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Section 3: Highway construction |
1 Earth Science Systems Ltd, 1 Barnfield Court, Harpenden, Herts AL5 1DA, UK
2 Fugro Ltd, 18 Frogmore Road, Hemel Hempsted, Herts HP3 9RT, UK
Recent increased expenditure on water supply infrastructure has involved the construction of many underground pipelines in a variety of geological situations. Variations in ground conditions not revealed by site investigation boreholes have sometimes led to major cost implications.
It is suggested that geophysical surveys along planned pipeline routes before construction can assist in highlighting potential problem areas and lead to the cost-effective location of site investigation boreholes.
Background
In many instances the route of a new pipeline is constrained by significant factors such as land access, topographic variations along the route and local planning conditions.
The geological conditions along the route are often relegated to a minor consideration to be determined by a few shallow boreholes after the route has been almost decided and land access provisionally agreed. These boreholes or trial pits are often conveniently sited at regular intervals along a pipeline route. Unfortunately, the geological conditions are often variable and carry with them cost implications. Typical examples are when a sandstone which can be easily ripped by a machine changes laterally into a more durable lithology which requires blasting, or when the depth of soil cover overlying the bedrock decreases sharply, requiring a change in the type of excavator used.
In the selection of any pipeline route an initial desk study is carried out by engineers and planners, who collate all the available relevant information.
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This 250-word extract was created in the absence of an abstract.
