3.2. Soil Data [GENSOIL]

Compose soil data model

General description:

Through this function the mechanical, supporting soil data are specified and elaborated for further processing.

Function description:

The mechanical properties of the supporting soil are specified in the input data tables as polygon shaped data lines along a coordinate axis to be selected from the available coordinate axes. See the toggle table description. The function attaches the various data to the pipe nodes and constitutes the soil data model, to be used in the elaboration of the supporting soil model of the pipeline. Mutual ratio's are evaluated. The function calculates the values of the soil parameters according to :

 

calculation value = (specified mean value) *UNCF(H/M/L)


with :

UNCF(H) = UNCF



UNCF(M) = 1.



UNCF(L) = 1./UNCF

 

If it is intended to connect a half infinite long pipeline at a boundary node, the soil parameters KLS and RVS at that node must have non-zero values in order to maintain a consistent model.

If one of the ratio's KLT/KLH, KLS/KLH, RVS/RH or RH/RVT is extreme (not between 1:20 and 20:1), then the 'discrete' soil model is applied (no ellipse, discrete values of KLT, KLS and KLH, RVS and RVT and RH only).

On-bottom pipe/soil behaviour may be modelled by specifying RVT value = 0. for the whole pipeline or part of the pipeline. This implies that, if the pipe is moving upwards, the vertical, horizontal and frictional soil reactions are zero.

In case no SLCURVE table has been specified, the default soil reaction/pipe displacement curve is bi-linear.

In case a SLCURVE table has been specified, the specified curve for the lateral soil reaction/pipe displacement curve is applicable in all lateral directions. The curves in lateral and axial direction may be different.

The optional SLACK and SLCURVE tables may be used independently. SLACK and SLCURVE specifications which include the START or END nodes are ignored for these points in case of INFIN boundary conditions. If a 'SLACK' space around part of the pipeline is specified, no soil reactions are generated as long as displacements stay within the specified 'SLACK'-space.

This implies:

1.If L-SLACK=0 and X-SLACK=0, then in case of L-DISP ≥ 0 R-LAT ≥ 0 and X-DISP ≥ 0 R-AX ≥ 0 (general case) (if R-ult>0 and F>0)
2.If L-SLACK>0 and L-DISP ≤ L-SLACK then R-LAT=0 and R-AX=0
3.If L-SLACK>0 and L-DISP>L-SLACK then R-LAT>0 (if R-ult>0). If in that case X-DISP>X-SLACK then R-AX>0 (if F>0). If in that case X-DISP ≤ X-SLACK then R-AX=0

Additional soil resistance due to friction from the lateral soil reaction may be specified in tables F and RH by means of optional friction factors.


H3203, last changed: 14/09/2016

See also:

Input data table overview

Output data table overview

Design function errors, warnings and messages