Assessing the Applicability of Sand Hydraulic Conductivity Calculation Techniques

Accurate evaluation of hydraulic conductivity is an important part of estimating water permeability of soils. The article describes the results of hydraulic conductivity evaluation for alluvial sands by field and laboratory methods, as well as by empirical equations. In field conditions, hydraulic conductivity was determined by pouring water in test pits, and in laboratory conditions—by filtration tube surveys. It was established that the discrepancy between the results obtained by laboratory methods and those obtained by field tests reaches 10–16%. Empirical formulas of Hazen, Kozeny-Carman, Slichter, Krüger, and Sauerbrey were used to calculate the hydraulic conductivity of sand. The deviation of the hydraulic conductivity value obtained by field survey from that obtained through calculation is 6–71%. The closest match was produced by the Krüger equation, which accounts for the specific surface area of particles. The article demonstrates that empirical equations based on effective diameter calculations give considerable errors in most cases. The error in determining hydraulic conductivity is also associated with the application of a standard set of sieves (to establish the grain size distribution of sand) featuring a large gap between opening sizes.