Cable percussion boreholes are an intrusive geotechnical site investigation technique used to determine the ground conditions of a site. It’s probably one of the most popular forms of drilling used across the world; and it’s easy to see why! Cable percussion drilling (CPD) is extremely reliable and versatile, making it a firm favourite amongst geotechnical companies.
Unfortunately, Borehole Solutions couldn’t tell you how many CPD projects they have carried out over the years… because they’ve lost count! This is why our expert team would like to talk about why this method of drilling is so popular.
How does CPD work?
Cable percussion drilling, also known as shell and auger drilling, can be used to drill boreholes of up to 60 metres deep. A cable percussion rig has a large tripod and winch to repeatedly raise and lower the heavy cutting tool inside a steel casing tube. This casing is used to maintain stability as well as prevent the borehole collapsing from any loose soil. Different cutting tools are used dependent on the type of ground and subsurface.
What is CPD used for?
Cable percussion boreholes allow us to retrieve both disturbed and undisturbed samples at regular intervals. These retrieved samples can then undergo laboratory testing to assess the soil structure and test for contamination. The results are used to establish the ground conditions or equipment can be installed for ongoing measurements, such as gas and groundwater monitoring.
The boreholes can be used for a variety of tests, including:
- Standard penetration testing (SPT)
- Cone penetration testing (CPT)
- Permeability testing
- Borehole vane testing
What are the benefits of CPD?
Cable percussion boreholes have proven their worth time and time again. Their simplicity, especially when considered alongside the high-quality results, plays a key role in explaining why this method is so popular. Here are some benefits of CPD…
One of the main benefits to using cable percussion drilling rigs is that they can be transported easily. They’re easy to dismantle, allowing them to be moved by a 4×4 vehicle with ease. This means they can be transported around the country wherever they’re required, which is a huge bonus!
Furthermore, their distinctive tripod leaves minimal impact on the surrounding environment; which is a big incentive to any eco-conscious geotechnical company.
Whilst the rig itself is relatively large, their crane attachments allow them to be lifted into position, if necessary.
As cable percussion boreholes are used so extensively, they have been made as efficient as possible. Not only in terms of finances, but also time. Borehole Solutions provide our clients with not only a competitive quote, but also extensive industry experience to ensure you have the best possible outcome.
Whilst the borehole is being advanced downwards, the drilling can be paused at any time to carry out testing as required. This could involve anything from SPT to permeability testing.
In addition, this drilling method can be used on a wide range of ground types; including hard rocks and cohesive soils. For looser substrates, casings can be used to maintain the structural integrity during drilling. Consequently, this means that very few substrates are unable to be tackled by CPD rigs!
If you’re interested hearing more about cable percussion boreholes or want to know more about our services, then please get in touch! Give us a call on 01733 200501 or click here to speak with us directly.