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CPT Testing in Newbridge – Fast, Accurate Soil Stratigraphy

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Newbridge sits on the edge of the Curragh plain, an area defined by its glacial history. This means the ground beneath the town is not uniform. You find dense tills deposited by ice sheets right next to pockets of soft alluvium along the River Liffey. A standard trial pit often cannot reach the depths needed for a commercial foundation here. We run the CPT to map these drastic changes continuously. The 20-tonne rig pushes a cone through the soil, measuring tip resistance and sleeve friction in real time. For projects near the Whitewater Shopping Centre or the expanding industrial estates, this data is essential. It helps engineers avoid surprises when they hit a loose lens of sand at depth. We have seen standard borehole logs misrepresent the actual layering by up to 20 percent in this area. Combining a CPT profile with a targeted Sondaje SPT campaign confirms the soil parameters needed for a safe design.

We push the cone until refusal or until we have the data the client needs. No guesswork, just a continuous log of the ground.

Our service areas

How we work

Our field procedures follow the guidelines set out in Eurocode 7 (EN 1997-2:2007) and the Irish Ground Investigation Specification. In Newbridge, we often encounter boulder clays that challenge standard rigs. We deploy a heavy-duty truck-mounted unit to push through these dense materials without buckling the rods. The cone measures porosity, estimates the undrained shear strength in clays, and flags potential problems like overconsolidation. The data comes in as a continuous log, not just split-spoon intervals. For sites on the southern side of the town, where the ground transitions toward the Wicklow granite, we often pair the cone with a geophysical survey to see the top of bedrock clearly. We also recommend a soil suction test when the project involves deep basements in the silty zones. The rig is calibrated before every job and we check the zero load every morning. You get reliable repeatability from the first push to the last.
CPT Testing in Newbridge – Fast, Accurate Soil Stratigraphy
Technical reference — Newbridge

Local considerations

We still see some site investigations in Newbridge that rely solely on trial pits. That is a mistake when the water table is high. An excavator hits the groundwater at two metres and the pit collapses. The log says 'end of investigation' but the foundation goes down to four metres. You have zero data on the critical bearing layer. We see this regularly on the floodplain near the Liffey. Using a CPT, we push through the water-bearing silt and get readings in the dense gravel below. It takes a single morning. The biggest risk is designing a pad footing on assumed strength values that do not exist. A cone refusal at shallow depth tells you immediately that the design needs a revision. We also flag soft clay layers that can settle differentially under load. Ignoring these thin layers is the most common cause of floor slab cracking in the industrial units around the town.

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Email: contact@geotechnical-engineering.co

Applicable standards

IS EN ISO 22476-1:2012 (Geotechnical investigation and testing – Field testing – Part 1: Electrical cone and piezocone penetration tests), Eurocode 7 (EN 1997-2:2007) – Ground investigation and testing, UK Specification for Ground Investigation (ICE, 2nd Edition), commonly referenced in Irish practice

Technical data

ParameterTypical value
Maximum push depth in tills20 m (varies with boulder content)
Cone tip capacity100 MPa (standard)
Sleeve friction range0 to 1 MPa
Pore pressure transducerYes, for piezocone (CPTu) profiles
InclinometerIntegrated, measures rod tilt
Data logging intervalEvery 10 to 20 mm depth
Reporting standardIncludes normalized charts and soil behavior type

Common questions

How much does a CPT test cost in Newbridge?

The cost for a standard CPT profile in Newbridge runs between €160 and €260 per test point, depending on the depth and access conditions. A deeper push in dense glacial till that requires a heavy rig will be at the upper end. We provide a fixed quote after reviewing the site location and the target depth.

Can you do a CPT if there are boulders in the ground?

We can attempt it with our heavy rig, but boulders are a risk for any cone. We use a sacrificial tip and if we hit a boulder, we stop the push at that depth. We then note the refusal and advise on a complementary borehole to core through the obstruction.

What is the difference between a CPT and a standard trial pit?

A trial pit gives you a visual look at the soil but only goes down 3 to 4 metres. A CPT provides a continuous log of the soil strength down to 20 metres or more. It gives you numbers for bearing capacity and settlement that a pit log cannot provide.

How long does the test take on site?

For a single push to 15 metres in the soils found around Newbridge, we can complete the test in 45 to 60 minutes. If we run dissipation tests to measure the water pressure response, it adds about 20 minutes per test depth.

Location and service area

We serve projects in Newbridge and surrounding areas. More info.

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