GEOSS mandates that all jacked piling rigs used in Singapore for projects > 5 storeys must have automated data acquisition:
This is the core of the "Good Practice" guide, covering:
Jacked piles are not immune to defects. The good practice mandates 100% low-strain integrity testing (PIT) using a pulse echo method, performed between 3 to 14 days after installation. For high-rise projects (>30 stories), high-strain dynamic testing on 2% of piles (min. 2 piles) is required using a drop weight – not a hammer – to avoid damaging the pile. GEOSS mandates that all jacked piling rigs used
Acceptance criteria:
Manual recording is no longer sufficient for Category III works. Good practice mandates: Manual recording is no longer sufficient for Category
GEOSS submission: PIRs and summary sheets must be endorsed by the RE within 24 hours and available for audit.
The GEOSS Good Practice Guide for Pile Foundation (revised 2021) outlines five pillars specifically for jacking: GEOSS submission: PIRs and summary sheets must be
Not all piles can be jacked. GEOSS specifies:
| Problem | Cause | Good Practice Solution | |---------|-------|------------------------| | Pile refuses before design depth | Dense sand layer / Old Alluvium | Pre-bore 50–70% of pile depth; use shoe; reduce spacing of reaction piles | | Pile cracks during jacking | Tensile bending during eccentric load | Reduce rate; install centralizing guide; reject pile if crack >0.2 mm | | Adjacent ground heave | Full displacement in clay | Re-jack perimeter piles; install relief holes (100 mm dia., 2 m deep) | | Jacking force drops suddenly | Void / old trench backfill | Stop, inject grout, re-jack next day with lower rate | | Neighbour complaint (vibration) | Even jacking has micro-vibration | Use rubber pad at pile head; monitor with PPV <5 mm/s |
