Calculation of Neutral top soil load
The soil range of importance for the Neutral top soil load is from ground level to the top of the pipeline.
Illustration of properties for neutral topsoil load 
For large diameters an expanded calculation is performed using: As this formula becomes Qn,large = Qn for Do → 0, the above formula is used for all values of Do. 
Calculation of Real top soil load
The Neutral top soil load table can either be filled with neutral or real top soil load values, depending on the chosen option for the Neutral top soil load in the Advanced Calculation Options. The soil range of importance for the Real top soil load is the same as for the Neutral top soil load, which is from ground level to the top of the pipeline.
The NEN36501992 calculation methodology uses the following formula.
1The shrinkage factor is defined as:

For the NEN36501:2020 calculation methodology the formula used is:

Last changed: 7/1/2021