An evaluation of air permeability measurements to characterize the saturated hydraulic conductivity of soil reclamation covers

Abstract

The saturated hydraulic conductivity (Ks) of soil covers used in land reclamation is known to change over time as the result of weathering processes. Guelph permeameter (GP) measurements have been used to track the evolution of Ksfor soil covers at an oil sands mine near Ft. McMurray , Alberta. Although successful, the method was time consuming and consequently a rapid method of estimating Ksbased on in situ air permeability measurements was developed. The objectives of this study were: (1) to use air permeability measurements to characterize the spatial variations of Ksfor typical reclamation soils and (2) to compare air permeability measurements to direct measurements obtained through laboratory and GP measurements. The results highlight that the values of Ksestimated from measured air permeability values were higher than the values of Ksmeasured directly using the GP. This is likely due to swelling of clay soils or air-entrapment during GP measurements. Although the magnitude was over-estimated, the variability of Kswas captured by the air permeability measurements. Consequently, a limited program of comparative GP and air permeameter measurements could be used to more rapidly characterize the Ksof reclamation covers over time.