A Formulation for Scanning Soil-water Characteristic Curves

The hysteretic nature of soil water characteristic curve (SWCC) is captured assuming the virgin drying and virgin wetting (a.k.a. imbibition) curves; which can be obtained from experiments or various fitting equations in the literature, bound all possible values during transition from one regime to the other. The scanning curves (transitions between virgin wetting and drying SWCC) are modelled by using geometry-based relations, which are devised by means of the observations on the shapes of graphs of experimental data found in the literature. The proposed relations can be used in incremental form to predict suction in different frameworks (e.g. infiltration, evaporation) and related physical problems. An empirical equation is proposed for power parameter (K), which is introduced in the relations. Only virgin wetting and virgin drying SWCCs and regime reversal point suffice to model a scanning curve in the developed formulations.

A Formulation for Scanning Soil-water Characteristic Curves

The hysteretic nature of soil water characteristic curve (SWCC) is captured assuming the virgin drying and virgin wetting (a.k.a. imbibition) curves; which can be obtained from experiments or various fitting equations in the literature, bound all possible values during transition from one regime to the other. The scanning curves (transitions between virgin wetting and drying SWCC) are modelled by using geometry-based relations, which are devised by means of the observations on the shapes of graphs of experimental data found in the literature. The proposed relations can be used in incremental form to predict suction in different frameworks (e.g. infiltration, evaporation) and related physical problems. An empirical equation is proposed for power parameter (K), which is introduced in the relations. Only virgin wetting and virgin drying SWCCs and regime reversal point suffice to model a scanning curve in the developed formulations.

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  • [1] Miller, G.A., Khoury, C.N., Muraleetharan, K.K., Liu, C., and Kibbey, T.C.G. "Effects of soil skeleton deformations on hysteretic soil water characteristic curves: Experiments and simulations". Water Res. Res. 44, W00C06, (2008).
  • [2] Lins, Y., Zou, Y., and Schanz, T. "Physical modelling of SWCC for granular materials". Theoretical and numerical unsaturated soil mechanics, Weimar, Germany, 61-74, (2007).
  • [3] Hammervold, W.L., Knutsen, Ø., Iversen, J.E., and Skjæveland, S.M. "Capillary pressure scanning curves by the micropore membrane technique". Journal of Petroleum Science and Engineering 20: 253-258, (1998).
  • [4] Viane, P., Vereecken, H., Diels, J., and Feyen, J. "A statistical analysis of six hysteresis models for the moisture retention characteristic". Soil Sci. 157: 345-355, (1994).
  • [5] Watson, K.K., Reginato, R.J., Jackson, R.D. "Soil water hysteresis in a field soil". Soil Sci. Soc. America J. 157: 345-355, (1975).
  • [6] Topp, G.C. "Soil water hysteresis in silt loam and clay loam soils". Water Res. Res. 7: 914-920, (1971).
  • [7] Li, X.S. "Modelling of hysteresis response for arbitrary wetting/drying paths". Computers and Geotechnics, 32(2): 133-137, (2005).
  • [8] Pedroso, D.M., and Williams, D.J. "A novel approach for modelling soil- water characteristic curves with hysteresis". Computers and Geotechnics, 37(3): 374-380, (2010).
  • [9] Van Genuchten, M.T. "A closed-form equation for predicting the hydraulic conductivity of unsaturated soils", Soil Sci. Soc. Am. J. 44: 892-898 ,(1980).
  • [10] Lins, Y., Zou, Y., and Schanz, T. "Physical modelling of SWCC for granular materials". Theoretical and numerical unsaturated soil mechanics, Weimar, Germany, 61-74, (2007).
  • [11] Talsma, T. "Hysteresis in two sands and the independent domain model". Water Resources Research 6(3): 964-970, (1970).
  • [12] Poulovassilis, A., and Childs, E.C. "The hysteresis of pore water: The non- indepence of domains". Journal of Soil Science, 112(5): 301-312, (1971).
  • [13] Sakai,M., and Toride, N. "Soil water hydraulic functions for sandy soil and an aggregated soil". J. Jpn. Soc. Soil Ohys., 107: 63-77, (2007).
  • [14] Dane, J.H., and Hruska, S. "In-situ determination of soil hydraulic properties during drainage". Soil Sci. Soc. Am. J., 4: 619-624, (1983).
  • [15] Haverkamp, R., Arrue, J.L., and Soet, M. "Soil physical properties within the root zone of the vine area of Tomelloso". Local and spatial standpoint, In Final integrated report of EFEDA II (European Field Experiment in a Desertification Area) Spain, Ed. J. F. Santa Olalla, CEE project n° CT920092, Brussels, chapter 3, (1997).
  • [16] Gillham, R.W., Klute, A., and Heermann, D.F. "Hydraulic properties o a porous medium: Measurement and empirical representation." Soil Science Society of America Journal, 40: 203-207, (1976).
  • [17] Huang, H.C., Tan, Y.C., Liu, C.W., and Chen, C.H. "A novel hysteresis model in unsaturated soil." Hydrol. Processes 19:1653-1665. doi:10.1002/hyp.5594, (2005).
  • [18] Chen, P., Wei, C. F., and Ma, T. T. (2015). “Analytical model of soil-water characteristics considering the effect of air entrapment.” Int. J. Geomech., 10.1061/(ASCE)GM.