Characterizing the spatial variability of the hydraulic conductivity of reclamation soils using air permeability

摘要

The saturated hydraulic conductivity (KO is a key property in the design of reclamation soils, influencing key aspects of the water balance including infiltration and net percolation. The conventional field method of measuring K-s for reclamation soils has been the use of water infiltration tests such as the Guelph permeameter (GP). However, the time required to conduct a large number of water infiltration tests can make it difficult to obtain a sufficiently large dataset to define the spatial variability of the large areas associated with mine site reclamation. The objectives of this study were: (1) to compare the K-s estimated from air permeability measurements with those measured using a GP and (2) to use air permeability measurements to characterize spatial variations of K-s for two reclamation sites, one on a lean oil sands dump at the Aurora oil sands mine in Northern Alberta, and a second on a waste rock storage area at the Key Lake Uranium Mine in Northern Saskatchewan. The results indicated that the K-s values estimated from air permeability measurements were similar to,those measured using a GP if the air permeability measurements were adjusted for differences between in situ water contents and field capacity water contents. The probability distributions of K-s values obtained from both measurement methods were also found to be similar at a 0.01 level of confidence. Geostatistical analysis revealed a weak spatial dependency in K-s values, with an effective range of 158 m for the Aurora site and a non-significant spatial structure for Ks at the Key Lake mine site. This paper provides a practical example of how air permeability measurements combined with a limited program of GP testing can be used to characterize spatial variability of K-s on reclamation soils. (C) 2015 Elsevier B.V. All rights reserved.