OR/14/001 Using the dataset

Dearden, R A, Tye, A M and Marchant, A. 2013. User Guide for the corroded Asset failure. British Geological Survey Internal Report, OR/14/001.

GIS set-up

Load the layer files or shape files into the GIS software. We recommend importing the layer file (if using ArcGIS) as this ensures that the colour and layout of the layers appear as intended. For other GIS packages, import the layers manually. A .CSV file is provided with the recommended legend colours. The GIS should appear as shown Figure 1. Make sure the required data layer is present. For the summary map, the following GIS layer should be present:

• Ferrous_failure_summary

For the detailed map, the following GIS layer should be present:

• Ferrous_failure

If you need support setting up the GIS, please contact digitaldata@bgs.ac.uk.

Pan to a location of interest and view each dataset sequentially, following the flow chart in Figure 3.

Figure 3    How to use the ‘ferrous_failure’ GIS layer.

Explanation of sub-layers

Explanations of the field descriptions for the ‘ferrous_failure’ summary field are provided in Table 1. Explanations of the descriptions in the corrosivity, compress, swell, collapse, runsand, landslide and soluble sub-layers are provided in Tables 2 to 8.

Table 1    Summary sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corrosive ground conditions and ground instability are unlikely to occur simultaneously and thus it is unlikely that corroded ferrous assets will fail due to ground movement. Note that iron corrosion can occur in all soils, but the aggressiveness of the soil is unlikely to be enhanced in these areas.
Low	Corrosive ground conditions and ground instability may occur and thus there is a low potential that corroded ferrous assets will fail.
Moderate	Corrosive ground conditions and moderate ground instability may occur and thus there is a moderate potential that corroded ferrous assets will fail.
High	Corrosive ground conditions and potentially significant ground instability may occur and thus a higher potential that corroded ferrous assets will fail.

Table 2    Corrosivity (Corrosiv) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Ground conditions beneath top soil unlikely to cause corrosion to iron
Possible	Ground conditions beneath top soil may cause corrosion to iron
Likely	Ground conditions beneath top soil are likely to cause corrosion to iron

Table 3    Compressibility (Compress) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to be affected by compressible ground.
Low	Low potential for corroded underground assets to fail due to this hazard. Slight possibility of compressible ground.
Moderate	Moderate potential for corroded underground assets to fail as compressible ground is probably present.

Table 4    Shrink-swell (Swell) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to fail due to shrink-swell clays as the ground has low plasticity.
Low	Low potential for corroded underground assets to fail due to this hazard. Medium plasticity shrink-swell clays present, but may not result in ground movement.
Moderate	Moderate potential for corroded underground assets to fail as high to very high plasticity shrink-swell clays are present, and likely to cause ground movement.

Table 5    Collapsible deposits (Collapse) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to be affected by collapsible ground.
Very low	Very low potential for corroded underground assets to fail due to this hazard. Deposits with the potential to collapse may be present.
Low	Low potential for corroded underground assets to fail due to this hazard, although collapsible deposits are present.

Table 6    Running sands (Runsand) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to be affected by running sand.
Very low	Low potential for corroded underground assets to fail due to this hazard. Slight possibility for running sand conditions.
Low to moderate	Low to moderate potential for corroded underground assets to fail as running sand conditions are probably present.

Table 7    Landslides (lndslide) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to be affected by landslides.
Low to moderate	Low to moderate potential for corroded underground assets to fail due to this hazard. Slope instability problems may be present.
Moderate to high	Moderate to high potential for corroded underground assets to fail as slopes have a significant to very significant potential for instability.

Table 8    Dissolution (soluble) sub-layer — Description of attributes.

Attributes	Definition
Unlikely	Corroded underground assets unlikely to be affected by subsidence resulting from dissolution of rocks.
Low	Low potential for corroded underground assets to fail due to this hazard. Soluble rocks are present, but there is a low possibility of dissolution-induced subsidence.
Moderate to high	Moderate to high potential for corroded underground assets to fail as there is a moderate to high possibility of localised subsidence resulting from dissolution.