Introduction

The Depth Correction Due to Inclination feature allows you to calculate and apply the depth correction to the Depth field in the CPT_DATA table, according to the formula detailed below.

When this calculation is applied, Depth values in CPT_DATA are moved to Penetration_Length, and the corrected depth is written to Depth.

The depth of cone penetration tests can be corrected for inclination by the equation:

Where:

$//<![CDATA[ \begin{array}{l}z\end{array} //]]>$ is the penetration depth, in m. This value is written to Depth.
$//<![CDATA[ \begin{array}{l}l\end{array} //]]>$ is the penetration length, in m. This value is taken from Depth, and is copied into Penetration_Length.
$//<![CDATA[ \begin{array}{l}z\end{array} //]]>$ is a correction factor for the effect of the inclination of the cone penetrometer relative to the vertical axis

Equations for the calculation of the correction factor $//<![CDATA[ \begin{array}{l}C_h\end{array} //]]>$ for the influence of the inclination of the cone penetrometer relative to the vertical axis, on the penetration depth:

1. For a now-directional inclinometer,

   $$//<![CDATA[ \begin{array}{l}\displaystyle C_h = \cos \alpha\end{array} //]]>$$

   Where:
        $//<![CDATA[ \begin{array}{l}\alpha\end{array} //]]>$ is the measured angle between the vertical axis and the axis of the cone penetrometer, in °. This value is taken from Slope_Indicator in CPT_DATA.

2. For a bi-axial inclinometer,

   $$//<![CDATA[ \begin{array}{l}\displaystyle C_h = ( 1 + \tan^2 \alpha + \tan^2 \beta ) ^{-0.5}\end{array} //]]>$$

   Where:
        $//<![CDATA[ \begin{array}{l}\alpha\end{array} //]]>$ is the angle between the vertical axis and the axis and the projection of the cone penetrometer on the fixed vertical plane, in °. This value is taken from Slope_Indicator_1 in CPT_DATA. 
        $//<![CDATA[ \begin{array}{l}\beta\end{array} //]]>$ is the angle between the vertical axis and the axis and the projection of the cone penetrometer on a vertical plane that is perpendicular to the plane $//<![CDATA[ \begin{array}{l}\alpha\end{array} //]]>$, in °. This value is taken from Slope_Indicator_2 in CPT_DATA.

The Depth Correction function will use the bi-axial correction factor if Slope_Indicator_1 and Slope Indicator_2 have data. The now-directional correction factor will be used if Slope_Indicator has data. Bi-axial has precedence over now-directional.

If Slope_Indicator, Slope_Indicator_1 and Slope_Indicator_2 all have data, then bi-axial correction factor will be used.

Applying the Depth Correction due to Inclination Calculation

This function applies the depth correction calculation is located in INPUT | Add-Ins > Datgel CPT Tool > Depth Correction due to Inclination. It runs only from the CPT_DATA table, meaning you must have this table active before you can use the function.

Alternatively, the function INPUT | Add-Ins > Datgel CPT Tool > Depth Correction due to Inclination for multiple Strokes can be used to apply the depth correction calculation to all or selected list of CPTs. This function can be run from any table in INPUT.

You should see a window similar to the following:

You may use a combination of left click, left click-drag, ctrl + click and shift + click to select the desired CPTs, and the arrow buttons in the middle to move CPTs to the right or left grid.

Click OK to apply the depth correction calculation. The progress bar and label on the bottom right will display the current status of the calculation process. The depth correction calculation will only be applied if the Penetration_Length field is empty for all rows for a particular CPT, and the program will skip the CPT if a Penetration_Length value is found for a CPT. A list of skipped CPTs will be displayed at the end of the calculation process.