On the Compaction Curve of the Kanto Loam and its Permeability 2

Abstract

(1) The Kanto Loam has the minimum permeability if it is compacted at natural moisture content (cf. the report I). One of these causes is the fact that the Kanto Loam fresh soil has much nonfree water.
(2) Because of this reason, the saturated permeability (k_sat) of compacted fresh soil changes with hydraulic gradient. The value of k_sat is constant in the range where hydraulic gradint is small, but in the range of great gradient, the value of k_sat increases proportionaly with a hydraulic gradient, and beyond the latter range k_sat decreases.
But k_sat is constant in the case where oven dry soil is compacted. This phenomenon can be explained by the hypothesis that the volume of free water (being able to flow) and non free water (being unable to flow) change with hydraulic gradient.
(3) This phenomenon can be modelled with the combination of two formulae by the Hagen-Poiseuille and the Buckigham.