On the use of the Kozeny–Carman equation to predict the hydraulic conductivity of soils

Abstract

The saturated hydraulic conductivity of a soil can be predicted using empirical relationships, capillary models, statistical models, and hydraulic radius theories. A well-known relationship between permeability and the properties of pores was proposed by Kozeny and later modified by Carman. The resulting equation is largely known as the Kozeny–Carman (KC) equation, although the two authors never published together. In the geotechnical literature, there is a large consensus that the KC equation applies to sands but not to clays. This view, however, is supported only by partial demonstration. This paper evaluates the background and the validity of the KC equation using laboratory permeability tests. Test results were taken from publications that provided all of the information needed to make a prediction: void ratio, and, either the measured specific surface for cohesive soils, or the gradation curve for noncohesive soils. The paper shows how to estimate the specific surface of a noncohesive soil from its gradation curve. The results presented here show that, as a general rule, the KC equation predicts fairly well the saturated hydraulic conductivity of most soils. Many of the observed discrepancies can be related to either practical reasons (e.g., inaccurate specific surface value; steady flow not reached; unsaturated specimens, etc.) or theoretical reasons (some water is motionless; hydraulic conductivity of soils is anisotropic). These issues are discussed in relation to the predictive capabilities of the KC equation.Key words: permeability, prediction, gradation curve, specific surface.

Coupling distributed stormwater collection and managed aquifer recharge: Field application and implications

“…where and Aubertin, 2003) We compared sediment properties to soil types in the Natural Resource Conservation Service SSURGO database (Soil Survey Staff, U.S. Department of Agriculture, 2014). For each sample location in the infiltration basin, we calculated effective hydraulic conductivity (K eff ) at the end of WY13e15 (see SI).…”

A coupled THC model of the FEBEX in situ test with bentonite swelling and chemical and thermal osmosis

“…Although it could be argued that the KC equation in (8), which was initially derived mainly for granular materials, might not be adequate for low-permeability high-porosity materials such as bentonites, the results reported by Chapuis and Aubertin (2003) show that the KC equation predicts reasonably well the saturated hydraulic conductivity of most soils. Mauran et al (2001) showed also that the KC equation can be safely used for large-porosity media.…”

Enhanced Absorbent Products Incorporating Cellulose and Its Derivatives: A Review

“…Various approaches can be used to estimate the value of the coefficient k in the case of paper-like structures (Kozeny 1927;Carman 1938Carman , 1939Carrier 2002;Chapuis and Auberton 2003;Hubbe and Heitmann 2007). For instance, a simple laminar hydrodynamic model was used to derive the following expression,…”

“…where k is the permeability (distance of penetration per unit of time),  is a unit mass of the fluid,  is the fluid's dynamic viscosity, CK-C is the Kozeny-Carman coefficient (usually taken to be about 5), So is the specific surface area per unit displacement volume of particulate material, and e is the fractional void volume (Carrier 2002;Chapuis and Auberton 2003). Ingmanson (1952Ingmanson ( , 1953 applied similar concepts to the case of cellulosic fibers, taking into consideration the bulky structures formed by fibers, but also considering the compressibility of cellulose.…”