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 |
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 |
1The shrinkage factor is defined as:
Qp |
|
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 |
|
zmax |
|
kv |
|
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