Coefficient of Lateral Earth Pressure

Coefficient of Lateral Earth Pressure 1

Coefficient of Lateral Earth Pressure 1 ( $\begin{array}{l}K_0\end{array}$ ) for uncemented sands and well behaved clays in Coefficient_Lateral_Earth_Pressure_1 is defined as:

$\begin{array}{l}K_0=(1-sin\Phi') \cdot OCR^{sin \Phi'}\\ \ \\ Maximum \quad K_0=K_P=\frac{1+sin\Phi'}{1-sin\Phi'}\end{array}$

Mayne (2007), NCHRP Synthesis 368 p 42

Where:
$\begin{array}{l}OCR\end{array}$ is taken from the Overconsolidation_Ratio_1 field for fine material and the Overconsolidation_Ratio_5 for coarse material, on the CPT_DATA table.
$\begin{array}{l}\Phi'\end{array}$ is taken from the Friction_Angle_3 and Friction_Angle_1 field on the CPT_DATA table.

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Coefficient of Lateral Earth Pressure 2

Coefficient of Lateral Earth Pressure 2 ( $\begin{array}{l}K_0\end{array}$ ) for sand in Coefficient_Lateral_Earth_Pressure_2 is defined as:

$\begin{array}{l}\displaystyle K_0=C_1 \cdot \left( \frac {q_t} {\sigma_{atm}} \right)^{C_2} \cdot \left( \frac {\sigma_{atm}} {\sigma'_{v0}} \right)^{C_3} \cdot OCR^{C_4}\end{array}$

Mayne (2007), NCHRP Synthesis 368 p 43

Where:
OCR is taken from the Overconsolidation_Ratio_5 field on the CPT_DATA table.
$\begin{array}{l}C_1\end{array}$ is 0.192 in the published formula, and is stored in the Coefficient_Lateral_Earth_Pressure_2_C1 field.
$\begin{array}{l}C_2\end{array}$ is 0.22 in the published formula, and is stored in the Coefficient_Lateral_Earth_Pressure_2_C2 field.
$\begin{array}{l}C_3\end{array}$ is 0.31 in the published formula, and is stored in the Coefficient_Lateral_Earth_Pressure_2_C3 field.
$\begin{array}{l}C_4\end{array}$ is 0.27 in the published formula, and is stored in the Coefficient_Lateral_Earth_Pressure_2_C3 field.

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

Coefficient of Lateral Earth Pressure 3

Coefficient of Lateral Earth Pressure 3 ( $\begin{array}{l}K_0\end{array}$ ) for fine grained soils in Coefficient_Lateral_Earth_Pressure_3 is defined as:

$\begin{array}{l}\displaystyle K_0=C_1 \cdot \left( \frac{q_t-\sigma_{v0}}{\sigma'_{v0}} \right)\end{array}$

Kulhawy and Mayne (1990), CPT Guide p 32

Where:
$\begin{array}{l}C_1\end{array}$ is 0.1 in the published formula, and is stored in the Coefficient_Lateral_Earth_Pressure_3_C1 field.

The constants are stored on CPT_POINT_CORRELATION_PARAMETERS and CPT_PROJECT_CORRELATION_PARAMETERS tables.

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