Relationship between Volume and Moisture Content of Soils Behavior of soil in the field of centrifugal force (I)

• Published in: Transactions of The Japanese Society of Irrigation, Drainage and Reclamation Engineering Vol. 1988; no. 138; pp. 37 - 44,a1
• Main Authors: SAKURAI, Yuji, SATOH, Koichi
• Format: Journal Article
• Language: Japanese
• Published: The Japanese Society of Irrigation, Drainage and Rural Engineering 25.12.1988
• ISSN: 0387-2335; 1884-7234
• DOI: 10.11408/jsidre1965.1988.138_37

The change in volume and moisture content of soils in the field of centrifugal force, where soils are subject to actions of dehydration and loading at the same time, are discussed compared with the change obtained by two methods: airdrying (or “non-loading method”) and standard consolida tion test, for five kinds of clayey soils with different conditions of their geneses, and for the parts of soil sample far from free-water table in the centrifugal tube. The relationship between volume and moisture content of soils was classified into three types (I, II, and III). The types I, III, and II show no volume change (ΔV=0) with change in moisture content, the same quantity in change of volume as that of moisture content (ΔV=ΔV), and intermediate in behavior between I and III (ΔV<ΔVw), respectively. Type II or III appeared in the moisture range from saturation to about pF 4. 2 for the five claye clayey samples made of disturbed soils in the field of centrifugal force. However, type I appeared in a range of low centrifugal force, where the soils was high in moisture content, for compacted soils still having well developed structure. The relationship between volume and moisture content changed in strength of the actions and rigidity in soil matrix and fabric of the sample. The relationship between volume and moisture content was dependent on the distance from boundary (reference surface) for the sample with 5 cm length in centrifugal tube. The upper parts of sample in the tube, which were nearer to center of rotation, had the type II. That type were similar to that by non-loading method (suction and pressure plate methods, etc.). The lower parts of sample had the type III. That type were similar to that by consolidation test for the saturated sample. The two types of the relation correspond to two fundamental mechanisms, which determines state in volume and moisture content in case of soils subject to actions of dehydration and/or loading. Rigidity of soil structure and formation of meniscus respond to the actions, which corresponds to type I. Access of soil particles to each other responds to the actions, which corresponds to type III. Type II is the mixture of two mechanisms. It is pointed out that states in volume and moisture content of soil resulted from behavoir of soilbased on the two mechanisms. The responding mechanisms are so as simultaneously to adjust a mechanical balance in soil system and a potential balance of soil water under the actions of dehydration and loading. This way of thinking can give the state a comprehensive explanation.