Relative Density and Relative Density Term

Relative Density 1

Relative density (D_r) in Relative_Density_1 is defined as:

Dr= \frac{1}{C_2}\cdot ln\left(\frac{q_c \cdot W_{ehr}}{C_0 \cdot(\sigma'_{v0})^{C_1}}\right)\cdot100

Baldi et al. (1986) and Al-Homoud and Wehr (2006), CPT in Geotechnical Practice p 83

Where:
     q_c and \sigma'_{v0} are in kPa
     C_0 is stored in the Relative_Density_1_C0 field. Published value for normally consolidated 157, over consolidated 181
     C_1 is stored in the Relative_Density_1_C1 field. Published value is 0.55
     C_2 is stored in the Relative_Density_1_C2 field. Published value for normally consolidated 2.41, over consolidated 2.46
     W_{ehr} is the Wehr Correction for Calcareous Soils, this constant is defined in the Relative_Density_1_Wehr_Correction field and was suggested in Al-Homoud and Wehr (2006). If the field is empty the default is 1.The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Relative Density Term 1

Relative density term in Relative_Density_Term_1 is defined based on Relative_Density_1 on the CPT_DATA table and the values in the DG_LOG_CONSISTENCY_DENSITY library table.

Relative Density 2

Relative density (D_r) in Relative_Density_2 is defined as:

D_r= 100 \cdot \left[C_1 \cdot ln(\frac{q_t / \sigma_{atm}}{\sqrt{\sigma'_{vo}/\sigma_{atm}} })+C_2\right]


Jamiolkowski et al. (2003), NCHRP Synthesis 368 pp 41-42

Where:
     C_1 is stored in the Relative_Density_2_C1 field. Published value is 0.268 for all sands
     C_2is stored in the Relative_Density_2_C2 field. For average compressibility: C_2=-0.675, for high compressibility and sands of carbonate or calcareous composition: C_2 \leq 1.0, for low compressibility: C_2 \geq 2.0.

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Relative Density Term 2

Relative density term in Relative_Density_Term_2 is defined based on Relative_Density_2 on the CPT_DATA table and the values in the DG_LOG_CONSISTENCY_DENSITY library table.

Relative Density 3

Relative density (D_r) in Relative_Density_3 is defined as:

D_r = \left[\frac{q_{c1}}{305\cdot C_1\cdot OCR^{0.18}\cdot(12+0.5\cdot log(t/100))}\right]^{0.5} \cdot 100\\

Kulhawy and Mayne (1990), CPT in Geotechnical Practice p 84

Where:
     q_{c1}=\frac{q_c}{\sqrt{\sigma'_{v0}\cdot \sigma_{atm}}}
     C_1 is stored in the Relative_Density_3_C1 field. Published values range from 0.91 for low compressibility, 1.0 for medium compressible sands, to 1.09 for highly compressible
     t is time in years and stored in the Relative_Density_3_t field.

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Relative Density Term 3

Relative density term in Relative_Density_Term_3 is defined based on Relative_Density_3 on the CPT_DATA table and the values in the DG_LOG_CONSISTENCY_DENSITY library table.

Relative Density 4

Relative density (D_r) in Relative_Density_4 is defined as:

D_r = \frac{1}{0.0296} \cdot ln\Bigg(\frac{q_c}{2.494 \cdot (((1 + 2 \cdot K_0) / 3 \cdot \sigma'_{vo})/100) ^ {0.46}}\Bigg) \cdot \Bigg(\frac{-1.87 + 2.32 \cdot ln\Big(\frac{1000 \cdot q_c}{(100 \cdot \sigma'_{vo})^{0.5}}\Big)}{100} + 1\Bigg)


Jamiolkowski et al. (2003)

Where:
     K_0 is stored in the Relative_Density_4_K0 field. A typical value is 0.5 to 2.0

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Relative Density Term 4

Relative density term in Relative_Density_Term_2 is defined based on Relative_Density_2 on the CPT_DATA table and the values in the DG_LOG_CONSISTENCY_DENSITY library table.