THE EXPANSIVE SOIL PROBLEM ON SUBGRADES OF PAVEMENTS AND STRUCTURES FOR ROADS AND AIRFIELDS
RESEARCH WAS CONDUCTED ON THE PROBLEMS OF EXPANSIVE SUBGRADE SOILS WHICH CONSISTS OF: (1) THE STATE OF THE ART ON EXPANSIVE SOILS, (2) A FAIRLY DETAILED STATEMENT OF THE PROBLEMS ON EXPANSIVE SOILS, THEIR RELATIVE PRIORITY, AND (3) AN EXTENSIVE BIBLIOGRAPHY IS PRESENTED GIVING TITLE AND REFERENCES WHERE INFORMATION ON THE VARIOUS SUBJECTS CAN BE FOUND. THE EXPANSIVE SOILS ANALYZED ARE THE MANY CLAY SHALE SOILS IN THEIR NATURAL STATE WHICH SWELL DUE TO RELEASE OF LOAD AS IN DEEP EXCAVATIONS. MANY OF THEM CONTAIN MONTMORILLONITE TO VARYING DEGREES AND SWELLING WILL CONTINUE AND CANNOT BE ACCURATELY PREDICTED BY THE CONSOLIDATION TEST. THESE SOILS EVEN SHRINK DETRIMENTALLY AND QUITE OFTEN HAVE A HIGH COLLOIDAL CONTENT. THE PERMEABILITY IS VERY LOW EXCEPT WHEN THE SOIL IS DRY AND CRACKED AND WATER CAN PASS THROUGH THE OPEN CRACKS. SUCH EXPANSIVE SOILS ARE USUALLY HIGHLY SLICKEN-SIDED. A NEGATIVE PORE PRESSURE LAYER MAY DEVELOP OVER BROAD AREAS AND HAVE A FREE WATER TABLE ABOVE IT. EQUILIBRIA AND MOISTURE CHANGES IN SOILS BENEATH COVERED AREAS ARE DISCUSSED WITH ENGINEERING EFFECTS OF MOISTURE CHANGES IN SOIL. THE GENERAL ITEMS OF RESEARCH CONDUCTED ON SOIL EXPANSION ARE REVIEWED. THE FOLLOWING-PRIORITY STUDIES ARE NEEDED: (1) CORRELATION OF LABORATORY AND IN-SITU SUCTION PRESSURES WITH PROTOTYPE BEHAVIOR, OR LARGE SCALE FIELD TEST SECTIONS, (2) MORE STUDIES WITH DESIGNED AND INSTRUMENTED PROTOTYPE STRUCTURES OR FIELD TEST SECTIONS, (3) INTENSIVE STUDY OF PROBABLE ENVIRONMENT CHANGES INDUCED BY CONSTRUCTION TECHNIQUES AND PROCEDURES, (4) COMMUNICATION BETWEEN THE SOIL SCIENTIST AND RESEARCHER AND SOILS ENGINEER INVOLVED IN DESIGN, SPECIFICATION AND CONSTRUCTION NEEDS, (5) PREDICTION OF MOISTURE AND HEAVE TO IMPROVE FOUNDATION AND DESIGN IN THE SELECTION OF THE PROPER FOUNDATION FOR THE STRUCTURE IN QUESTION, (6) IMPROVEMENT IS NEEDED IN STABILIZING SUBGRADES BENEATH PAVEMENTS AND CANAL LININGS, AND (7) A COMMITTEE SHOULD BE ASSIGNED BY THE INTERNATIONAL SOIL MECHANICS AND FOUNDATION ENGINEER ORGANIZATION TO STUDY AND MINIMIZE LEGAL DIFFICULTIES FACING THE SOIL MECHANICS ENGINEER.
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Supplemental Notes:
- Vol 6, No 21, PP 18-21, 25-27, 43-50, PHOTS, 168 REF
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Authors:
- Turnbull, W J
- Publication Date: 1969
Media Info
Subject/Index Terms
- TRT Terms: Airport runways; Chemical analysis; Clay; Moisture content; Montmorillonite; Pavements; Permeability; Pore pressure; Shale; Shrinkage; Soil chemistry; Soil mechanics; Soils; Subgrade (Pavements); Subgrade materials; Swelling soils
- Old TRIS Terms: Highway pavement; Negative pore pressures; Soil analysis; Soil permeability; Soil shrinkage
- Subject Areas: Geotechnology; Highways; Pavements;
Filing Info
- Accession Number: 00232935
- Record Type: Publication
- Files: TRIS
- Created Date: Oct 5 1970 12:00AM