Geotechnical costs

The cost of geotechnical data takes into account the structure and properties of geological materials and the geological types located across the study area. Entering the costs of geological materials and their relationship to the study area is a two-step process using the Material and Geology tabs in the Cost Parameters dialog.

Material costs

The Material tab allows the user to define the different geological material types that are to be encountered within the study area. The user can define as many different material types as required. At least, one material type must be created. To enter or edit the costs associated with geological materials, select the Material tab:

To edit an existing entry, click the cell that you want to change. To add or remove an entry, right-click the table row and then make your selection.

• Material Class (strip/ordinary) - Strip material has to be removed totally for both cut and fill. It cannot be used as fill material; the strip must be dumped from the study area. Ordinary material can be left in place under fill and if excavated, some or all can be used as fill.

• Slope - The side slope as a percentage required for the particular material when the alignment is in cut.

• Usable - The fraction of the material that is usable as fill. Some materials are actually a mixture of other materials some of which are usable for fill and others which are unsuitable. The percentage of unusable material is hauled away and discarded at the closest dump site.

• Compaction - The compaction factor is the relative volume of the material when compacted for fill compared with the original.

Note: There is no default setting option for material, but at least one material type must be generated.

Geology

The Geology type defines the actual layers of material (type and thickness) within the study area and the vertical separation and width of benches when cutting into the specified geology.

Enter/edit the geology type

1. Select the Geology tab.

2. The list on the left shows the geological types and the benching requirements associated with geological formations. Benches are stepped upward from the finished surface of the road or rail alignment to the natural surface.

3. The table on the right of the Geology tab, shows the strata for the selected geological type. By adding various material types to this table it is possible to create a detailed picture of the nature of the geology within the study area.

Add a new geology type

1. Right-click the table on the left and select new.

2. Enter a name for the geology type.

3. In the table on the right, click the first row of the Material column.

A list with the materials previously defined in the Material tab appears.

4. Select the material closest to the natural surface first.

5. Enter the thickness of the material.

6. To add a new layer to the geology type, right-click in the table and select New.

Note: The software always shows the thickness of the deepest stratum as 9999.0 when in metric or 32805.12 when in imperial units.

To remove a geology type, right-click the table on the left and select Remove.

The global default geology type, indicated by a blue check mark, is used where a geological type is required but none is specified. At least one Geology type must be defined. By defining more than one geology type within the study area it is possible to create local geological zones, where the materials encountered differ from the general geology within the study area. For example, a mountainous region may be completely compiled of various rock types. Geometry can be localized by creating a local default zone, see Local defaults zone. To change the default geology type, right-click the geology type and select Default.

When estimating earthworks, Quantm Desktop software models cross sections at 20m (or 50ft in imperial units) intervals and calculates the areas of fill and cut through different materials.

Each cross-section consists of a list of multi-dimensional points that mark changes in direction of the finished surface or changes in strata. The cross-section needs to indicate the limits of the various strata that must be excavated to form the finished surface or to provide solid foundations for the roadway and/or fill.

Other costs

The costs in this group enable you to take into account the area costs, linear costs, and fixed costs for a project. To enter these costs, select the appropriate tab in the Cost Parameters dialog.

Area costs

Area costs reflect the cost of acquiring or clearing a particular class of land.

To enter or edit an Area cost type, select the Area tab:

You can apply area costs to the entire area covered by the earthwork footprint and/or structure, or to a smaller area that is restricted to the alignment batter when the alignment is in cut or fill.

Specify a margin (which acts as an additional buffer at the defined distance), for example, to enable equipment to operate beyond the edges of earthworks or to ensure that trees are cleared to a safe distance from a facility.

To apply the area cost types create a Global Area Cost Zone or a Local Area Cost Zone and select the area cost type.

Linear costs

Linear costs increase the cost of construction to account for items that are proportional to the length of the route.

To enter or edit these costs, select the Linear tab:

Linear costs are applied to the entire length of the centreline that falls within a linear cost zone. The cost affecting an area can be linked to a Linear Cost Zone object; refer to Linear Cost Zones.

Fixed costs

Fixed costs do not affect the alignment optimization but are included to ensure that the final cost estimates do not omit significant cost items.

To enter a list of named fixed cost items, select the Fixed tab, right-click the table, and select New:

To apply the linear cost types create a Global Linear Cost Zone or a Local Linear Cost zone and select the area cost type.

Next topic: Structure Costs