What we Do
Why
Cable percussion drilling or site investigation (S I) drilling is necessary to determine a depth and description of the geological strata in specific locations, on land and (occasionally) on water. Generally S I Drilling is required for engineering purpose with a myriad of objectives. Essentially these objectives are to obtain soil samples and consequently results from boreholes drilled in the field. The results inform our clients of the necessary steps needed to determine foundation solutions in substructure and infrastructure design and development. Geotechnical, geoenvironmental, geological and hydrological information that can only come from the ground benefits people, property and the environment. Boreholes can also be drilled for water extraction i.e. drinking water and irragation.
What
Cable percussion drilling is the most common and cost effective method of obtaining soil and water samples for analysis. These samples are extracted and can be delivered in different forms, including:
- UT100/U100 metal/plastic tubes
- Small sample bags at 250x375mm
- Larger sample bags at 450x600mm
- Plastic tubs at various sizes
- Glass jars for environmental uses
- Plastic or glass bottles for water samples
These are taken insitu by the drill team and passed on to the client along with a hand written log which describes the borehole drilled. Wells can be installed for geotechnical and environmental testing and monitoring. Standard Cable percussion drilling uses a mobile drilling rig with a two to three tonne capacity winch towed by a 4x4 vehicle to the borehole position. The winch is powered by a diesel/electric powered engine. The rig is erected via an electric winch, the rig stands at approx 6.5m high. On projects that have restricted headroom or access limitations the ‘low-headroom’ or ‘de-mountable’ rig can be utilised. These rigs are mobilised to site by on a trailer and Transit van.
When
S I Drilling Cable Percussion Ltd is open for business 365 days of the year Week end, night work and bank holidays are subject to higher rated charge
Where
S I Drilling Cable Percussion Ltd are prepared to travel! We work UK wide. Past projects we have travelled to Isle of Man, Guernsey and Jersey. We have also worked in Belgium France and Malta. S I Drilling Cable Percussion Ltd are based in Norwich Norfolk. Mobilisation charges, which is on our Schedule of Rates, includes one string of drill casing transported to site within a 150 mile radius of Norwich.
How
Before a borehole can be drilled our client has to ensure access and working space is suitable. In some cases landowner consent / permits/ signage/ fencing or traffic management in place We need a site instruction and possibly a site induction from our client. We mobilise to site on agreed date to arrive at the agreed time. The borehole will be progressed by forcing the hollow steel casing into the ground to prevent collapse and isolate the borehole from the surrounding soils. By using different drilling tools the material within the casing is removed. The casing is then progressed to a greater depth and the process repeated. Casing lengths are added as required until the required depth is achieved and soil samples retrieved. A borehole log describing the borehole is drawn up by the driller as soon as possible after the completion of the borehole. This will contain full details about the project, including all sampling and in-situ testing details. If a monitoring well is required, this will be installed before removal of the steel casing. This usually takes the form of UPVC or HDPE 50mm diameter slotted or plain plastic pipe. A gravel surround is placed around the pipe with a Bentonite seal at the surface. This will be done in connection with any specific instructions that the client may require. A suitable cover will be concreted in at the surface for future access. If there is no requirement for a monitoring well, the borehole will be backfilled in accordance with the project specification. All excess material will be removed from site by the driller and the working areas left as clean and tidy as is reasonably practicable. Client specifies what to done with the Soil samples