Both G and K should be predicted according to E and v (Poisson's ratio).
G:The range of shear modulus values encountered in natural soils is quite large.
Very soft soils may have shear modulii as small as 10MPa. At the other extreme,
soft rock modulii may be of the order of 2000 MPa;
K:The range is also large. For saturated soil with no dissipation, it is infinitely large.