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Soil friction HDD in Ple4Win v4.4.2
06-08-2017, 07:40 PM, (This post was last modified: 06-08-2017, 07:43 PM by shaswin.)
 shaswin Senior Member Posts: 367 Threads: 191 Joined: Dec 2008 Reputation: 0
Soil friction HDD in Ple4Win v4.4.2
According to the changelogs and manual a zero friction is taken into account with 8 mm longitudinal displacement:
http://www.ple4win.nl/help/longitudinal_...cement.htm
http://www.ple4win.nl/help/longitudinal_friction.htm

Change Logs:

Manual:

A zero friction is the case when there is a hot pipeline, see C.4.5.5.2 NEN 3650-1:2012. But when you normal gas pipelines or low temperature pipelines friction is allow with a HHD, see C.4.5.5.3 and C.4.5.6 NEN 3650-1:2012 in the operation phase of the pipeline. It is too conservative too allow only zero friction in HDD by default. Let the user make the choice if the user want to apply zero friction.

In D-Geo Pipeline an avarege longitudinal displacement of 7.5 mm is used, see screenshot from D-Geo Pipeline manual below:

However Ple4Win uses 8 mm for the longitudinal displacement. I think it is averaged between 6 and 10 mm for soft clay, see C.4.5.1 NEN 3650-1:2012. Why not use 7.5 mm like in the manual of D-Geo Pipeline where this is based on an average of estimated values.
07-08-2017, 04:40 PM,
 ir KW Radder Moderator Posts: 22 Threads: 2 Joined: Sep 2008 Reputation: 0
RE: Soil friction HDD in Ple4Win v4.4.2
Hi Shaswin,

We have chosen to take a HDD for a hot pipeline as the default case in the Soil Wizard. Then the friction should be set to zero according to C.4.5.5.2 of NEN 3650-1+C1:2017. According to C.4.5.5.3 of the same standard applying friction between soil and pipe is allowed for gas pipelines with large diameter and limited temperature differences. However, this is due to locally rising of the pipe in the bore hole and must be analysed case by case by the user. It is not clear at what diameter there is a question of a large diameter and PLE cannot make such a decision. So it is better that the user changes the results of the Soil Wizard if necessary, for instance by specifying, possibly locally, the friction factor CFA in input table F. This gives a better approach of the behaviour of a rising pipe in the bore hole.

Concerning the displacement at maximum friction in D-Geo Pipeline: In the Manual a value of 7.5 mm is proposed, but in the Software 8 mm is applied (source Roos + Bijl).

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