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Transient Flow from Tension Infiltrometers II. Four Methods to Determine Sorptivity and Conductivity
Author(s) -
Vandervaere Jean-Pierre,
Vauclin Michel,
Elrick Dave E.
Publication year - 2000
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2000.6441272x
Subject(s) - sorptivity , infiltrometer , hydraulic conductivity , rotational symmetry , mathematics , mechanics , radius , infiltration (hvac) , flow (mathematics) , capillary action , transient (computer programming) , geotechnical engineering , mathematical analysis , physics , geology , thermodynamics , soil water , soil science , computer science , computer security , porosity , operating system
In Vandervaere et al. (2000) it was shown that the transient regime of axisymmetric infiltration can be described by a two‐term equation with one term proportional to the square root of time and the other term proportional to time. The two corresponding coefficients, C 1 and C 2 , are functions of the hydraulic conductivity, K , and the sorptivity, S In this paper we propose four different methods to achieve the determination of S and K The four methods differ by the number of disk radii and the number of supply pressure head values which are utilized. We show that the accuracy of a given method is highly dependent on the combination of S and K values obtained. Three situations can be distinguished, depending on the disk radius: (i) the flow is dominated by the lateral capillary term; (ii) the flow is dominated by the gravity term; (iii) lateral capillary and gravity terms have equivalent weights. The seven model soils tested here all correspond to the first situation with usual disk radius values. This tends to show that a precise estimation of K is unlikely from disk infiltrometer data. We introduce a new time scale, t stab , which generalizes the concepts corresponding to the two well known time scales t grav and t geom We propose a guideline for the investigator to choose between all existing methods of analysis that use steady or transient flow. Finally, the four new methods are tested against numerically simulated tests with Grenoble sand and Yolo light clay.