AutoCAD Civil 3D General Discussion

AutoCAD Civil 3D General Discussion

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Distinguished Contributor
bigmaz
Posts: 150
Registered: ‎09-27-2006
Message 1 of 8 (411 Views)

Civil 3D borehole importer any use?

411 Views, 7 Replies
02-21-2012 03:55 AM

Hi

 

Am I missing something with the borehole importer.  What use is it, if it just triangulates between boreholes?  Surely there should be an option to be able to set an average offset of the existing ground where there are no BH information?  Or is there?  I cannot seem to find information that sorts this.  Can anyone help?

 

Regards

Martin

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Joe-Bouza
Posts: 5,187
Registered: ‎12-15-2008
Message 2 of 8 (404 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 05:09 AM in reply to: bigmaz

Sounds to me like you could lower EG and add the borehole data to it?

Thank you

Joseph D. Bouza, P.E. (one of 'THOSE' People) Civil 3D 2012 & 2013
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Note: Its all Resistentialism, so keep calm and carry on

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Distinguished Contributor
bigmaz
Posts: 150
Registered: ‎09-27-2006
Message 3 of 8 (398 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 05:23 AM in reply to: Joe-Bouza

Hi Joe

 

Thanks for your reply :smileyhappy:

 

Although, I dont follow....  how does this solve the problem?  I could still end up with below ground triangles going through EG.  If I have a valley, and 1 borehole either side, the BH info will interpolate those 2, and will not take into account the EG triangles and go straight through it.  Have you used the borehole importer?

 

Thanks

Martin

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neilyj
Posts: 3,986
Registered: ‎08-01-2008
Message 4 of 8 (394 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 05:50 AM in reply to: bigmaz

The method to overcome this is:

 

Create a surface for the stratum of interest where the z value is the depth (+ve) in your local units e.g. m

Create a volume surface using the stratum as base surface and EG as comparison

Paste this to a new surface and you have a dynamic stratum surface for volume calcs, profiles etc

If more borehole info becomes available simply add to the stratum depth surface and rebuild.

 

This will accurately reflect valleys and ditches and hills (which may not be geologically correct) but is usually ok

neilyj
(No connection with Autodesk other than using the products in the real world)


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Distinguished Contributor
bigmaz
Posts: 150
Registered: ‎09-27-2006
Message 5 of 8 (389 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 06:10 AM in reply to: neilyj

Hi Neily

 

Are you saying, the strata is basically an offset from EG?  I need to be able to use the surface created from the BH Importer.

 

 

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neilyj
Posts: 3,986
Registered: ‎08-01-2008
Message 6 of 8 (382 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 06:34 AM in reply to: bigmaz

The input to the borehole importer requires units to be cm and -ve to allow the borehole sticks to be drawn correctly in profiles views. You'll need to manipulate the borehole importer points to be in m and +ve.

 

DO NOT USE THE REDUCED LEVEL SURFACE THAT THE IMPORTER DERIVES AS IT IS INADEQUATE AS YOU HAVE FOUND

 

If you follow the steps posted and disply tooltips you will find for example that if at a certian location EG=100m and BHdepth = 6m, BH volsurf = 96m, Stratum surface = 96m. The stratum surface will mirror the ground effectively offset by the bh depth surface so you dont get the " I could still end up with below ground triangles going through EG.  If I have a valley, and 1 borehole either side, the BH info will interpolate those 2, and will not take into account the EG triangles and go straight through it" problem





neilyj
(No connection with Autodesk other than using the products in the real world)


IDSP Premium 2015 (mainly Civil 3D 2015 UKIE & Infraworks with some limited 3ds Max Design)
Win 7 Pro x64, 500Gb SSD, 1Tb HDD
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Distinguished Contributor
bigmaz
Posts: 150
Registered: ‎09-27-2006
Message 7 of 8 (376 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 07:08 AM in reply to: neilyj

Great, thanks Neily, will give that a try.  You have to forgive and bear with me, my wee brain struggles, lol.

 

Martin

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neilyj
Posts: 3,986
Registered: ‎08-01-2008
Message 8 of 8 (372 Views)

Re: Civil 3D borehole importer any use?

02-21-2012 07:19 AM in reply to: bigmaz

Yes - its a bit confusing for me at times and I've been using this technique for a long time...!!! It is pretty obvious when you think a little about it though.

 

The main assumption is that the subsurface strata varies based on how C3D triangulates between the borehole/trial pit locations which may not be the correct assumption and depends on the density of the boreholes/trialpits.

 

A similar technique (that'll really make your brain hurt) for removing the construction thickness for volume calcs can be found here http://ericchappell.blogspot.com/2012/01/magical-way-to-calculate-volumes.html

neilyj
(No connection with Autodesk other than using the products in the real world)


IDSP Premium 2015 (mainly Civil 3D 2015 UKIE & Infraworks with some limited 3ds Max Design)
Win 7 Pro x64, 500Gb SSD, 1Tb HDD
32Gb Ram Intel Xeon CPU E5-2650 v2 @ 2.6GHz (32 CPUs), ~2.6GHz
NVIDIA Quadro K4000, Dual 27" Monitor, Dell T5610
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