Vertical modulus of subgrade reaction (k)

[nagatalluri]

Guys:

Is there a way to estimate modulus of subgrade reaction from shear wave velocity (Vs)(obtained from MASW tests) and averaged SPT blow count.

Please advice

Thanks
NT

 

[Mccoy]

Of course there is, you calculate Go (shear modulus at small strain) from Vs , apply a degradation scheme and finally apply the relevant formulas.
Or you move ahead, from Go you calculate Eo and apply a degradation scheme and finally apply the usual formulas.
If you do not degrade the modulus will be often way too high, unless the mobilized shear strenght is pretty low (small strain).

From SPT: you apply one of the relevant correlations to get E secant (which needs not to be degraded) then straight to the usual formulas.
Sorry I condensed all in 4 lines but you could write almost a book there.

One usual formula used by many is Vesic 1961, subscript s stands for soil, subscript f stands for foundation:

 

[nagatalluri]

Dear Mccoy

Thanks a lot for the response.

NT