Minimum Thickness of Compacted Soil Liners: I. Stochastic Models

Abstract

Regulatory agencies often specify a minimum thickness of compacted soil liners that will ensure that the liner performs adequately. No consensus has been formed, however, on an appropriate minimum thickness. In some states soil liners may be as thin as 60 cm (2 ft), whereas in other states soil liners are required to be at least 360 cm (12 ft) thick. Difficulties encountered in the analysis of soil liners, such as uncertainties in construction, flow in macropores, and spatial variability of hydraulic properties, and variability in past experiences of regulatory agencies are the most likely reasons for the lack of consensus on minimum thickness. In the present paper, the first in a two‐part series, two models of fluid flow in compacted soil liners are described. These models incorporate flow in macropores, spatial variability, and uncertainty via probability theory, but only consider advective transport in saturated soil. In the second paper, the models are used to identify an appropriate minimum thickness of soil liners.