} = {\sigma}_{ij} - {\alpha}p{\delta}_{ij}\)where the Biot’s coefficient α is not a constant, and is bilinear function of volumetric stress (Θ) and pore pressure (p), that is,\(\alpha = a_1 + a_2 \Theta + a_3 p + a_4 \Theta p\)We define four areas according to the numerical feature of α, that is, functionless area of pore pressure, normal function area, fracturing function area, and quasi-soil function area. The effective stress law of coal mass introduced by this paper is a constitutive equation in the study of coupled solid and fluid. This has significance in the drainage and outburst of methane in coal seam.
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References
Terzaghi, Theoretical Soil Mechanics, Wiley, New York, 1943.
Jeager, J. C. and Cook, N. G. W.: Fundamental of Rock Mechanics, 3rd edn, Chapman & Hall, London, 1979.
Boricenko, A. A.: Effect of gas pressure on stress in coal seam, Sov. Min. Sci. (1) (1985), 88–91.
Ettinger, A. L.: Swelling stress in the gas—coal system as an energy source in the development of gas bursts, Sov. Min. Sci. (5) (1979), 494–501.
Yangsheng, Z.: Rock—fluid Mechanics in Mine, Coal Industry Publishing of China, Beijing, China, 1994 (in Chinese).
Nur, A. and Byerlee, J. D.: An extract effective stress law for elastic deformation of rock with fluid, J. Geophys. Res. 76(26) (1971), 6414–6419.
Carroll, M. M.: A effective stress law for anisotropic elastic deformation, J. Geophys. Res. 84(13) (1979), 7510–7512.
Walsh, J. B.: The effect of cracks on the compressibility of rock, J. Geophys. Res. 70 (1965), 381–389.
Robin, P. Y. F.: Note on effective pressure, J. Geophys. Res. 78(14) (1973), 2434–2437.
Skempton, A. W.: Effective Stress in Solid Concrete and Rock Pore Pressure and Suction in Soils, Butterworths, London, 1960.
Bear, J.: Dynamics of Fluids in Porous Media, American Elsevier Publishing Company, Inc., New York, 1972.
Biot, M. A.: General theory of three-dimensional consolidation, J. Appl. Phys. 12 (1941), 155–164.
Geertsma, J.: The effect of fluid pressure decline on volumetric changes of porous rock, Trans. AIME (1957), 331–340.
Huyakorn, P. S. and Pinder, G.: Computational Methods in Subsurface Flow, Academic Press, New York, 1983.
Liggett, J. A. and Liu, P. L. F.: The Boundary Integral Equation Method for Porous Media Flow, George Allen & Unwin, London, 1983.
Verruijt, A.: An elastic storage of aquifers, Flow through Porous Media, Academic Press, New York, 1969, pp. 331–376.
Biot, M. A. and Willis, D. G.: The elastic coefficients of the theory of consolidation, J. Appl. Mech. 24 (1957), 594–601.
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Yangsheng, Z., Yaoqing, H., Jingping, W. et al. The Experimental Approach to Effective Stress Law of Coal Mass by Effect of Methane. Transport in Porous Media 53, 235–244 (2003). https://doi.org/10.1023/A:1025080525725
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DOI: https://doi.org/10.1023/A:1025080525725