Analytical theory for one-dimensional consolidation of clayey soils exhibiting rheological characteristics under time-dependent loading

This paper presents analytical solutions to the one-dimensional consolidation problem taking into consideration the rheological properties of clayey soil under variable loadings. A four-element rheological model is introduced, and different loading types are involved, i.e. constant loading, one-step loading, triangular loading, rectangular loading,, and isosceles-trapezoidal cyclic loading. The differential equations governing consolidation are solved by the Laplace transform. Based on the solutions obtained, the influences of the rheological parameters and loading conditions on the consolidation process are investigated. It has been shown that the consolidation behavior is mainly governed by four dimensionless parameters, a(1), a(2), b, and TO. Load shape has a great influence on the rate of consolidation. A decrease either in the modulus of the spring in the Kelvin body or in the viscosity coefficient of independent dashpot will slow down the rate of consolidation. An increase in the viscosity coefficient of the dashpot in the Kelvin body will make the rate of consolidation increase at an early stage but decrease at a later stage. For isosceles-trapezoidal cyclic loading, the consolidation rate in each cycle reaches a maximum at the end of the constant loading phase and the minimum at the end of this cycle. Copyright (C) 2008 John Wiley & Sons, Ltd.