﻿ Ultimate hor. soil reaction [RH]

# Ultimate hor. soil reaction [RH]

Calculations of Ultimate horizontal soil reaction

The soil range of importance for the Ultimate horizontal soil reaction is from ground level to the bottom of the pipeline.

NEN3650-1992

For the NEN3650-1992 calculation methodology two formula's are given, one for sandy soil types and one for clayey/peaty soil types.

Sandy:

Clayey/peaty:

 Qhor Ultimate horizontal soil reaction Kq Function of φ and H*/D 1 (for sandy soil types) σk Vertical grain pressure at pipeline axis (see General parameters) α constant: 0.6 Kc Function of φ and H*/D 2 (for clayey/peaty soil types) cu Undrained cohesion (averaged over range from ground level to the bottom of the pipeline) φ Angle of internal friction (averaged over range from ground level to the bottom of the pipeline) H* Height of soil coverage from ground level to pipeline axis D Outer diameter of pipeline

NEN3650-1:2012

The formula for sandy soil types is not changed in the NEN3650-1:2012 calculation methodology. For clay/peat soil types the NEN3650-1:2012 calculation methodology distinguishes slow and fast deformation. The formula's for clay are:

Clayey/peaty, slow deformation:

Clayey/peaty, fast deformation:

 Qhor Ultimate horizontal soil reaction Kq Function of φ and H*/D 1 σk Vertical grain pressure at pipeline axis (see General parameters) α constant: 0.6 for installation method trench and 1.0 for non-trench installation method. 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. Kcu Kc Function of φ and H*/D 2 cu Undrained cohesion (averaged over range from ground level to the bottom of the pipeline) φ Effective angle of internal friction (averaged over range from ground level to the bottom of the pipeline, using the Effective Young's modulus of soil for the same range with a depth as at bottom of pipe) H* Height of soil coverage from ground level to pipeline axis D Outer diameter of pipeline

1The function Kq is defined as:

 Where: Kq∞ αq H* Height of soil coverage from ground level to pipeline axis D Outer diameter of pipeline Nc Function of φ 3 d∞c Function of φ 4

2The function Kc is defined as:

 Where: K∞c αc Nc Function of φ 3 d∞c Function of φ 4 H* Height of soil coverage from ground level to pipeline axis D Outer diameter of pipeline

3The function Nc is defined as:

4The function dc is defined as:

Last changed: 20/10/2016