Relative Density and Relative Density Term

Relative Density 1

Relative density ( $\begin{array}{l}D_r\end{array}$ ) in Relative_Density_1 is defined as:

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

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

Where:
$\begin{array}{l}q_c\end{array}$ and $\begin{array}{l}\sigma'_{v0}\end{array}$ are in kPa
$\begin{array}{l}C_0\end{array}$ is stored in the Relative_Density_1_C0 field. Published value for normally consolidated 157, over consolidated 181
$\begin{array}{l}C_1\end{array}$ is stored in the Relative_Density_1_C1 field. Published value is 0.55
$\begin{array}{l}C_2\end{array}$ is stored in the Relative_Density_1_C2 field. Published value for normally consolidated 2.41, over consolidated 2.46
$\begin{array}{l}W_{ehr}\end{array}$ 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 ( $\begin{array}{l}D_r\end{array}$ ) in Relative_Density_2 is defined as:

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

Jamiolkowski et al. (2001), NCHRP Synthesis 368 pp 41-42

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

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 ( $\begin{array}{l}D_r\end{array}$ ) in Relative_Density_3 is defined as:

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

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

Where:
$\begin{array}{l}q_{c1}=\frac{q_c}{\sqrt{\sigma'_{v0}\cdot \sigma_{atm}}}\end{array}$
$\begin{array}{l}C_1\end{array}$ 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
$\begin{array}{l}t\end{array}$ 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.

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