Freeze-Thaw Effects on Clay Covers and Liners

Chamberlain, E. J.; Ayorinde, O. A.; ,

Freeze-Thaw Effects on Clay Covers and Liners

by E. J. Chamberlain, U.S. Army Cold Regions Research and, Engineering Lab, Hanover, United States,
O. A. Ayorinde, U.S. Army Cold Regions Research and, Engineering Lab, Hanover, United States,

Document Type: Proceeding Paper

Part of: Cold Regions Engineering

Abstract:

The properties of clay covers and liners used for containing solid waste materials are highly susceptible to environmental stresses. Even when clay layers are protected from drying, freezing and thawing can cause them to shrink and crack. The resulting increase in permeability can cause failure of a cover or liner to limit the leakage of pollutants to an acceptable value. Laboratory tests indicate that freezing and thawing can cause permeability increases of two orders of magnitude or more, yet its effects in the field are neither well known nor very predictable. The major design options are to prevent freezing and to cover the clay layer with an impermeable membrane. This report reviews laboratory experiments on the effects of freezing and thawing on the permeability of clayey soils and develops compaction requirements to minimize damage to clay layers caused by freezing and thawing. Permeability increases greater than two orders of magnitude have been observed. The smallest changes in permeability occurred when the soils were compacted to high densities. We show how a relationship between the percent increase in permeability and the liquidity index of the soil affects the acceptable range of moisture contents and densities required for compaction. A simple method for estimating the acceptable zone based on the plastic limit and the degree of saturation is also provided.

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