Ground Design Surface Grid

Calculate a grid and quantities between two surfaces

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TerrainGridGndDes

 

 

This function allows you to generate a model of a combination of two surfaces that can be thought of as the "ground" and "design" surfaces. General details are the same as those described for the Single Surface DTM. The difference is that the grid points will generally track along a ground surface, but will follow the second "design" surface whenever it is found. This means that the resulting grid represents an 'as built' situation.

The gridded points on the design surface are stored with a different flag compared to the ground surface, so that subsequent contours and 3D models can show the design portions in a unique colour.

When setting the "Hole Distance" for this function, it is usually necessary to set a much larger 'hole' distance when gridding the design surface. This is because the point interpolation procedure has to reach from one side of a terrace to another.

Volumes and areas of the earthworks will be calculated and displayed. These are the quantities of cut and fill between the two surfaces, as well as the plan areas of cut and fill. The amount of topsoil to be stripped can then be entered, as well as a bulking or compaction factor for the excavated material. To increase the amount of cut available due to bulking, set the factor greater than 100%. To decrease the amount of cut due to compaction, set the factor below 100%.

This last part of the function cycles so that further topsoil and compaction factors can be entered. Click Cancel to terminate.

You should read the general discussion on DTM Volumes.

Procedure

  1. The DTM Grid Volumes - Grid Type page displays.

  1. Select the Ground/design surface option and click Next.

  2. The DTM Grid Volumes - Surface Details page displays.

  1. Select the relevant surfaces and click Next to continue.

  2. The DTM Grid Volumes - Grid Details page displays.

  1. Fill in the relevant data and click Next to continue.

  2. The DTM Grid Volumes - Search Distances page displays.

  1. Fill in the relevant data and click Next to continue.

  2. The results display in the Output Bar.

  1. The Topsoil Stripping and Compaction options display so you can change the topsoil and compaction factor parameters, if required.

  1. Fill in the relevant data and click Calculate to continue; or Finish to update the totals and end the function.