Upward vertical soil stiffness [KLT]

Calculations of Upward vertical soil stiffness

hmtoggle_arrow1NEN 3650-1:2020

The Upward vertical soil stiffness is only calculated for the NEN 3650-1:2020 calculation methodology. The soil range of importance for the Upward vertical soil stiffness is from ground level to the top of the pipeline. There are two formulae for trench installation: one  for sandy soil types and one for clayey/peaty soil types and there is one formula for non-trench installation. A trench installation is either 1)Trench uncompressed fill or 2)Trench compressed fill and a non-trench installation is either 3)Boring or 4)HDD.

Sandy:

Clayey/peaty:

Non-trench:

kv,top

Upward vertical soil stiffness

Qp

Ultimate top soil reaction

E

Effective Young's modulus calculated for range from ground level to the top of the pipeline, using depth at top of pipe (given in N/mm2, factor 0.2 and 0.25 are not dimensionless)

D

Outer diameter of pipeline

H

Height of soil coverage on top of pipeline

m

l

λ

ν

φt

Angle of internal friction (averaged over range from ground level to the top of the pipeline)

Epipe

Young's modulus of pipe material

Ib

Di

Inner diameter of pipeline

Info The formula for kv,top has been adapted for the calculation model used in PLE, also see the comment on page 144, NEN 3650-1:2020, C.4.3.2.

Upward_vertical_soil_stiffness (last modified: Nov 27, 2025)