ABSTRACT
This chapter describes the physical basis of the phenomenological model, proposing a stochastic process as the physical basis for the earlier model and its parameters. This physical model, when applied to 130 shear tests from various research programs on uncemented clays, silts, sands and mixtures thereof, under a variety of test conditions, closely fit the data together with an orderly variation of the model parameters. The chapter adheres to the correct definition of the steady state in particles from Poulos (1981): The steady-state of deformation for any mass of particles is that state in which the mass is continuously deforming at constant volume, constant normal effective stress, constant shear stress, and constant velocity. It also describes a stochastic, micro-structural model based on the simple principle that particles move into the steady-state structure at random shear strains. The chapter extends the phenomenological model by giving it its physical basis.
