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Title:

IDENTIFICATION OF COLLAPSIBLE SOILS IN LOUISIANA

Accession Number:

00230233

Record Type:

Component

Availability:

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Order URL: http://worldcat.org/isbn/0309021553

Abstract:

IN SOUTHWEST LOUISIANA, EXPERIENCE WITH WIDESPREAD SURFACE DEPOSITS (AS THICK AS 5 FT) FOR USE IN EARTH STRUCTURES HAS SHOWN THAT SOME SOILS CAN WITHSTAND THE DESIGN LOAD, BUT OTHERS EXHIBIT CHARACTERISTICS OF A COLLAPSIBLE SOIL IN THE PRESENCE OF LOAD AND MOISTURE. ALL OF THESE SOILS ARE CLASSIFIED AS SILT; THE COLLAPSIBLE SOILS CANNOT BE DISTINGUISHED FROM NORMAL SILTS BY USING ROUTINE TESTS. THE KNOWN AND CONJECTURED AREAS CONTAINING COLLAPSIBLE SILTS FALL WITHIN A 30- MILE BAND THROUGH THE COASTAL PRAIRIE TERRACE, THE MISSISSIPPI RIVER TERRACES, AND THE LOESSIAL HILLS. THE DOMINANT CLAY MINERAL IN THE COLLAPSIBLE SILTS IS MONTMORILLONITE; KAOLINITE AND ILLITE ARE ALSO PRESENT. THESE SILTS ATTRACT AND SUSPEND MOISTURE IN THEIR PORES BY ELECTROCHEMICAL FORCES. THEY BECOME VIRTUALLY IMPERMEABLE WHEN A POLAR LIQUID, SUCH AS WATER OR ETHYLENE GLYCOL, IS ADDED. IF A COLLAPSIBLE SILT IS MIXED IN A SOLUTION OF SODIUM HEXAMAETAPHOSPHATE (CALGON) AND ALLOWED TO SETTLE, THE LIQUID TURNS BLACK. THIS COLOR CHANGE IS ATTRIBUTED TO LIGNIN. ALONG WITH A DETERMINATION OF THE PRESENCE AND LOCATION OF COLLAPSIBLE SOILS IN LOUISIANA, CRITERIA FOR DISTINGUISHING THESE SOILS FROM NORMAL SILTS ARE ESTABLISHED. WHEN TWO OF THE FOLLOWING FOUR CONDITIONS ARE MET, THESE SOILS MAY BE CONSIDERED COLLAPSIBLE: IN SITU UNIT WEIGHT OF THE UNDISTURBED SILT IS LESS THAN 80 LB CUBE FT; MAXIMUM DRY DENSITY IS LESS THAN 104 LB CUBE FT; AFTER THE SOLIDS OF THE SUSPECTED SOIL HAVE SETTLED OUT IN A 3 PERCENT SOLUTION OF SODIUM HEXAMETAPHOSPHATE (USED IN ROUTINE HYDROMETER ANALYSES), THE SUPERNATANT LIQUID IS BLACK; AND A TOTAL STRAIN OF AT LEAST 15 PERCENT OCCURS AT THE END OF THE 16-TSF LOADING IN A COLLAPSE TEST. /AUTHOR/

Supplemental Notes:

Sponsored by Committee on Exploration and Classification of Earth Materials. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.

Monograph Title:

Soil classification

Monograph Accession #:

01410342

Authors:

Arman, Ara
Thornton, Samuel I

Pagination:

pp 14-22

Publication Date:

1973

Serial:

Highway Research Record

Issue Number: 426
Publisher: Highway Research Board

Conference:

52nd Annual Meeting of the Highway Research Board

Location: Washington District of Columbia, United States
Date: 1973-1-22 to 1973-1-26

ISBN:

0309021553

Media Type:

Digital/other

Features:

Figures (6) ; References (10) ; Tables (2)

Uncontrolled Terms:

Criteria

Geographic Terms:

Louisiana

Old TRIS Terms:

Louisiana

Subject Areas:

Geotechnology; Highways

Files:

TRIS, TRB

Created Date:

Aug 20 1973 12:00AM

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