Dear all,
(HS small) is a modification of the hardening soil model that accounts for the increased stiffness of soils at small strains. At low strain levels, most soils exhibit a higher stiffness than at engineering strain levels, and this stiffness varies non-linearly with strain. There are additional two additional material parameters, i.e. G0ref and γ0.7. G0ref is the small-strain shear modulus and γ0.7 is the strain level at which the shear modulus has reduced to about 70% of the small-strain shear modulus. In the absence of laboratory and field tests, some correlations are available in the literature for sand soils using relative density (Brinkgreve et al. (2010)).
Dear Abdirahman,
The Gmax = G0ref and indeed it can be obtained by as you mentioned by geophysics tests (measuring the shear wave velocity Vs).
There are different correlations for γ0.7 published online along with some suggested values. Of course, this highly depends on the soil you are interested in and whether that has similar behaviour.
Below you can find another correlation from Benz (2007):
Thank You Stefanos Papavasileiou
Dear Stefanos Papavasileiou
with thanks to Mr. Yasin for a good question,
In this regard, with considering this equation in the manual :
So, based on what you mentioned previously, the obtained module from ρVs2 formula, is equal to Gref?
in other words, what is the difference between G0 and Gmax?
Dear Zia,
The difference is that the G0 is a stress-dependent value with a power law (m).
If there is no stress-dependency of the stiffness to be considered you can specify this m=1.
Thank u all ! you have answered all the questions i got in my mind.