Cyclic Characterization of Liquefiable Sands

Application of a Hill-Climbing technique to the formulation of a new cyclic nonlinear elastic constitutive model

“…In this paper, a random mutation Hill-Climbing optimisation technique [7] was employed in order to improve the global accuracy of a cyclic nonlinear elastic model based on that proposed by Matasovic and Vucetic [5].…”

“…The first of these aspects, as previously mentioned, describes the nonlinear stress-strain behaviour exhibited by the material during initial loading and may assume a wide variety of forms, as illustrated by the numerous equations found in the literature (e.g. [1,5,[13][14][15]). In terms of the second component of the model, Masing [16] established two basic rules, which define the response of the material during unloading/reloading situations: (I) for initial loading, the stress-strain behaviour of the material is defined by the selected backbone function; (II) if a strain reversal occurs at a given point, the stress-strain behaviour of the material follows the backbone function with its origin translated to this point and scaled by a factor of 2.…”

“…Vucetic [5], it is important to note that the latter is intended for the calculation of the secant shear modulus, rather than allowing the direct quantification of the tangent stiffness value. Therefore, to compute the variations of the secant stiffness and damping ratio with deformation level, a numerical procedure is necessary to integrate Eq.…”

“…Therefore, it is perhaps unsurprising that, in order to mitigate the effect of the abovementioned limitation of the cyclic nonlinear elastic framework, two distinct kinds of solution have been proposed: (a) improving the flexibility of the backbone function by introducing additional parameters [1,5], and (b) altering the rules governing the response simulated during unloading/reloading stages [2,6]. In this paper, the latter approach is converted into the analysis of an optimisation problem, where the objective is to determine the unloading/reloading behaviour which results in the most accurate reproduction of a given variation of damping ratio with strain amplitude.…”

Numerical investigation of the response of the Yele rockfill dam during the 2008 Wenchuan earthquake

“…The model was developed based on the hyperbolic model by Kondner and Zelasko (1963) and the modified hyperbolic model by Matasovic & Vucetic (1993), but involves complex rules to account for some complicated aspects of soil behaviour, such as the independent simulation of shear and volumetric deformation mechanism, spatial variation of soil stiffness and adequate simulation of material damping at very small strain levels. The backbone curve for the ICG3S model is expressed by the integration of Equation (1) (2) and (3) (Potts and Zdravković, 1999), are employed to derive the formulation of the backbone curve.…”