Piles In Singapore - Geoss Good Practice For Installation Of Jacked Foundation
Title: GEOSS Good Practice for Installation of Jacked Foundation Piles in Singapore
Document ID: GEOSS-GP-JP-2026
Revision: 1.0
Date: April 2026 Title: GEOSS Good Practice for Installation of Jacked
Part 2: GEOSS Core Principles for Jacked Pile Installation
The GEOSS Good Practice Guide for Pile Foundation (revised 2021) outlines five pillars specifically for jacking: Scenario: Jacking through dense sand lens above clay
4.2 Jacking Equipment & Rig Selection
| Pile type | Typical jacking force | Rig type |
|-----------|----------------------|-----------|
| 200x200 mm RC pile | 1,500 – 2,500 kN | Small hydraulic rig (e.g., Yoke type) |
| 300x300 mm RC pile | 3,000 – 4,500 kN | Medium tracked rig |
| Steel pipe (OD 406 mm) | Up to 6,000 kN | Heavy reaction rig with anchor piles | NDT (UT) on 10% of splices.
Good practice: Calibrate jacks every 6 months or after 10,000 cycles. Maintain digital record of jack pressure vs. force.
Failure 3: False Set (Arching in Sand)
- Scenario: Jacking through dense sand lens above clay.
- Violation: Operator mistook temporary high resistance for refusal.
- Result: Pile terminated prematurely; later settlement occurred.
- GEOSS Solution: If resistance spikes >80% of jack capacity, wait 2 minutes for pore pressures to dissipate. Re-jack. If force drops by >20%, continue – this was arching, not refusal.
4.3 Pile Handling & Alignment
- Verticality tolerance: ≤1:200 (0.5%) for ordinary structures; ≤1:300 for MRT viaducts.
- Checks: Digital inclinometer on pile every 3 m during jacking.
- Splicing (if required):
- RC piles: epoxy-coated welded end plates with full penetration weld.
- Steel piles: full penetration butt weld, NDT (UT) on 10% of splices.