Calculations of Pipe-soil friction

The soil range of importance for the pipe-soil friction is from 200 mm above to 200 mm below the pipeline.

hmtoggle_arrow1NEN 3650-1992

The following equation is used to calculate the pipe-soil friction:

W

Pipe-soil friction

φ

Angle of internal friction (averaged over range from 200 mm above pipeline to 200 mm below pipeline)

σk

Vertical grain pressure at pipeline axis (see General parameters)

δ

Angle of pipe-soil friction (averaged over range from 200 mm above pipeline to 200 mm below pipeline)

a

Adhesion (1)

 

(1) The adhesion is defined as:

Sandy:

Clayey/peaty:

c'

Drained cohesion (averaged over range from 200 mm above pipeline to 200 below pipeline)
hmtoggle_arrow1NEN 3650-1:2020

For the NEN 3650-1:2020 calculation methodology the Adhesion is multiplied by 0.6.

The φ is calculated as the Effective angle of internal friction (averaged over range from 200 mm above pipeline to 200 mm below pipeline, using the Effective Young's modulus of soil over the same range for a depth of the pipeline axis).

In case of an HDD (Horizontal Directional Drilled) pipeline part, the pipe-soil friction is set to zero (and the displacement at maximum soil friction is set to 8 mm).

In case of peat, the pipe-soil friction is set to zero.

Longitudinal_friction (last modified: Jan 19, 2025)