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+--- Thread: Calculation issues of Pipe-soil friction [F] in Soil Model Wizard (/thread-743.html)
Calculation issues of Pipe-soil friction [F] in Soil Model Wizard - shaswin - 10-06-2025
https://help.ple4win.nl/index.html?longitudinal_friction.htm
According to NEN 3650-1:2020 the deadweight has also a large influence in pipe-soil friction for large diameters. This is missing in the formula, see green box below. The additional deadweight value has a positive or negative influence in the pipe-soil friction.
Source: NEN 3650-1
I know you can take this manually into account by using the CFA factor in the F input table. I can't check if the Soil Model Wizard also generates for CFA = tan(delta) in the F (longitudinal friction) table. This isn't mentioned in the help file at: https://help.ple4win.nl/index.html?longitudinal_friction.htm
Another issue is given below that peat is set to zero. This can't be the case, because it has an angle of internal friction of 15 degrees and has an adhesion value. I know the value is low, but not zero. So, setting the pipe-soil friction for peat to zero is incorrect in the Soil Model Wizard. It is not mentioned in the NEN 3650-1 to set the value on zero for peat.
https://help.ple4win.nl/index.html?longitudinal_friction.htm
Also for HDD you can't set the friction on zero by default for example for low temperature pipelines like gas (RTL and HTL) and water pipelines. You have to use the bentonite friction, see C.4.5.5.3 and C.4.5.6 (NEN 3650-1:2020). So this is incorrect in the Soil Model Wizard.
Only for 'hot' or 'warm' pipelines for example above 50 degrees Celsius you can set the friction on zero, see article C.4.5.5.2 (NEN 3650-1:2020).
RE: Calculation issues of Pipe-soil friction [F] in Soil Model Wizard - Dr. J Foerster - 10-06-2025
Thank you for your input. We will look into this and make changes to the Soil Model Wizard after evaluation and if we see it as an useful update to the current functionality.