Coefficient of Consolidation by Inflection Point Method

The coefficient of consolidation in the Terzaghi theory of consolidation has been commonly determined by fitting the theory to observed compression with time in an incremental loading oedometer test. The Terzaghi theory is applicable to compression and swelling. A similar coefficient governed by horizontal permeability is used in the Barron formulation of consolidation with vertical drains. The most widely used graphical methods of Casagrande and Taylor, which fit the theory to observed data at 50 and 90% primary compression, respectively, are rather laborious. The inflection point method requires only a visual identification of the inflection point on the compression versus log time curve. The values of coefficients of consolidation by the simple inflection point method are quite similar to those from the Casagrande method.