Estimation of soil water retention curve: An asymmetrical pore-solid fractal model

Abstract

The soil water retention curve is an important hydraulic function for the study of flow transport processes in unsaturated soils. The objective of this study was to develop a soil water retention function using a generalized fractal approach. The model exhibits asymmetry between the solid phase and pore phase, which is in marked contrast to the symmetry between phases present in a conventional fractal model. The retention function includes 4 parameters: the saturated water content θ s , the air entry value h a , the fractal dimension D f , and an empirical parameter β, characterizing the complicated soil pore structures. Sixty one data sets, covering a wide range of soil structure and textural properties, were used to evaluate the applicability of the proposed soil water retention function. The retention function is shown to be a general model, which incorporates several existing retention models. The values of β/θ s and (θ s −θ r )/β were used as indexes to quantify the relationships between the proposed retention function and the existing retention models. The proposed function fits all the data very well, whereas other tested models only match about 16%-48% of the soil retention data.

Determining Soil-Water Characteristic Curves from Mercury Intrusion Porosimeter Test Data Using Fractal Theory

“…Perrier et al [14] and Xu et al [15,16] proposed SWCC models employing a fractal model of the pore volume distribution, which was developed on the basis of Mandelbrot's model expressing the relationship between volume and quantity distribution of fractal matter. Many contributions rely on the pore-solid fractal model to 2 of 15 establish fractal SWCC models of PSD [17][18][19][20]. Ghanbarian-Alavijeh and Millan [21] researched the relationship between surface fractal dimensions derived from SWCC and water content remaining at high tensions as well as clay content.…”

Mitigating N2O emissions from agriculture: A review of the current knowledge on soil system modelling, environmental factors and management practices influencing emissions

“…In particular, the pore-solidfractal approach (Perrier et al, 1999) allows derivation of a theoretical water retention curve (Wang and Zhang, 2011) and provides a 3D-space in which to simulate several key processes, including the temporal dynamics of the anoxic fraction of the pore volume (Rappoldt and Crawford, 1999).…”

“…Another approach involves using soil structural models as a pre-process tool to provide pedotransfer functions to be later used in a more generic model. In this regard, the pore-solid-fractal approach (PSF) derived by Perrier et al (1999) has proved to be a powerful tool that is able to account for a wide variety of soil physical properties (Ghanbarian-Alavijeh et al, 2011;Perfect and Kay, 1995), such as the theoretical water retention curve derived by Wang and Zhang (2011). Rappoldt and Crawford (1999) used the 3D-soil space resulting from the PSF model in order to solve the oxygen diffusion-respiration equation in soils.…”

Fractal Modeling Research in Permeability of Camellia and Bancoul Nut Cakes under Cold-Press

“…Darcy first studied permeability, establishing the Darcy law to reflect the pore seepage rule. Currently, the Darcy law has been widely applied in the permeability study of porous media [3,4,5 ].…”

“…Currently, a permeability fractal model of oilseed cakes has been established by combining the Darcy law with the Hagen-Poiseuille modification formula. Additionally, the model calculated values were compared with the experimental values [3].…”