Bored Piles

Large diameter bored piles installed with Kelly telescopic bars for deep foundations with high load capacity.

Overview

Bored piles (Kelly) are one of the most versatile and widely used solutions for deep foundations. This technology is based on rotary drilling performed with telescopic Kelly bars and interchangeable drilling tools, allowing the installation of large-diameter piles at significant depths.

The pile is constructed by drilling vertically into the ground, removing the excavated material and subsequently placing reinforcement and concrete into the borehole.

Depending on geological conditions and structural requirements, the hole can be executed:

Without casing
Partially cased
Fully cased
With the use of stabilising slurry (bentonite or polymer)

Kelly drilling technology ensures high adaptability to different soil profiles, from loose soils to hard rock formations, making it suitable for infrastructure, industrial and civil construction projects.

How it works?

Machine positioning and start of drilling

The piling rig is positioned and equipped with a telescopic Kelly bar and a rotary drilling tool such as a bucket, auger or core barrel.

Excavation and hole advancement

The tool rotates and penetrates the ground, extracting soil or rock material progressively until the design depth is reached.

Hole management and stabilisation

Depending on soil conditions, the borehole can be stabilised using temporary casing or stabilising slurry to prevent collapse.

Installation of reinforcement (if required)

A prefabricated steel reinforcement cage is lowered into the borehole to provide the required structural capacity.

Concrete pouring and finishing

Concrete is poured through a tremie pipe or directly into the hole, ensuring full displacement of slurry if present and complete filling of the shaft.

Advantages

✓ Geotechnical adaptability: suitable for a wide range of soils, from sand to hard rock
✓ Geometry control: precise diameters and adjustable depths even during construction
✓ High load-bearing capacity for heavy structures
✓ Flexible hole stabilisation methods (casing or slurry)
✓ Suitable for complex infrastructures and urban environments

Limitations

⚠ Generates excavation spoil that must be managed and transported
⚠ Longer cycle time compared to continuous technologies (e.g. CFA, FDP)
⚠ Requires proper hole stabilisation in loose or water-bearing soils
⚠ Larger site logistics footprint compared to displacement systems
⚠ Limited efficiency in highly unstable or fractured ground conditions

Compatible Casagrande equipment

CB16

Max. depth 57 m
Max. drilling diameter undermast 3000 mm
Max. drilling diameter uncased – Crowd cylinder 1800 mm
Max. drilling diameter uncased – Crowd winch 1500 mm
Max. diameter with casing oscillator 1300 mm

Bored Piles

Overview

How it works?

Machine positioning and start of drilling

Excavation and hole advancement

Hole management and stabilisation

Installation of reinforcement (if required)

Concrete pouring and finishing

Advantages

Limitations

Compatible Casagrande equipment

CB16

CB20

CB26

CB30

B200

B240

B250

B275

B300

B360

B400

B420

B470

C20

C30

C35

C40

Discover other Large diameter piles technologies:

Cased CFA

CFA piles

Displacement piles

DTH hammer

Maximum uptime. Continuous support.

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