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Volume calculation cut and fill between surfaces. TBC x 12D

  • 1.  Volume calculation cut and fill between surfaces. TBC x 12D

    Posted 08-02-2022 02:25
    Hi,
    Does anybody has done volume calculation between 2 surfaces on TBC and also into 12D? I would like to know if the volumes of cut and fill match properly. I have noted some difference between both softwares. Thanks

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    Wellerson Souza
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  • 2.  RE: Volume calculation cut and fill between surfaces. TBC x 12D

    Posted 08-03-2022 16:29
    Hi, 

    We do this extensively. You'll note a difference between the software packages relative to how they combine data, and or how data is collected or created.

    12d uses a "cut in" place option. The extent of the survey is exactly what you get. i.e. if you are cutting or filling layers onto a site, you get that surveyed surface only. This, as you know is overlaid onto the other surface (Super Surface). This can give a value different to what is on site.  If the survey hasn't included the batter up / down, you don't get that in your surfacing. Makes it easy to call up the surveyor/engineer and ask for the full survey.

    TBC "merges" surface data. This takes the nearest point (from the new survey/surface) and connects to the next nearest point (in the old survey / surface).  Again, if the later survey hasn't included batters(for example) you run the risk of extended triangulation. Again, This can give a value different to what may be expected.

    Solutions:
    1. Surveyors need to account for what has changed, which includes batter / interfaces.
    2. Designs need to allow for what they are interfacing to. i .e. if you are adding a new design onto an old design (i.e. a carpark has a new revision and changed the design in 50% of the carpark). Design the new carpark so that the interface location matches the same level locations on the old data.
    Or, create the new data / new surface. Add a boundary, add an additional boundary (offset say 50mm (or whatever suits the standard required), drape that 2nd boundary onto the original surface, retriangulate (add data) for the new ttm to include the draped surface, and you should have a clean interface.

    There's definite advantages in being able to utilise both packages.  This is especially relevant in a scenario whereby you are (for example) topsoil stripping a site. The surface merging means you have to be very careful about how you progress a sites earthworks surfaces. Obviously becomes really relevant on WorksOS for example.

    Regards,
    Julius


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    Julius Newman
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    Original Message


  • 3.  RE: Volume calculation cut and fill between surfaces. TBC x 12D

    Posted 08-03-2022 17:05
    My above comment was for merging / super surface comparisons, which (looking at the stockpile / depression post) may not have been the intent of the above query.

    So, checking 2 x surfaces in TBC v 5.70
    Surface to Surface = 8274m3 Fill
    Volume Grid 8273m3 at 1m
    Volume Grid 7726m3 at 10m
    Stockpile Depression (and I'm guessing this is the issue on the other post) = No value
    at depth = no value
    at increment = numerous values (doesn't correlate). Guessing that's the glitch?

    Within 12d you'll get differences, depending on the method of volume calculation. The way the packages connect triangles may also vary.
    Exact method, End Area average or prismoidal, Via Depth range review, will all give different answers (within 12d alone).

    12d 2 x Surfaces
    Exact Volume = 8273m3
    End Area (2m sections) = 8269m3
    etc, etc depending on what method you use.


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    Julius Newman
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    Original Message