PORE PRESSURES IN BASE COURSE
ALTHOUGH IT IS DESIRABLE TO KEEP BASE COURSES DRY, THEY USUALLY GET WET IN SPITE OF EFFORTS TO PREVENT ENTRANCE OF WATER OR PROVIDE DRAINAGE. HOWEVER, THE STABILITY OF GRANULAR MATERIAL DEPENDS MORE ON THE STATE OF STRESS IN THE PORE WATER THAN ON THE AMOUNT OF WATER PRESENT. A LOAD APPLIED TO WET SOIL (TOTAL PRESSURE) IS CARRIED BETWEEN THE SOIL GRAINS (INTERGRANULAR PRESSURE) OR ON THE WATER (PORE PRESSURE). SINCE THE STRENGTH OF SOIL DEPENDS UPON THE INTERGRANULAR PRESSURE, ANY PORE PRESSURE REDUCES THE STRENGTH BECAUSE THE INTERGRANULAR PRESSURE EQUALS THE TOTAL PRESSURE MINUS THE PORE PRESSURE. THEREFORE, MEASURES WHICH PREVENT THE DEVELOPMENT OF PORE PRESSURES MAY MAINTAIN THE STABILITY OF A BASE COURSE EVEN THOUGH THE MATERIAL STAYS WET. THIS REQUIRES MINIMIZING THE AMOUNT OF FINES WITHOUT MAKING A MATERIAL TOO HARSH TO PLACE WITH A UNIFORM HIGH DENSITY. FURTHER RESEARCH IS REQUIRED TO DEVELOP MORE REFINED DESIGN CRITERIA FOR BASE COURSES. THIS SHOULD INCLUDE THE THICKNESS, WIDTH, AND SLOPE OF BASE COURSES, THE PERMEABILITY, CAPILLARITY, STRENGTH AND STRESS-STRAIN RELATIONS OF BASE COURSE MATERIALS, AS WELL AS THE AMBIENT CONDITIONS OF MOISTURE AND TEMPERATURE. /AUTHOR/
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Supplemental Notes:
- Vol 37, pp 468-492, 18 FIG, 4 TAB, 17 REF. 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.
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Authors:
- Barber, E S
- Steffens, G P
- Publication Date: 1958
Media Info
- Media Type: Digital/other
- Monograph Title: Proceedings of the Thirty-Seventh Annual Meeting of the Highway Research Board, Washington, D.C., January 6-10, 1958
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Serial:
- Highway Research Board Proceedings
- Volume: 37
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Base course (Pavements); Moisture content; Pore pressure; Soils; Strength of materials
- Subject Areas: Geotechnology; Highways;
Filing Info
- Accession Number: 00236042
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Oct 18 1971 12:00AM