Abstract
Abstract. In this paper, the results of permeability and specific surface area analyses as functions of granulometric composition of various sediments (from silty clays to very well graded gravels) are presented. The effective porosity and the referential grain size are presented as fundamental granulometric parameters expressing an effect of the forces operating on fluid movement through the saturated porous media. This paper suggests procedures for calculating referential grain size and determining effective (flow) porosity, which result in parameters that reliably determine the specific surface area and permeability. These procedures ensure the successful application of the Kozeny–Carman model up to the limits of validity of Darcy's law. The value of effective porosity in the referential mean grain size function was calibrated within the range of 1.5 µm to 6.0 mm. The reliability of the parameters applied in the KC model was confirmed by a very high correlation between the predicted and tested hydraulic conductivity values (R2 = 0.99 for sandy and gravelly materials; R2 = 0.70 for clayey-silty materials). The group representation of hydraulic conductivity (ranging from 10−12 m s−1 up to 10−2 m s−1) presents a coefficient of correlation of R2 = 0.97 for a total of 175 samples of various deposits. These results present new developments in the research of the effective porosity, the permeability and the specific surface area distributions of porous materials. This is important because these three parameters are critical conditions for successful groundwater flow modeling and contaminant transport. Additionally, from a practical viewpoint, it is very important to identify these parameters swiftly and very accurately.
Highlights
The effect of the granulometric composition of granular porous media on its transmissivity, accumulation and suction parameters is both a permanent scientific challenge and a practical issue
This paper suggests procedures for calculating referential grain size and determining effective porosity, which result in parameters that reliably determine the specific surface area and permeability
The group representation of hydraulic conductivity presents a coefficient of correlation of R2 = 0.97 for a total of 175 samples of various deposits. These results present new developments in the research of the effective porosity, the permeability and the specific surface area distributions of porous materials
Summary
The effect of the granulometric composition of granular porous media on its transmissivity, accumulation and suction parameters is both a permanent scientific challenge and a practical issue. Hazen (1892) and Slichter (1902) have published widely accepted and reputable models for calculating the hydraulic conductivity of uniform sands using effective grain size. Hazen’s formula uses D10 (soil particle diameter where 10 % of all soil particles are finer (smaller) by weight), and Slichter proposes using the mean diameter. This confusion persisted, and in recent decades grain size D10 has been misused frequently (Kovács, 1981; Vukovic and Soro, 1992; Cheng and Chen, 2007; Odong, 2008) in formulae that use another effective grain size
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