How to add breakline to surface and project slope from that breakline

[Anonymous]

Hello learned scholars and helpful people;

I am doing a gravel pit reclamation where they want me to contour the reclaimed site. I have a slope of 20:1 from a specific offset on the west side, and 3:1 slopes from specific offsets on the other three sides.

I have an original ground surface built from survey data, and then another surface called overburden which was modeled using the outer points of the original ground surface and elevations provided by about 8 or 9 test holes (Sketchy but it's all I have.) I want to project the outer slopes down to the overburden surface and then contour that to show them what the area will look like after reclamation. I also have data for the gravel depth (below the overburden) which would be cool to model because then I could get volumes but for now I would be ecstatic to be able to do my slopes.

From the twelve thousand videos I have watched, it seems that I need to make breaklines out of my tops of slopes (feature lines) in order to assimilate them into the model, otherwise they are at 0 elevation and I can't project slopes. (I even tried drawing a 3D polyline from each end of the model but of course that isn't accurate. I have made a breakline from my feature line on the west side, and it gets absorbed by the model and looks nice, but now I can't figure out how to project from THAT line down to the overburden surface as there is no longer a feature line to project from. 

I hope all of this makes sense. Any help, videos, anything would be very much appreciated.

Thank you

Liesl

[rl_jackson]

Sounds like you just need to create some featurelines, have them take on the EG elevation and then create a Grading from the resulting FLs to create the surface.

[ChrisRS · Accepted solution]

A picture is worth a 100 words. I'm not sure what you are asking for. A sketch (cross section) would help.

Are you filing a gravel pit?

Or, are you regrading fill that has already been placed in the pit?

Is the boundary of the survey information limited to the pit area, or does is cover a larger area?

Even with out know that information, I think that I can give you some tips:

1. You have and existing surveyed surface, lets call it EG for existing surface.
2. You will create a new surface with the desired grading slopes. Let's call the surface FG for finished grade. 
   1. Your FG work needs to be in a different site than EG, say FG-Site.  *
   2. Create  a grading group using FG-Site. The Grading group will host the FG Surface. Set automatic surface generation of FG. You can also set the Volume Reference Surface to EG. 
   3. You will create feature lines, add gradings at teh specified slopes and add a grading infill to fill in the gap in the center of teh surface.
      1. Option 1: define the pad at the top of the fill. 
         1. This should be a closed feature line. Fillets, even tiny ones, at each corners are a good idea. You will want to add elevation points, at a 2' to 5' interval and then assign elevations from EG t this feature line. 
         2. Apply "slope to elevation" gradings, @ 20:1, to 3 sides this feature line. 
         3. Apply a "slope to elevation" grading, @ 3:1, EG, to the 4th side. Remember to leave a gap between the existing gradings.
         4. Apply 2 grading transitions to fill the gaps.  **
         5. Add an infill grading to fill in the pad at the top, (Creategradinginfill)
      2. Option 2: define the catch line at the toe of the fill. 
         1. This should be a closed feature line. Fillets, even tiny ones, at each corners are a good idea. Assign EG Surface elevations to this feature line. You will can incorporate a cross slope if you wish.
         2. Apply "slope to surface" gradings, @ 20:1, targeting EG, to 3 sides this feature line. 
         3. Apply a "slope to surface" grading, @ 3:1, targeting EG, to the 4th side. Remember to leave a gap between the existing gradings.
         4. Apply 2 grading transitions to fill the gaps.  **
         5. Add an infill grading to fill in the pad at the top, (Creategradinginfill)
   4. Using the Volumes Dashboard you can balance the cut fill.

*     As a best practice, I would create FG in a new drawing. DREF EG into the FG drawing.

* *  Transitions are tricky.  You may need to manually add feature lines connecting the daylight lines to close the gap, then add an infill grading.

[Joe-Bouza]

Overburden?  As learned and helpful as I may be I have no idea what this is and why it isn't part of original ground.

How would you do it on paper? That's how you do it. set your control points and control lines and target the surface you want to hit.

Assuming Overburden is og at the top of the pit and we do not know where 20:1 and 3:1 will intersect. I might take this approach.

Establish the offset lines from top of Overburden>> extract the elevations to the feature lines

west side: project grading to OG (let grading make surface <west>

make a blank surface <A> and paste OG and <West> together

North side  same but target <A>

make surface B paste OG,A and North

follow pattern for reaming sides

Surface D should be you finished reclaimed site

Personally I like grading outward, so I might be inclined to take an educated guess at the bottom elevation make a closed feature line and grade up to OG / Overburden

[Anonymous]

Thank you very much for this information. I will follow your steps and let you know how it went. 

For context, I am including the plan view and a couple of the sections. They are removing gravel and filling this area with reclaimed overburden using the 20:1 and 3:1 slopes to the top of the previous gravel/sand layer.

I appreciate your detailed instructions. 

Cheers,

Liesl

[Anonymous]

Hi and thank you for your reply.

Here are three images to show what we are trying to accomplish. The original ground surface was modelled from survey data, but the sections (A, B and C) were drawn manually based on specifications. 

Now, they want me to recontour the "reclaimed" surface (sand & gravel layer removed and filled with reclaimed overburden.) Had I known this from the start, I would have attempted this as part of my section drawings but these screen shots will hopefully clarify.

[Joe-Bouza]

Thanks. Overburden = EG from what I can tell.

[Apex-Solutions · Accepted solution]

Hello @Anonymous 

This is possible to do but it requires some setup before we can create those surfaces, what we need to do is the following:

• Create a feature line that defines the gravel pit
  • Make sure to assign the surface elevations to the feature line.
  • intermediate grade points will improve on overall accuracy. 
• Create the gradings on their own sites as mentioned by @ChrisRS , the gradings will be for:
  • Bulk Cut Grading
  • Reclamation Site.
• Create base surfaces with an outer boundary set to the previous gradings.
  • Bulk Cut Base
  • Reclamation Base.
• Combine the surfaces as mentioned by @Joe-Bouza 

I will try and explain the above with images here:

• Grade the feature line (Infill included) that defines the gravel pit extents.
  • Note that when grading internally with flat grades/slopes to curved sections you might get some issues, rather have sharp corners for these scenarios.
  • Remember to have a surface (name: Bulk Cut) automatically created for the grading objects.
  • This grading was targeted to the Bedrock surface.
  • The grading was set to 0.1:1 to achieve a near vertical cut.

• Create a blank surface and rename to Base Surface.
  • Paste the Bedrock surface into its definition.
  • Define the target line of the graded surface as the outer boundary.

• Create a blank surface and rename it Bulk Cut Final.
  • Paste the Grading surface (Bulk Cut) into its definition.
  • Paste the Base Surface into its definition.

Repeat these steps from a new feature line (exact copy of the gravel pit extents) to define the reclaimed surface with its own grading and reference surface (Sand and Gravel), here are the results:

Here is a cut through the whole site.

The volume difference between the Bulk Cut Final surface and the Reclaimed surface will be the total Overburden Volume.  

I hope this makes sense.

[ChrisRS]

As I see it, you will be working with 5 surfaces.

1. EG or OR, the existing surface
2. BED, the bedrock surface.
3. SandG, the top of sand gravel surface
4. EXCAV, the excavation surface.
5. GRADING, the grading Surface. (I choose the general term grading, rather than fill, because there may be cases where both cut and fill are involved.)

Surface Creation

Each surface needs its own site or drawing. Grading groups and automatic surface creation are helpful.

1. EG is based on your survey
2. Create BED using points manually created from your boring logs. The resulting surface needs to fully cover your pit area. If not, extend the surface using points or a feature line, estimating the elevations based on nearby boring logs.
3. Create SandG using points manually created from your boring logs. The resulting surface needs to fully cover your pit area. If not, extend the surface using points or a feature line, estimating the elevations based on nearby boring logs. (You will use SandG for volume calculations. 
4. EXCAV
   1. Draw a feature line (FL) defining the top of the pit. Assign FL elevations from EG
   2. Create a feature line (FL2) at the toe of the pit excavation.
      1. Option 1, stepped offset
         1. Create a stepped offset from FL. Step distance is your choice. How steep do you think this excavation can be? My guess: 2' step. Elevation difference does not matter, use 0'.
         2. Assign FL2 elevations from BED. (This is why step elevation difference does not matter.) 
      2. Option 2, use Grade to Surface grading object.
         1. Create a grade to surface grading object: Target Surface = BED; Select Feature line FL; Your choice of slope, maybe Slope = 0.5:1
   3. We need the bottom of the pit to match BED.
      1. Create a working surface: EXCAV-FLOOR
      2. In the definition of EXCAVE-FLOOR chose edit and paste surface BED. This creates a dynamic copy of BED.
      3. In the definition of EXCAVE-FLOOR chose boundary and add FL@ as an outer boundary. This trims the surface.
      4. In the definition of EXCAVE chose edit and paste surface EXCAV-FLOOR. This fills in the bottom of the pit.
5. GRADING.  Use whatever methods you prefer to create the grading surface. 
   1. The GRADING surface should be fully within FL.
   2. The GRADING surface does not need to follow the SandG surface.
   3. You may want to design GRADING to use up the stockpiled excavated overburden.
6. FG Finished grade - OPTIONAL.
   This will be EG for an post reclamation work.
   You may want this for rendering the complete project. 
   1. Create TIN surface FG
   2. In FG definition, Edit Paste Surface: EG.
   3. In FG definition, Edit Paste Surface: GRADING. 
7.  Volumes:
   1. Total Excavation: Tin Volume Surface, Base: EG; Comparison: EXCAV; this should be all cut
   2. Sand and Gravel: Tin Volume Surface, Base: EXCAV; Comparison: SandG; this should be all fill
   3. Reclaim Grading: Tin Volume Surface, Base: EXCAV; Comparison: GRADING; this should be all fill
   4. Overburden: Manual Calculation, Total excavation CUT -  Sand and Gravel FILL. (Be careful of signs.)
   5. Net Excavation (Borrow/Haul): Manual calculation, Total Excavation - Sand and Gravel - Reclaim Grading
      You will probably want to account for shrink fill. It you want to balance this, you would do so by modifying the GRADING surface.

@Apex-Solutions posted a great reply while I was composing this.

Good Luck,

Chris

[Joe-Bouza]

DDTS method to create strata based on bore holes might be helpful

[Joe-Bouza]

Obviously, I way under thought this little exercise Excavation surface? where is that described in the OP?

Well done  @ChrisRS  & @Apex-Solutions 

[ChrisRS]

I am a fan of DDTS. I do not think is is helpful in this situation.

Since there are multiple bore holes a single depth, or average of depths would have to be used. From the profile provided by OP, the lower strata do not look to be parallel with the EG. By definition the DDTS surfaces will parallel the  surface that they are built from.

I admit that the Sand and Gravel volume calculated using average depth DDTS will be close to the volume based on boring log point based surfaces, and may well be within acceptable earthwork accuracy limits. In this situation, using the boring log information does not seem to require excessive effort, but does eliminate questions.

The Geotechnical module may be helpful, but I am not at all familiar with it.

[Joe-Bouza]

😂

I guess I let the title confuse me

[ChrisRS]

OP does not mention the EXCAV surface. This is just the method that I would use.

This could be done with out EXCAV.

Create BED and SandG surfaces.

Create FL and FL2

Apply FL2 as an outer boundary to BED

Sand and Gravel volume: TIN Volume surface, Base: BED, Comparison: SandG  
           Assumes vertical sides. Volume of excavation batter is ignored. Any earthwork outside of FL2 is ignored.

Create GRADING surface.

Total Excavation Volume:  TIN Volume surface, Base: BED, Comparison: EG 

           Assumes vertical sides. Volume of excavation batter is ignored. Any earthwork outside of FL2 is ignored.

Net void Volume: TIN Volume surface, Base: EG, Comparison: GRADING     (This is all Cut) 

Grading Volume: Manual Calculation = Total Excavation Volume - Sand and Gravel volume - Net Void Volume

     Be careful of volume signs. Volume uncertainty from Total Excavation Volume and Sand and Gravel Volume carry through to the Grading volume.

If the excavation sides are nearly vertical the batter volume approaches 0. The larger the excavation the less relative error introduced by ignoring the excavation batter. These considerations may not be significant.

In this situation, I find the extra effort of an EXCAV surface worthwhile. The process seem more straight forward to me. The minimal extra effort to create EXCAV seem worth it to me. It yields better accuracy, eliminates accuracy questions, and requires less mental gymnastics.                                         

[Joe-Bouza]

Over my head. I see the OP added the strata to the picture but I am not seeing the purpose of the excavation surface? 

well I was even more confused when it was described as a reclaimed pit but the EG section did not have a hole. At that point I realized I had no idea what was going on😂

why cant we just grade down to overburden?

[ChrisRS]

OK, I see it now.

My method would have created BED by adding points that were at the bedrock elevation.

The DDTS would have created points at depth, and used these points to create DepthToBED surface.

Paste EG surface into BED surface, then paste DepthToBED surface into BED surface. Should get the same surface within the area defined by the bore holes.

Can you post a link to the article you referenced. I have not looked at DDTS in this way before.

[Anonymous]

Hi Joseph,

They are removing the gravel and then filling that with reclaimed overburden. The filling material will go down to the previous elevation of the gravel, with the 20:1 and 3:1 slopes within the approved area. 

[ChrisRS]

I was confused as well. The profiles posted by OP clarified it for me as well.

You said "... but I am not seeing the purpose of the excavation surface?"

As I said in post 14, this is the method I would use. EXCAV is an interim working surface that accounts for the excavation batter. It helps me visualize the process and gives more accurate volumes. (Possibly the difference does not justify teh effort.)

You said "why cant we just grade down to overburden?"

As I laid out in post 14, you can just grade down to the GRADING surface. Even after this discussion, I would not do it that way.

I always enjoy these discussions, @Joe-Bouza. 

I think we just see some things differently, and I am not able communicate what I am thinking.

Perhaps someone else can explain it to each of us! 

[Joe-Bouza]

Thanks Chris @ChrisRS 

I'm glad you read it as spirited.  all in the quest of knowledge

Cheers

[Anonymous]

Thank you for the information. 

All I really want to do at this point is to create new contours of the reclaimed overburden. 

I created a new surface using the elevation points of the original ground for the outer edge, and the sand/gravel elevation points for the inside from the test hole data. This is what the surface looks like:

Now I want to slope the west side down to the surface at 20:1, and slopes from the north, south, and east at 3:1 using the red lines below:  (these are the permit boundaries)

As you can undoubtedly tell, surface modelling is completely new to me so even making a feature line was a big deal. Most of our work uses Map, not Civil so I apologize for my ignorance. 

I have now created a feature line of the west red line from above using the surface I created of the "overburden" layer, which is the top of the sand/gravel layer: (This surface is called overburden)

I have associated the elevations of this feature line with this "overburden" surface.  My next step is to project this west feature line at a 20:1 slope to the "overburden" layer. I would repeat the same step with the other three lines, except they are at 3:1 slopes. From what I understand, I should use infill for the corners. @Apex-Solutions mentions creating automatic surface for grading objects, which I think I know how to do - it is the difference in slopes (20:1 on one side and 3:1 on the others) that is giving me trouble. 

Is this correct so far for what I am trying to achieve? I have tried to follow all the excellent instructions closely and honestly getting lost as the authors assume that I know some of the processes already. 

Thanks again,
Liesl