Desiccation of Mineral Liners Below Landfills with Heat Generation
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 123, Issue 11
Abstract
In the case of landfills with heat generation, the long-term efficiency of composite liners at the landfill base is imperiled by desiccation and subsequent cracking of the mineral liner below the geomembrane. Downward vapor diffusion due to temperature gradients leads to desiccation unless it can be balanced by capillary rise. A numerical model (SUMMIT) of coupled transport of water, vapor, and heat in unsaturated porous media was developed to assess the landfill-specific desiccation risk of mineral liners (in terms of matric potentials). Water retention and unsaturated hydraulic conductivity of mineral liner and subsurface materials were measured. Simulations of nonisothermal lab and field experiments show that nonisothermal vapor diffusion can be up to five times higher than is physically explainable. Matric potentials in the mineral liner decrease (and thus the risk of cracking increases) with decreasing unsaturated hydraulic conductivity and water capacity, and increasing air porosity and distance to ground water. Desiccation simulations for typical landfill conditions show that the drainage layer directly beneath the mineral liner will most probably lead to cracking.
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References
1.
Bach, L. B.(1992). “Soil water movement in response to temperature gradients: experimental measurements and model evaluation.”Soil Sci. Soc. Am. J., 56(1), 37–46.
2.
Bishop, A. W., and Blight, G. E.(1963). “Some aspects of effective stress in saturated and partly saturated soils.”Géotechnique, London, England, 13, 177–195.
3.
Celia, M. A., Bouloutas, E. T., and Zarba, R. L.(1990). “A general mass-conservative numerical solution for the unsaturated flow equation.”Water Resour. Res., 26(7), 1483–1496.
4.
de Vries, D. A. (1963). “Thermal properties of soils.”Physics of plant environment, W. R. van Wijk, ed., John Wiley & Sons, Inc., New York, N.Y., 210–235.
5.
Döll, P. (1996). “Modeling of moisture movement under the influence of temperature gradients: desiccation of mineral liners below landfills,” PhD thesis, Tech. Univ. of Berlin, Germany.
6.
Freyer. (1989). “Comparison of six methods to determine unsaturated hydraulic conductivity.”UNSODA unsaturated soil hydraulic database 1994, F. J. Leij, W. J. Alves, M. T. van Genuchten, and J. R. Williams, eds., Robert S. Kerr Envir. Res. Lab., U.S. Envir. Protection Agency, Ada, Okla.
7.
Gottheil, K.-M., and Brauns, J. (1995). “Thermische Einflüsse auf die Dichtwirkung von Kombinationsdichtungen—Messungen an einem Testfeld (Thermal influences on the sealing efficiency of composite liners—measurement at a test site).”Proc. 3. Arbeitstagung des BMBF-Verbundforschungsvorhaben Weiterentwicklung von Deponieabdichtungssystemen, Bundesanstalt für Materialforschung und -prüfung, Berlin, Germany, 175–184.
8.
Holzlöhner, U. (1990). “Langzeitverhalten von mineralischen Abdichtungsschichten in Deponieabdichtungen hinsichtlich Austrocknung und Rißbildung (Long-term behavior of mineral liners with respect to desiccation and cracking).”Rep. 10203412 Part III, Bundesanstalt f. Materialforschung und -prüfung, Berlin, Germany.
9.
Holzlöhner, U.(1992). “Austrocknung und Rißbildung in mineralischen Schichten der Deponiebasisabdichtung (Desiccation and cracking in mineral layers of the landfill base liner).”Wasser und Boden, Hamburg, Germany, 5, 289–293.
10.
Jury, W. A. (1973). “Simultaneous transport of heat and moisture through a medium sand,” PhD thesis, University of Wisconsin.
11.
Jury, W. A., and Letey, J.(1979). “Water vapor movement in soil: reconciliation of theory and experiment.”Soil Sci. Soc. Am. J., 43(5), 823–827.
12.
Kay, B. D., and Groenevelt, P. H.(1974). “On the interaction of water and heat transport in frozen and unfrozen soils: I. basic theory; the vapor phase.”Soil Sci. Soc. Am. Proc., 38(3), 395–400.
13.
Luikov, A. V.(1975). “Systems of differential equations of heat and mass transfer in capillary-porous bodies (review).”Int. J. Heat Mass Transfer, 18(3), 1–14.
14.
Melchior, S. (1993).“Wasserhaushalt und Wirksamkeit mehrschichtiger Abdecksysteme für Deponien und Altlasten (Water balance and efficiency of multiple surface liner systems for landfills and contaminated sites),” PhD thesis, Univ. of Hamburg, Germany.
15.
Milly, P. C. D.(1982). “Moisture and heat transport in hysteretic, inhomogeneous porous media: a matric head-based formulation and a numerical model.”Water Resour. Res., 18(3), 489–498.
16.
Milly, P. C. D.(1984). “A simulation analysis of thermal effects on evaporation from soil.”Water Resour. Res., 20(8), 1087–1098.
17.
Mualem, Y.(1976). “A new model for predicting the hydraulic conductivity of unsaturated porous media.”Water Resour. Res., 12(3), 513–522.
18.
Philip. J. R., and de Vries(1957). “Moisture movement in porous materials under temperature gradients.”AGU Trans., 38(2), 222–232.
19.
Reece, C. F.(1996). “Evaluation of a line heat dissipation sensor for measuring soil matric potential.”Soil Sci. Soc. Am. Proc., 60(4), 1022–1028.
20.
Stoffregen, H. (1997). “Einfluß von Temperatur und Temperaturgradienten auf die Wasserbewegung im Boden (Influence of temperature and temperature gradients on water movement in soil),” PhD thesis, Tech. Univ. of Berlin, Germany.
21.
Taylor, S. A., and Cary, J. W. (1964). “Linear equations for the simultaneous flow of matter and energy in a continuous soil system.”Soil Sci. Soc. Am. Proc., 28(2), 167–172
22.
van Genuchten, M. T.(1989). “A closed-form equation for predicting the hydraulic conductivity of unsaturated soils.”Soil Sci. Soc. Am. J., 44(5), 892–898.
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Copyright © 1997 American Society of Civil Engineers.
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Published online: Nov 1, 1997
Published in print: Nov 1997
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