Constitutive models for 1D ground response analysis typically include modulus reduction and damping curves as input parameters (Hashash et al. 2010), which represent the desired behavior of the soil. Most of the constitutive models use modified Masing rules to define unload/reload behavior; however, these rules typically introduce a misfit of the input damping curve, resulting in a mismatch of the desired behavior (Hashash et al. 2010). The model by Yniesta et al. (2016) is able to match perfectly an input damping curve and a modulus reduction curve. This constitutive model does not include viscous effects. The effect of the rate of deformation is relatively well understood (Sheahan et al. 1996) but is not integrated in existing 1D constitutive models.

This project aims at introducing viscous effect in the previously derived model (Yniesta et al. 2016). The model will be implemented in a 1D ground response analysis software and the impact of viscous effects on site response will be assessed.

References:

Hashash Y. M. A., Phillips C., and Groholski D. R. (2010) “Recent advances in non-linear site response analysis.” Fifth International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, San Diego 2010.

Sheahan, T.C., C.C. Ladd, and J.T. Germaine (1996) “Rate-dependent undrained shear behavior of saturated clay,” J. Geotech. Engr., ASCE, 122 (2), 99-108

Yniesta, S., Brandenberg, S.J., and Shafiee A. (2016) “One-dimensional Non-linear Model for Site Response Analysis” Soil Dynamics and Earthquake Engineering, under review.