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Backfilling Against Walls

This section explains how to calculate the mass for backfilling against walls. When you have excavations for buildings, it is common to calculate the required backfill material. To perform this calculation, you must construct an application layer (stratum) for the future terrain, for example, nnn: Future terrain. This data is often provided as a site plan in DXF/DWG format.

Figure: A = Future terrain, B = Side surfaces, C = Boundary contour, D = Width, E = Main surfaces

Backfilling can be solved in several ways. The most common method is to create a layer where you enter the building outline as a boundary contour. For this, you can use the predefined layer 80: Foundation wall. The height of the building outline, the boundary contour, should be set equal to or lower than the surface of the excavation.

Definition of Mass Type

You can define the mass type as follows:

To layers:

  • Phys.nnn: Future terrain
  • Theo.80: Foundation wall (contains the building outline)

For the "to" layers, make sure Lowest is checked.

From layers:

  • Theo.0: Surface

Since the surface layer and the layer with the building outline are at the same height, no mass will be calculated where the building is located.

Alternative Method

Figure: A = Future terrain, B = Side surfaces, C = Boundary contour, D = Width, E = Main surfaces

In this case, you digitize the boundary contour along the building walls. Then, add an extra parameter for the side surfaces, for example, 0110 Wall width. This ensures the width is included in the triangle net for the side surfaces.

You can define the mass type as follows:

To layers:

  • Phys.100: Future terrain

From layers:

  • Theo.0: Surface ((1:10000))

The surface consists of one triangle net for the main surfaces and one for the side surfaces. The "from" layer for this mass type is limited to the side surfaces. To exclude the main surface, define this under the advanced settings for the layer.