Collapsible soils in Louisiana.

Arman, Ara; Thornton, Samuel I.

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Collapsible soils in Louisiana.

1972-01-01
By Arman, Ara ; Thornton, Samuel I.

File Language:

English

Details

Creators:

Arman, Ara ; Thornton, Samuel I.
Corporate Creators:

Louisiana State University (Baton Rouge, La.)
Corporate Contributors:

Louisiana. Dept. of Transportation and Development ; United States. Federal Highway Administration
Subject/TRT Terms:

Collapsible Soils Loess Organic Silts Pimple Mounds Silts Soil Stability Soil Stabilization Soil Tests Test Procedures
Publication/ Report Number:

Bulletin No. 111
Resource Type:

Tech Report
Geographical Coverage:

Louisiana
Corporate Publisher:

Louisiana State University, Baton Rouge
Abstract:

In southwest Louisiana, some surface silts (up to 3 feet deep) collapse under load after moisture is added. These soils were indistinguishable from nearby normal silts through routine tests. The deposits occur as low, gently-sloping ridges. Very similar collapsible soils were found in the well-known pimple mounds of the area. In the stable silts, vermiculite is the dominant clay mineral; in the collapsible silts, montmorillonite, Kaoline and illite are also present. Moisture is held in the pores of collapsible silts by electro-chemical forces. When collapsible silts were remolded with water or ethylene glycol (both polar liquids), no water passed through under 2 meters of head. In settled mixtures of collapsible silts and a solution of Calgon, (commercial brand of Sodium Hexameta phosphate) the supernatant liquid was black. The color change is attributed to lignins. Four criteria were established for identifying collapsible silts: an in-place unit weight less than 80 lbs/cu ft; a maximum dry unit weight less than 104 lbs/cu ft; a black liquid after the soil solids have settled out in a 3% solution of Calgon; and a total strain of at least 15% in the collapse test (a modified consolidation test of an oven-dried, undisturbed sample that is then saturated under pressure to 16 tons/sq ft).
Format:

PDF
Funding:

State Project No. 736-01-25 ; Research Project No. 68-8S
Collection(s):

US Transportation Collection
Main Document Checksum:

urn:sha256:f808636f256e6576b7196e9f596ba19c0de0e2dbf0c7402e25be19449964a44f
Download URL:

https://rosap.ntl.bts.gov/view/dot/22000/dot_22000_DS1.pdf
File Type:

[PDF - 3.97 MB ]

File Language:

English

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