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Probing the Depths – Part Two

The headline “ground swallows car” sounds as if it comes straight out of a Hollywood horror film. But it is actually surprisingly common in areas with either chalk or limestone geology or with a history of mining (which could be for clay or salt as well as for coal).

If you are considering constructing foundations you may wish to consider commissioning us to ‘pile probe’ the area first. Not only will this identify shallow obstructions but it will identify swallow holes, solution features and abandoned underground workings such as the ones that caused this:

Ground Swallows Car

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Probing the Depths……

Pile Probing Rig

…of Central London in this case. Subadra has completed a week of pile probing at a cramped development site in Central London. Despite obstacles such as leaking water mains, piling rigs and deep excavations we successfully probed sixty locations to verify the presence of below ground obstacles that might impede the construction of the engineers’ piled foundation solution and contiguous boundary piles. The contractor used this information to target additional ground clearance the key areas of concern.
Contract value: <£5k

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Foundations for Key City Data Centre

Whilst much of our work in carried out in the provinces we sometimes dabble with high finance in the City.

Subadra played a key role in the development of an £80 million multi-storey data centre facility in London’s docklands area. We were brought in at the inception of the project to carry out a geotechnical and environmental investigation to determine ground conditions.

Our investigation comprised a network of boreholes across the development area that were used to collect soil samples for analysis and groundwater and hazardous gas monitoring points.

The site was especially tricky geotechnically, comprising areas of in-filled docks, some highly contaminated and others containing very soft silts and clays.

We used the data to assist with foundation design and the classification of waste soil.

Contract value: £20-50k

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Pile Probing for Five Star Hotel

Encountering obstructions during piling works and clearing these obstructions can cause significant cost implications and also impact upon the construction programme. However, delays and significant cost-overuns can be avoided by completing a quick and easy pile probing survey.
We recently carried out a pile probing exercise a high profile redevelopment project in central London. The principal contractor identified an old, below-ground fuel tank that needed to be removed. Due to adverse ground conditions and proximity to a basement and the adjacent road, sheet piling around the tank prior to its removal was considered the most effective and safest option.
We were brought in prior to the piling rig to identify an obstruction free boundary around the tank to allow the piling to be undertaken. We completed 400m+ of probing in two days using our Geoprobe drill rig, completing the works on budget and ahead of schedule.
Additionally, despite the working area having been surveyed and declared “service-free” by the principal contractor our drill team, who are all trained in service detection, identified a 4″ water main in our specified working area during our pre-enabling The findings from our probing allowed the pile design to be refined and the service clearance works we carried out avoided everyone from getting very wet.
Contract value: <£10k

See also: Mayfair Hotel