Terzaghi's theory of consolidation, and the discovery of effective stress: C. R. I. Clayton, H. Muller Steinhagen & W. Powrie, Proceedings - ICE: Geotechnical Engineering, 113(4), 1995, pp 191–205

Abstract

This paper provides a modern commentary on Terzaghi's theory of consolidation in soil mechanics, and includes an English translation of his 1923 paper A Method of Calculating the Permeability of Clay from the Variation of Hydrodynamic Stress with Time. The paper has four parts: (1) introduction; (2) a historical description of Terzaghi's work; (3) the English version of Terzaghi's paper; and (4) an extensive mathematical commentary on Terzaghi's paper. The discovery of the principle of effective stress marks the beginning of modern soil mechanics, and was closely linked to Terzaghi's experimental work on the behaviour of clays. Terzaghi's paper acted as a catalyst, which led to soil mechanics and then geotechnical engineering becoming branches of civil engineering. It gives the first statement of the classical theory of consolidation, in which the concepts of core pressure and effective stress are fundamental. It formulates a partial differential equation for the flow of water through clay, with suitable boundary conditions, which is analogous to the heat conduction equation. It then calculates the permeability from the adiabatic change of state.