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.

Formula_SOILNB

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

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.

Formula_SOILRB

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:

Formula_fk2

Qp

(Maximum) Top soil reaction

Qn

Neutral top soil load

μ

Shrinkage percentage (averaged over range from ground level to top of pipeline)

Dkvmin

Shrinkage pressure (averaged over range from ground level to top of pipeline)

NEN3650-1:2012

For the NEN3650-1:2012 calculation methodology the formula used is:

Formula_SOILRB_nog_newer

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

Formula_kvtop

Qp

Ultimate top soil reaction

zmax

See Upward vertical soil stiffness

kv

Downward vertical soil stiffness

kbuis

Formula_Kbuis_new

Epipe

Young's modulus of pipe material

Iw

Formula_Iw

ky

Dimensionless deflection coefficient, a value of 0.1 is used

Dg

Averaged diameter of pipeline

t

Wall thickness


Last changed: 14/09/2016