Urban density heavily restricts construction methods in Singapore. Traditional driven piling methods generate excessive noise and ground vibrations. This threatens adjacent mass rapid transit (MRT) tunnels, utilities, and high-rise structures.
| Mode | Condition | Objective | |------|-----------|------------| | Force control | Soft to medium stiff clay (N < 15) | Maintain constant jacking force, record penetration rate (mm/min). | | Rate control | Dense sand / Old Alluvium (N > 30) | Limit penetration rate to < 5 mm/sec to avoid excessive load spikes. | | Stroke control | Final set-up (refusal) | Advance in 50 mm strokes; record final jacking pressure at each stroke. |
For high‑rise buildings underlain by thick layers of soft clay deposits, pile heave and settlement risks are elevated. Mitigation measures include:
To ensure that driven or jacked piles are installed properly, a as tabulated in Appendix A of the circular is adopted. Depending on the classification of the building, requirements include: | For high‑rise buildings underlain by thick layers
7.3 Acceptance Criteria
stems from minimal environmental impact (low noise and vibration) and cost-effectiveness. Installation must strictly adhere to and specific local practices to ensure safety and structural integrity . Key Installation Practices & Termination Criteria
High-frequency recording of jacking force—typically at every 0.5 m to 1.0 m of penetration—is recommended for quality assurance. isomer-user-content.by.gov.sg Load Testing Standards GEOSS defines three control modes:
Ensure the centerline of the extension pile aligns perfectly with the driven segment to avoid eccentric loading. Monitoring, Instrumentation, and Quality Assurance Data-driven verification is central to GEOSS guidelines. Real-Time Instrumentation
Singapore's spatial geology varies widely, demanding adaptive engineering during the jacking process.
| Standard | Title | |----------|-------| | | Geotechnical design – General rules | | BCA “Piling” CP 4 (historical reference) | Still referenced for workmanship | | SS EN 12699 | Execution of special geotechnical works – Displacement piles | | LTA Civil Design Criteria | For transport infrastructure projects | jacked piles allow .
Never adjust a pile’s alignment by force during the jacking process; this can compromise the structural integrity of the pile. Strategic Jacking Sequence: For large pile groups, always work from inside out
Successful installation begins with a thorough understanding of the site’s soil profile to prevent damage to adjacent structures.
) is typically related to the ultimate geotechnical capacity ( cap P sub u ), often set at 2.0 to 2.5 times the working load (WL) Set Criterion:
For the full GEOSS document (2021 edition) and the latest addendum on jacked piles, visit the Singapore Society for Geotechnical Engineering (SSGE) portal.
Unlike impact hammers, jacked piles allow . GEOSS defines three control modes: