Excavation operations: Cut, Fill, Ramp and Trench
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This article covers the basic features of the excavation feature set, which makes it easy to rapidly model, simulate, and quantify the bulk and detailed excavation phase.
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How to Create an Excavation
In this tutorial you will learn how to create a detailed excavation plan.
Summary
- The excavation tool creates an editable volume, the "excavation boundary", to manipulate through operations such as cuts, fills, and ramps
- Access the excavation tool from Terrain, on the left toolbar
- The Excavation Operation is comprised of two tabs:
- Add Operations - make cuts, fills, and ramps
- Excavation Plan - view and edit operations per milestone, edit excavation boundary and settings, and view and export the excavation breakdown
Excavation Operations
Notes:
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The excavation boundary, which encompasses the area of all your excavation operations, is automatically created along with your first excavation operation and auto expands itself to fit the geometry of subsequent operations.
- You can still manually edit the sketch (only on topographic maps) to minimize the boundary’s covered area to exactly what you need and this may speed up the performance.
- The entire map is the boundary for flat maps.
Cut and Fill
- Select Terrain, then Excavation Operation
- Under Add operations, select Cut to remove material, or Fill to add material
- Click points with polyline tool to create a polygon (3 points min.)
- Click Done
Cut/Fill Settings
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Define the cut depth (or fill height) by inputting an elevation
- Simply deduct the depth or add the height from zero for a flat map E.g. -3 [m]
- Use a sea-level elevation for a topographic map E.g. 42 [m]
- Find and use the local sea-level elevation by clicking Select elevation from 3D viewer button
- The Timeline will define the first milestone where the operation will be visible in your scenario. You can also change the operation’s order within the current milestone using the Step option.
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Click Adjust to angle all the walls of the cut/fill
- Slope inwards or outwards from the sketch
- Define the slope ratio
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Ramps
- Go to Terrain, then Excavation Operation
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Under Add operations, select Positive Ramp or Negative Ramp
- Note: Ramps are only available after making a cut or fill
- Position the ramp along the wall of a cut or fill
- Click Done
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Ramp Menu
- Define width, height, and percentage grade (slope)
- Define stable soil angle (side-wall slope)
Ramp Settings
- Include as earthwork volume: Turn ON to include ramp volume in the total bulk excavation volume
- The Timeline will define the first milestone where the operation will be visible in your scenario. You can also change the operation’s order within the current milestone using the Step option.
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Click Adjust to
- Define width, height, and percent grade (slope)
- Define stable soil angle (side-wall slope)
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Trench
The Trench operation will automatically remove material by sweeping a cut-profile along a path.
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Creating a Trench Excavation Operation
- Select Terrain (1) > Excavation Operation (2) to add excavation operations
- From the Add Operations (3) panel, choose Trench (4)
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Defining Trench Geometry
đź’ˇ Note: trench geometry is defined by a profile swept along a path. The profile and the path can be customized.
Trench Path
To define the trench path you must create a polyline that is not self-intersecting; angled corners and arc’s are ok. If you are creating a new trench the sketch tool will automatically launch after adding the trench excavation operation. If you wish to edit an existing trench you will need to enter the sketch tool from the trench's settings panel using Edit Sketch (1)Â
Trench Profile
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Straight trench:
Straight trenches have only one setting: Trench Width Bottom. The trench will have a consistent width -the width at the bottom is the same as the width at the top.
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Sloped trench:
Sloped trenches have two settings: Trench Width Bottom and Wall Slope Ratio. Use the Trench Width Bottom setting to define the width at the bottom of the trench. The Wall Slope Ratio, sets the rise/run of the walls with respect to the trench depth . e.g. 1:1 result in walls sloped at 45° (from vertical), while 2:1, results in walls sloped at 30° (from vertical). 1:1 ratio is less steep than 2:1 meaning 1:1 results in a trench that is wider at the top than 2:1.
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Straight trench:
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Sloped Bottom
From the Sloped Bottom tab (1), you are able to slope the bottom of the trench along its length by changing the Grade setting (2). By default, the grade is flat (set to 0%), the more you increase the percentage, the steeper the slope.
In the example below we use a grade of 5%. The depth of the trench will increase along its path (indicated by the arrow) at a 5% slope, beginning at the starting point of the trench path (as defined in the trench path sketch).Â
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Trench Examples
See below image for a side-by-side comparison of different trenches.
Excavation Plan
- Go to Excavation, and then Excavation Plan
- See the excavation operations listed and separated by milestone
- On the operation card, click on the three dots to see options, such as:
- Edit Details - reopen the cut/fill edit menu to adjust the operation
- Duplicate - make a copy of the operation, which can be dragged to move
- Create fill from cut - to use the shape of a cut to create a fill
- Move operation
- Delete Operation
Excavation Sequencing (Boolean Operations):
The operations (cut, fill, ramp, trench) are applied in sequence to modify the volume of the original terrain or map the same way material has to be moved on/off your actual construction site.
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- Cut operations remove material from site.
- Fill operations add material back to the site.
- Ramp adds or removes material to access the bottom of the excavation.Â
- Trench's are narrow, linear cuts typically for utilities.Â
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Boolean Logic:
As seen in the image below the order of the Cut 1 and Fill 03 will impact the map appearance as well as the excavated volume.
Unlike model or resource sequencing, the excavation tool use Boolean logic to add or remove material from the map volume. This logic means that each operation is applied one after another, modifying the terrain progressively:
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Example of Removing a Positive Ramp
Since a ramp is a raised (positive) feature, you need to "dig" it out by using a cut. This effectively removes the ramp from the excavation. You could create a new cut to do this, however, it is easier to duplicate the initial excavation and adjust the sequence.Â
- To achieve this, duplicate your final bulk excavation cut (the one that the ramp was placed against).
- Move the duplicated cut below the ramp in the excavation sequence.Â
This sequential operation ensures that the ramp is removed while maintaining an accurate overall excavation volume and shape.
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Example of Backfilling an Excavation
If you need to backfill an excavation, the following steps are involved and pictured below:
Fill Operation:
- Use a fill operation to backfill the excavated area.
- Use the Fill to Terrain option to fill based on the original topography.
- Offset of 0m to ensures that the fill operation aligns with the existing terrain.
- Set the top color to Map Projection to hide the fill if desired.
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Editing Excavation Settings:
- Under Excavation Plan, Click Edit Excavation Settings
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Here you can edit the sketch of the boundary, and change the color of the boundary or excavation operations
- Existing Grade - Calculated sea level of initial excavation surface
- Boundary Surface - Select default texture or color for the area surrounding the excavation operations
- Excavation Color - Select default texture or color for the excavation operations areas
- Edit Polyline - Use polyline tool to edit excavation boundary sketch
Earthwork Takeoff:
- Under Excavation Plan, click Earthwork takeoff
- Here you can view and export a breakdown of the excavation operations performed to date
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Overview tab -
- Swell Factor - percentage adjustment representing the increase in volume
- Project total cut - calculated compact and loose volumes of cuts
- Project total fill - calculated compact and loose volumes of fills
- Milestone Breakdown - summary of milestones and volume of materials used
- Export breakdown as a .csv file
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Detailed Breakdown tab -
- Tabular breakdown of each element, occurring milestone and volume used
- Export breakdown as a .csv file
Creating a Backfill to the Original Map
Watch this video to learn how to create a backfill to the original map.
Tips & FAQ
Creating Excavation Lifts and Benching
Simulating your excavation in lifts will allow you to visualize and communicate the excavation process, ensuring efficient and safe movement of material throughout the excavation. Creating lifts in cmBuilder can be done easily using a few tips outlined below.
- Create your first cut by sketching around the building outline or excavation footprint
- Tip: Use the Project from 3D sketch tool to quickly outline the Slab on Grade or other elements from your 3D model.
- Tip: Use the Project from 3D sketch tool to quickly outline the Slab on Grade or other elements from your 3D model.
- Specify the cut depth to be your desired lift height (10ft in the example).
- Duplicate the building outline cut.
- Click and drag the duplicated cut into the subsequent milestone and edit the depth to 10ft.
- Note: If you are creating many lifts, you may wish to apply a slight offset to the sketch to avoid co-planar faces and improve performance. See:
- Note: If you are creating many lifts, you may wish to apply a slight offset to the sketch to avoid co-planar faces and improve performance. See:
- Repeat this process for other lifts.
- Tip: You can also apply an offset to the sketch, as seen below, to easily incorporate benching.
Optimizing Your Excavation
Here are the instructions on how to create an optimized excavation:
- Make sure to work with the latest excavation algorithm available for improved performance. Here are the steps to activate it:
- In the Project Page, Click on the scenario "3-dot menu"
- Select the option "Scenario Settings"
- Activate the "V3-Manifold" option
- Try to reduce the amount of operations by combining them.
- Use Projected Zones instead of Cut/Fill to Terrain to change the ground color
- Simplify the excavation boundary and cuts sketch for points that can be removed without altering the geometry too much
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