Improving Subgrade Support Values with Longitudinal Drains, MLR-84-3, 1984

(1984) Improving Subgrade Support Values with Longitudinal Drains, MLR-84-3, 1984. Transportation, Department of

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Abstract

This report is a brief summary of research on the effect of longitudinal drains on subgrade support. The Iowa DOT began installing longitudinal subdrains at a depth of 24" in 1978. The trend in Iowa has been to deeper longitudinal drains with the present standard being 48" deep. A very limited amount of data would indicate that the deeper longitudinal drains are providing a greater benefit to the subgrade support value. The 24# deep drains of the Poweshiek Interstate 80 project yielded a spring subgrade support value of 165. The 30" deep drains on Pottawattamie Interstate 80 yielded a K value of 170 while the 48"deep drains on Cass County Interstate 80 yielded a K value of 210. This limited amount of data would indicate that the deeper drains provide greater benefit to improvement of the subgrade support values.

Item Type: Departmental Report
Keywords: Drains, Subgrade (Pavements), Longitudinal, Supports
Subjects: Transportation > Pavements
Transportation
Transportation > Roads and highways
Transportation > Research
Transportation > Design and Construction
Transportation > Data and Information Technology
ID Code: 17140
Deposited By: Iowa DOT Library
Deposited On: 09 Jun 2014 12:27
Last Modified: 15 Jan 2015 12:41
URI: http://publications.iowa.gov/id/eprint/17140