(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: | https://publications.iowa.gov/id/eprint/17140 |