Examination of saturated hydraulic conductivity using grading curve functions

In a previous research program 74 artificial soil mixtures of natural fluvial soils were prepared in 4 series of measurements for falling head permeability testing, differing in d10. The conclusions drawn from the original investigations were as follows: the k showed a decreasing tendency with the increase of the uniformity index U for each series of measurements and increasing tendency with d10. In this research these are used (i) to test the value of the grading entropy parameters in case of nonprecise grading curve measurement with missing fines, (ii) to correlate the usual grading curve parameters like d10, d30, d50 and d60 or their ratios and the grading entropy parameters, (iii) to validate some existing permeability – grading curve equations and to elaborate some new permeability – grading curve relationships partly with entropy parameters partly with the usual parameters. For these aims, series I to IV have been started to be reevaluated, some specific surface formulae were derived. Some additional, literature data were also considered. The very first results are presented here. According to the results, the fine fractions significantly influenced the value of the entropy parameters. The base entropy So showed strong relationship with and parameters like d10, d30, d50 and d60. The entropy increment ΔS showed a monotonic increasing relationship with U. The specific surface parameter (containing density info) showed the best relationship with k out of the d-type parameters like d10 or harmonic mean dh. The original conclusions were reformulated in terms of S0 and and ΔS. It was also concluded that those parameters that are based on all measured data are more precise than the single diameter values in the k-regressions. The specific surface parameter is the best in this repect probably since containing density information, too.