Correlations of stiffness with spt N value for the HS model

For Hs model, you need E50. This parametre is difficult to correlate in the literature. Try watching plaxis video, "parameters for clay" and "parameters for sand". 

I'm using this relationship

Dear Nitha,

For stiffness there is no reliable correlation from SPT. SPT is primarily to determine strength parameters...
Be aware that correlations may be quite accurate, or may be just an average of a wide scatter of values. Hence, reality maybe somewhere in between 0.25 and 4 times the correlation value.

With kind regards,

Dennis Waterman

Thanks for the reply, we have only SPT values for the projects that's why.