﻿ Neutral/Real top soil load [SOILNB]

# Neutral/Real top soil load [SOILNB]

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.

 Qn Neutral top soil load γ (Mean) volume weight (averaged over range from ground level to top of pipeline) H Height of soil coverage from ground level to top of pipeline γ1 (Mean) volume weight (averaged over range from ground level to freatic plane) H1 Height of soil coverage from ground level to freatic plane γ2 Volume weight (saturated) (averaged over range from freatic plane to top of pipeline) H2 Height of soil coverage from freatic plane to top of pipeline γw Volume weight of water

Illustration of properties for neutral top-soil load

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.

NEN3650-1992

The NEN3650-1992 calculation methodology uses the following formula.

 Qk Real top soil load Qn Neutral top soil load fk Shrinkage factor 1 Qp (Maximum) Top soil reaction

1The shrinkage factor is defined as:

 Qp (Maximum) Top soil reaction Qn Neutral top soil load μ Shrinkage percentage (averaged over range from ground level to top of pipeline) D⋅kvmin Shrinkage pressure (averaged over range from ground level to top of pipeline)

NEN3650-1:2017

For the NEN3650-1:2017 calculation methodology the formula used is:

 Qk Real top soil load Qn Neutral top soil load μ Shrinkage percentage, if the installation method is trench compressed fill, the shrinkage percentage compressed is used instead (averaged over range from ground level to top of pipeline) D Outer diameter of pipeline kv,top Qp Ultimate top soil reaction zmax kv Downward vertical soil stiffness kbuis Epipe Young's modulus of pipe material Iw ky Dimensionless deflection coefficient, a value of 0.1 is used Dg Averaged diameter of pipeline t Wall thickness

Last changed: 10/30/2019