ABSTRACT
The compression behaviour of soils has always been a topic of investigation in geotechnical engineering because many field problems are analyzed solely on the basis of soil properties obtained from compression tests. For example, the great majority of settlement calculations for geotechnical structures is made based on the coefficient of compressibility of the soil layers beneath the foundations (Butterfield & Baligh 1996). Modelling the compression behaviour of soils is, in reality, very complicated because of the wide ranges involved in two major variables of the materials found or used in the engineering practice. One is the variation in material composition, i.e., grain size and mineralogy. The other is the variation in the structure of the soils, i.e., the arrangement and bonding of the constituents. Structure is defined here in a very broad sense in that it encompasses all features of a soil that are different from those of the material with the same mineralogy at a selected reference state. Therefore, the structure of soil and its influence, as defined in this paper, are relative quantities and depend on the selected reference state. The removal of geomaterial structure is commonly referred to as destructuring. The destructuring due to stress excursions is usually an irrecoverable and progressive process. A study of the compression behaviour of clays with natural structures and with artificially treated structures is made in this paper, and the behaviour of soils in reconstituted states is adopted as the reference state behaviour.
