Effect of Soil Plasticity on Cyclic Response

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

“…Indeed, the obtained curves agreed well with the previously computed discrete variations in the -plane, leading to the accurate simulation of the selected empirical data, thus validating the followed approach and, more specifically, the expression adopted for the modified scaling factor. Lastly, the performance of the formulated constitutive relationship was further established by showing that a considerable number of different empirical damping ratio curves found in the literature [8][9][10] could be reproduced with a substantial degree of accuracy (i.e. average relative errors below 5 %).…”

“…Indeed, in addition to the behaviour predicted by the expressions proposed by Darendeli [10] for distinct combinations of mean effective stress ( = 100 kPa and 500 kPa) and plasticity index ( = 0%, 15%, 30% and 50%), the curves presented by Vucetic and Dobry [8] for materials of various levels of plasticity and by Rollins et al [9] for gravelly soils were employed in the calibration of the required parameters. This was accomplished by adopting a two-stage procedure, according to which the original model quantities ( , and ) were firstly assessed based on the selected stiffness degradation curve, followed by the application of the previously described Hill-Climbing algorithm to determine the values of , , , and using the variations of damping ratio as reference data.…”

“…The performance of the proposed model is evaluated by calibrating the respective parameters based on empirical damping ratio curves [8][9][10] and assessing the corresponding average relative error.…”

Axial Non-linear Dynamic Soil-Pile Interaction - Keynote

“…To aid practical applications, Michaelides et al ([22], [23]) utilized experimental data (e.g. Vucetic & Dobry [8]) characterizing the dependence of the secant shear modulus and hysteretic damping of soil on the shear strain amplitude and the nature of the soil (the latter represented by the plasticity index PI). The variation of modulus and damping is then related to the magnitude of the applied load through the amplitude of the shear strains induced within a succession of co-axial cylinders.…”

Soil-structure interaction in the seismic response of an isolated three span motorway overcrossing founded on piles

“…To take into account soil nonlinearity, suitable shear modulus degradation and damping ratio curves are used in the linear analysis to define the soil properties according to the maximum shear strain experienced by the soil during the earthquake. For soils A1, P1a and P1b (see Table 1) experimental curves obtained by Crespellani and Simoni [13] are adopted whereas for soil A2 (mainly gravelly sands) curves proposed by Vucetic and Dobry [14] for Ip = 0% are considered ( Figure 4). Furthermore, in order to investigate the site response sensitivity to the nonlinear behaviour of the soil, analyses with the low-strain properties are also carried out.…”