Abstract
This paper aims to extend the first author's method for simulating the time dependent stress-strain behavior of isotropically consolidated clays, taking into account the various time effects in the anisotropically K0-consolidated clays. The fundamental postulate in the method is that the stresses and strains in soils behave themselves in a way of minimizing the whole dissipated energy within the limitations required by several constraints, i. e. the equations of equilibrium, the experimental relationship between the stresses and volume change, and so on. By the use of an additional assumption concerning the time dependency of dilatancy, the method provides a unified representation of various time effects such as the constant strain rate shear, stress relaxation and creep processes. In order to extend the method to the shear of the K0-consolidated clays, this paper adopts some new devices, for instance, the plotting system of stress trajectory which enables to apply the energy equation in the original Cam Clay model to the extension tests without any modification. Such devices may lead to disclose the mechanical framework of the existing constitutive models. Based on these devices it is shown that the proposed method can appropriately describe a wide variety of time effects both in the triaxial compression and extension tests of K0-consolidated clays. The stress-strain response predicted by the method shows a fairly good agreement with the measured results. Through the development and application of the method, many important properties in the undrained shear of K0-consolidated clays are clarified from the physical viewpoint.
