For Installation Of Jacked Foundation Piles In Singapore ~upd~ | Geoss Good Practice

| Defect | Likely Cause | GEOSS Recommended Action | | :--- | :--- | :--- | | Sudden drop in jacking force (≥20%) | Pile fracture or soft pocket | Stop, extract if possible, install replacement pile. | | Refusal above design depth (≥1 m) | Boulder / old timber pile | Use pre-boring (300 mm dia.) to 500 mm below refusal depth, then re-jack. | | Excessive heave (>25 mm) | Rapid jacking in clay | Restrike all piles within heave zone after 7 days. | | Verticality drift > 1:100 | Inclined bedrock or poor jig | Install raking micro-piles as supplement. |

Because jacked piles are displacement piles, they can cause significant ground heave. Protecting nearby buildings is a requirement: Relief Wells: | Defect | Likely Cause | GEOSS Recommended