Characterising Undrained Monotonic Behaviour of Saturated Sand

The characterisation of undrained residual shear strength of silty sand is described within the framework of a steady state concept. The fundamental aspects of soil behaviour during monotonic loading are illustrated using laboratory triaxial test results. The steady state line, phase transformation line, initial dividing line, initial state ratio are introduced to characterise the undrained residual shear strength of silty sand. The importance of defining the undrained residual shear strength ratio with respect to the effective major stress, usually the effective overburden stress is illustrated.