Energy-based analysis of permanent strain behaviour of cohesive soil under cyclic loading

Abstract

In this paper the original results of uniaxial cyclic compression test on cohesive soil are presented. The shakedown phenomena in cohesive soil are described. Energy-based method highlights the change of soil material behaviour from plastic shakedown through plastic creep shakedown to incremental collapse. The samples were cyclically loaded under undrained conditions with the constant amplitude of stress in one-way test procedure. In this study the energy-based method was presented as a proper method to categorise response of cohesive soil to cyclic loading in uniaxial conditions. A shakedown criterion factor, S E , was introduced to help understand the shakedown phenomena in cohesive soil. In cohesive soils the absence of a limit between plastic shakedown and plastic creep shakedown was pointed out.

Long-Term Cyclic Loading Impact on the Creep Deformation Mechanism in Cohesive Materials

“…The most important limit is between the deformation behaviors, i.e., which will lead to failure and which will be safe for the construction. The most recent deformation category is the shakedown concept [ 14 , 15 , 16 , 17 ], first applied to the categorization of unbound granular materials deformation [ 18 , 19 , 20 , 21 ]. The shakedown concept states that the plastic deformation during long-term cyclic loading cases can fail, creep, or shakedown, where the plastic strain rate decreases, and finally, the material achieves an elastic response.…”

“…This idea is part of the shakedown theory where the stress state above shakedown limit is called the plastic cyclic creep zone in which the soil develops plastic strain and where the increment per cycle decreases almost to a constant level [ 32 ]. Nevertheless, an additional plastic strain can occur between a few cycles where no plastic strains are observed, primarily in undrained conditions [ 9 , 16 , 33 ]. This behavior shows that the cohesive material in undrained conditions remains in an instability state, and failure of the structure is dependent only on the stress state imposed on the soil structure.…”

Locating Critical Circular and Unconstrained Failure Surface in Slope Stability Analysis with Tailored Genetic Algorithm

“…The determination of the potential slip surface becomes particularly important in the vicinity of infrastructure, development housing, or when an embankment protects flood plains. The focus in the majority of cases is on determining the geotechnical parameters for calculations [18], [21] but, as studies presented in this article show, the right location of potential slip curves significantly affects the factor of safety (Fs).…”