Page 14 - GDL - EARTHWORKS GROUND IMPROVEMENT PILING

ROTARY BORED PILING
Rotary Bored Piling is carried out by our Large Diameter Piling (LDP) rigs which offer higher power (torque) than our CFA rigs so they are more agile and able to overcome underground obstructions.
When constructing rotary bored piles we have the ability to quickly change coring or digging tools and auger type to best
suit soil conditions. We can also install plunge columns in the pile to facilitate top-down construction. Compared with other piling techniques LDP can offer larger load capacities and be installed to far greater depths.
Drilling technique: Rotary bored piles are constructed by rotating a casing into the ground to support poor or granular ground and then removing the pile bore using an auger, bucket or coring unit attached to a telescopic Kelly bar. Once the bore is fully cleaned out to design depth, the pile concrete is tremied into the bore and the casing is extracted leaving a nished pile. Typically, pile reinforcement is cast into the pile during concreting.
Ground conditions: Rotary piling can be employed in almost all ground conditions from soft ground supported by temporary casing through to high grade very strong rock cored in to open-hole techniques.
Advantages of Rotary Bored Piling:
• Amenable to almost all ground conditions including rock drilling
• Depths achievable up to 60m with casing and tool diameters up to 1.8m means that very high capacity loads can be achieved
• Minimal ground disturbance and vibration – resulting risk to adjacent structures and property is limited
• Simple and ef cient installation process
• Ability to construct sockets into underlying rock
• Larger diameters feasible
• Can extend to greater depths when compared with any
other piling technique