A pile-driving record (also called a driving log) is the logbook in which, for every pile, it is recorded how many blows are needed to drive the pile a set distance into the ground. It serves as proof that each pile has reached the required load-bearing layer.
What is recorded?
For each pile, the pile-driving foreman or measuring system notes:
- Pile number and position — linked to the pile plan
- Blow count — the number of blows per decimetre or metre of penetration
- Final set — the settlement during the last blows
- Driving depth — the depth reached relative to ground level or a datum
- Hammer weight and drop height — the energy of the pile hammer
Why is it important?
The deeper the pile goes and the higher the point resistance becomes, the more blows are needed for the same penetration. This increase confirms that the load-bearing sand layer has been reached. If the blow count stays too low, the layer may not have been reached.
Application
The pile-driving record is used for:
- Bearing capacity check — comparison with the calculated value from the cone penetration test
- Handover documentation — proof for the structural engineer and client
- Problem analysis — for deviating piles
- Adjusting the pile plan — sometimes extra piles are driven
Related terms
- Pile
- Pile-driving rig
- Bearing capacity of a driven pile
- Cone penetration test
- Pile foundation
- Pile plan
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