Location

St. Louis, Missouri

Session Start Date

6-1-1993

Abstract

Loess, which consists predominantly of low plasticity to non-plastic silt (PI≤10) with varying amounts of sand and clay-sized (- 5 microns) material, covers much of north-central Oregon and eastern Washington. Several landfills operate in this area. Because of the lack of clayey soils and clayey bedrock in the region, loess was proposed for use as the low permeability soil barrier layer. Laboratory testing and large-scale field tests of test fills using SDRI's have shown that the remolded permeability of the loess is related to grain-size, soil gradation, and the percent saturation of the placed soil. We had an approximately 1:1 correlation between the permeability results of laboratory remolded samples, undisturbed Shelby tube samples of test fills, and field SDRI tests. Data from six different sites have consistently shown that in order to achieve a permeability of less than 1x10-6 cm/s, the loess must contain greater than 70 percent minus U.S. No. 200 sieve and have at least 15 percent minus 5 microns material. In addition, the loess must be placed at a minimum of 2 percent over standard Proctor optimum moisture content and be compacted to a dry density which corresponds to a minimum of 85 percent saturation at the measured moisture content.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Third Conference

Publisher

University of Missouri--Rolla

Publication Date

6-1-1993

Document Version

Final Version

Rights

© 1993 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Use of Low Plasticity for Soil Liners and Covers

St. Louis, Missouri

Loess, which consists predominantly of low plasticity to non-plastic silt (PI≤10) with varying amounts of sand and clay-sized (- 5 microns) material, covers much of north-central Oregon and eastern Washington. Several landfills operate in this area. Because of the lack of clayey soils and clayey bedrock in the region, loess was proposed for use as the low permeability soil barrier layer. Laboratory testing and large-scale field tests of test fills using SDRI's have shown that the remolded permeability of the loess is related to grain-size, soil gradation, and the percent saturation of the placed soil. We had an approximately 1:1 correlation between the permeability results of laboratory remolded samples, undisturbed Shelby tube samples of test fills, and field SDRI tests. Data from six different sites have consistently shown that in order to achieve a permeability of less than 1x10-6 cm/s, the loess must contain greater than 70 percent minus U.S. No. 200 sieve and have at least 15 percent minus 5 microns material. In addition, the loess must be placed at a minimum of 2 percent over standard Proctor optimum moisture content and be compacted to a dry density which corresponds to a minimum of 85 percent saturation at the measured moisture content.