Young's Modulus 1
Small Strain Young's Modulus 1 (E_0) in Youngs_Modulus_1 is defined as:
|E_0=2 \cdot(1+v) \cdot G_0|
Elastic theory, CPT in Geotechnical Practice p 74 and 94, NCHRP Synthesis 368 p 32
v = 0.2 is applied and can be varied in the Formula Tool. Published literature states: v'=0.2 applies for drained soils and v_u=0.5 applies for undrained soils .
G_0 is taken from Small_Strain_Shear_Modulus_2.
This correlation of E_0 is applicable to all soil types.
Young's Modulus 2
Young's Modulus 2 (E_0) in Youngs_Modulus_2 is defined as:
|E_0= \alpha q_c|
CPT in Geotechnical Practice p 160, Figure 6.13
\alpha is calculated from degree of loading, q_c, effective stress and reduction factor as given in the following plot.