Hill Excavation Volume; 2 slopes

[CyrusLSteele]

I have a project where we are excavating fill for our project from a nearby hill, which we have to leave in a certain condition when finished.

The portion we can excavate from, is bounded by a creek at the base of the hill, and a sewage pipe ROW running through the hill. What I would like to do is have Civil3D build a surface from the 15ft contour running beside the creek at 1% grade up hill, until it intersects with a 3:1 slope coming down from the edge of the ROW.

What is the simplest way to get civil to find the intersection of the two grades.

I have extracted the contour and converted to a feature line, and I have a feature line created showing our upper boundary as well.

[dgordon · Accepted solution]

I would create a surface using the contour line and a feature line which is well past the other slope condition. then just daylight to the newly made surface with the other feature line.

[CyrusLSteele]

That's how I intitially calculated it, but my volume was showing a fill of 40 cubic m, causing a change in my net cut number. My design surface should be completely below mt existing ground, so I was concerned that that method may not have been giving me accurate numbers. Any idea why I would being seeing this extra material?

Surface was defined using extracted contour, upper boundary featureline, and my grading line as breaklines.

[dgordon]

maybe the initial slope was up instead of down or vice versa. happens all the time in grading. check the elevations of the initial surface created after applying the design slope.

[Joe-Bouza]

Are you certain the existing slope from the ROW is flatter that 3:1?

[doni49]

Can you post your dwg file?  What version are you using?

[CyrusLSteele]

I found the issue, one of the PI's on my upper feature line had a wrong elevation.

[CyrusLSteele]

I had to turn on shaded views to see where the fill was coming up through my surface.