Abstract:
AN ANALYSIS IS MADE OF THE PROBLEMS INVOLVED IN A STUDY OF SUBGRADE SOILS. SOIL IS NOT A SIMPLE MATERIAL SUCH AS ENGINEERS ARE ACCUSTOMED TO, BUT IS A CONSTANTLY CHANGING ORGANISM WHOSE PROPERTIES CANNOT BE UNDERSTOOD UNLESS TRACED BACK TO THEIR BASIC PHYSICAL ORIGIN. ONE OF THE MOST OUTSTANDING PROBLEMS IN ROAD SOIL INVESTIGATION CONSISTS IN DEVELOPING A SCIENTIFIC THEORY OF TOP SOIL BEHAVIOR. THE ESSENTIAL COMPONENTS OF THE PROBLEM ARE DISCUSSED INDIVIDUALLY, THEIR PHYSICAL NATURES ARE EXPLAINED AND THE GAPS IN EXISTING KNOWLEDGE POINTED OUT. THE CHANGES IN VOLUME DUE TO WETTING AND DRYING AND TO FREEZING AND THAWING ARE IMPORTANT FACTORS WITH RESPECT TO ROAD WORK, AS IS ALSO THE LAG EXHIBITED BY SOIL IN ITS REACTION TO PRESSURE. IT IS NOT POSSIBLE BY APPLIED MECHANICS TO COMPUTE STRESSES, BEARING CAPACITY, VOLUME CHANGES AND OTHER PROPERTIES OF SOIL. THE STUDY MUST BE MADE BY DETERMINING INDIVIDUALLY THE SERIES OF FUNDAMENTAL FACTS, AND THEN RELATING THEM TO EACH OTHER, MUCH IN THE MANNER THAT PHYSIOLOGISTS MUST USE IN STUDYING LIVING ORGANISMS. THERE SEEMS TO EXIST ONLY ONE METHOD FOR INVESTIGATING THE EFFECT OF ARTIFICIAL SUBGRADE IMPROVEMENT. FIRST STUDY THE EFFECT OF THE REMEDIAL MEASURE BY OBSERVATION IN THE FIELD. THEN WORK OUT AN EXPLANATORY HYPOTHESIS, AND FINALLY PLAN A LABORATORY TEST TO CHECK THE HYPOTHESIS.
Supplemental Notes:
Vol 6, pp 394-408, 2 FIG. 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.
