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FACTORS CONTROLLING MINIMUM SOIL LINER THICKNESS
Citation:
Anderson, D., M. Lupo, J. Rehage, J. Sai, R. Shiver, R. Speake, K. Brown, AND D. Daniel. FACTORS CONTROLLING MINIMUM SOIL LINER THICKNESS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/2-91/008.
Description:
This report describes a three-part study to gather information on liquid flow through soil liners in hazardous waste disposal facilities. n the first part of the study a model was developed to simulate flow occurring through discreet channels in lifts (a layer of compacted soil) and in the horizontal layer between lifts. he model indicated that high overall field hydraulic conductivity values may result from horizontal flow between lifts. In the second part of the study, laboratory tests using large 60-cm-diameter permeameters showed that the conductivity to water typically increased by one order of magnitude with depth in a 23-cm-thick lift of compacted clay. Clod sizes ranging from 2.5 to 7.5-cm had little influence on the hydraulic conductivity. Exposure of the compacted soil to the atmosphere for as little as 24 hr resulted in severe cracking and associated high conductivities resulting from flow through the desiccation cracks. ulk density was a poor predictor of the conductivity of a compacted soil. ye patterns in the permeameters also indicated flow through preferential channels and inter-clod spaces. In the third part, field studies of a 3-lift liner revealed that horizontal flow does indeed occur at the interface between the lifts when channels penetrate the overlying lift.