Civil Engineering Association

Laing Barden - Consolidation of Clay With Non-linear Viscosity

Consideration of the assumptions made in Terzaghi's theory of consolidation indicates that a main source of error is in the assumed rheological behaviour of the soil skeleton. Based on the Terzaghi-Taylor concept of secondary consolidation a more natural non-linear rheological model is proposed and an approximate finite difference solution obtained using a digital computer. This solution, obtained in dimensionless form, emphasizcs the continuous nature of the consolidation process and indicates errors involved in arbitrary divisions into primary and secondary stages. The amount of secondary compression is shown to be strongly dependent on the thickness of the sample and on the pressure increment ratio, but the solution provides a simple method of accounting for this in the extrapolation of settlementtime data obtained in laboratory tests to the field scale.