I have a site with a substantial cut fill ratio, pavement, building, etc. I am curious how you guys approach your earthwork in regards to TOPSOIL, NOTCHING OUT FOR PAVEMENT, etc. I am used to doing a surface to surface comparison but would like to get down a little closer on this site.Can this be done as a whole and not have to parcel out the topsoil and pavement sections in a separate calculation?
Any advice is appreciated.
this should be of interest to you
Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
I use the dynamic differential TIN technique as suggested by @Joe-Bouza
Unfortunately as Civil 3D is geared for extracting datum surfaces from a corridor if you don't have/need a corridor it takes a bit of upfront work to prepare but it is very useful technique.
I use it to create base of topsoil models using the sampled depths at each sample location rather than just dropping the entire surface by a constant value.
I also used the technique last week to create a landform that was dynamically linked to a reference of the initial formation model resulting in a cut/fill balance for earthworks (from a surplus of 118,000m³) which probably took less than 15 minutes to do (and wasn't simply dividing the surplus volume by the area and raising the model by a constant value which would give an odd step at the boundary...!!!!!).
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
I'd be more comfortable with method 2.....
As you have completed the tedious step of creating the boundaries with the crucial 10mm offset you are only a couple more steps away from the dynamic differential TIN method....
and you don't need multiple copies of the formation surface with many Outer/Hide/Show boundaries to model the various construction types.
I've lost count of the number of "cut and fill" drawings I've seen that say "based on existing ground to finished levels"....
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
All good advice so far so I'm not sure what I can add..
Existing;
What you do depends on what is on the existing site. If it is all grassed then raise / lower is simplest however other instances of concrete pads or roadways we use the differential method.
You also may need to take into account geology results.
Stockpiles or mounds, you may want to remove these but note the volumes before hand.
Proposed.
First model the site finished platforms & create a new surface pasting the finished one into that, lower by the approx. average construction depth across the site. Now create a volume surface between the eg Stripped and approx datum.
Based on the results raise or lower the datum until you get as close to zero as is reasonable noting the level change.
Change the proposed surface to suit by remodelling to this value, remove the original raise lower edits and check the results tally up. (reiterate until you get close to zero).
Now I usually turn to the differential modelling technique to prove the level drop and use the raise lower again until you meet a close to zero value before remodelling anything.
I find that guessing using raise lower cuts down the remodel time until the last couple of iterations before you are within 200-600 **** of material. I have never actually managed to get zero 🙂
Other things to note; you may have stockpiles of material which can be used in construction so remember these volumes and use a spreadsheet to calc them out.
Use landxml or Dref the surfaces. Keep the, existing datum model file, proposed finished, proposed datum and cut and fill files separate to reduce sizes. The other benefit to this is you can keep the previous incarnation of the design and overwrite the xml file but importantly return back at any time.
M
Mike
Is the forum using software which automatically sensors what it thinks is a rude word?
It says in my post " 200-600 ****" which should have read 200-600 c um (with no space). It was definitely right when I clicked post.
M
You just need to assign a construction thickness value to your boundary polylines (which must be +ve) and then make a thickness surface from these. You will also need polylines at 0 level to define the extremities of the site and then create a Volume Surface with this thickness surface as the base surface and the finished as comparison.
Paste the Volume surface into a new surfaces (Proposed Formation) and you have all the section/profile tools available as well which you don't with a regular volume surface.
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
LOL - nanny state gone mad....!!!!!
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
No worries - it's worthwhile getting to grips with it....very powerful technique
If your road construction thickness changes from 450mm to 600mm for example then the polyline elevation for the road areas gets changed to 0.6m and all the models update.
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
Absolutely...if you have the perimeter boundary of both types, simply create the 10mm offset and then assign 0.63 and 0.45 as the polyline elevations. You will essentially have two lines 20mm apart in plan and 0.180m in elevation. The horizontal distance avoids the vertical step in the TIN and makes little or no difference to volumes in practice.
You can also then run profiles and show level differences or even a level differences plan with the various construction thicknesses analysed.
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
That's the beauty of this method. As the areas of construction change on the site you don't necessarily need to re-do the surface model just the depths (which are 2d and can be harnessed as parcels or as hatched areas for construction plans.
Ensure you include a small gap between them so they'll transition out.
I liked it so much I wrote a tool to create the dynamic surface for me using 2 base surfaces.
M
@Anonymous wrote:
I liked it so much I wrote a tool to create the dynamic surface for me using 2 base surfaces.
M
I'd have hoped Autodesk would have come up with something for this technique.
It's way beyond my competency but I wouldn't have thought it was too onerous for Autodesk programmers as not all modelling is corridor focussed.....but wait.... it isn't Infraworks or 360 so no chance of it happening any time soon...!!!!
neilyj (No connection with Autodesk other than using the products in the real world)
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
Joe Bouza
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.
