Geotechnical Society of Singapore (GeoSS) has established specific draft guidelines and standards for the installation of jacked foundation piles . These practices focus on termination criteria jacking forces verification through set criteria
to ensure load-bearing capacity while minimizing environmental disturbance. Course Hero Core Installation Practices
The installation of jacked piles in Singapore typically follows these standard technical procedures: Jacking Force Application : The pile is jacked into the ground with a force ( cap P sub j ) usually adjusted to 2 to 2.5 times the working load (WL) Termination Criterion
: Piles are considered "set" when the downward movement does not exceed while holding the maximum jacking force for at least 30 seconds Verification Cycles
Once practical refusal is reached, the jacking force is released to zero.
It is then re-applied without pause to measure the "set" (downward movement). recommends achieving two consistent sets before terminating the installation. Verticality and Stability Minimum factor of safety against geotechnical failure = 2
: This method is favored in Singapore for its superior pile verticality and high machine stability compared to traditional driving methods. Course Hero Design and Site Considerations Subsoil Variations
: Designers must specify penetration depths based on site investigation (SI) boreholes. However, in Singapore, most specify the jacking force and set criterion on the piling plan as the primary termination metric. Floating Boulders
: In areas with "floaters" (boulders), pre-boring is often necessary to ensure piles reach the intended founding layer and avoid uneven settlement or overstressing. Load Testing : Performance-based designs are often verified using instrumented maintained Ultimate Load Tests (ULT) to optimize pile parameters on-site. Course Hero Safety and Regulations Equipment Certification
: Specialist builders must own a minimum number of primary piling base machineries (jacking machines and accessories) to meet Singapore’s certification criteria. Load Test Guidelines : GeoSS also provides specific Guidelines on Good Practices for Pile Load Test which cover the safe setup of the Kentledge method
, ensuring the massive deadweights used for testing do not pose hazards to workers or nearby structures. Singapore Accreditation Council specific geotechnical standards presence of boulders
(like SS CP4 or Eurocode 7) that govern these designs in Singapore?
Title: An In-Depth Review of "Good Practice for Installation of Jacked Foundation Piles in Singapore" (GEOSS Guide)
Rating: ★★★★★ (Essential Reading for Geotechnical Practitioners)
Reviewed by: [Your Name/Designation]
| Parameter | Good Practice Limit | GEOSS Trigger (Action Required) | |-----------|--------------------|----------------------------------| | Jacking rate | 0.5 – 1.5 m/min | >2 m/min (reduce rate, check hydraulic oil temp) | | Max jacking force | ≤ 80% of pile structural capacity | >85% – stop jacking, assess toe damage | | Heave of adjacent ground | < 10 mm | 10–25 mm – reduce jacking rate; >25 mm – stop, grout relief holes | | Pile verticality | < 0.5% deviation | >1% – de-jack, re-align; >2% – abandon pile | | Hydraulic pressure spike | < 15% of steady pressure | >15% – inspect pile head & shoe | old timber piles
In soft marine clay, jacking multiple piles can cause surface heave of 50–100 mm, damaging nearby buried utilities.
GEOSS Solution: Limit jacking rate to 2 mm/s in clay and install relief slots or pre-drilled guide holes.
Singapore’s urban landscape is a testament to advanced geotechnical engineering. With land scarcity driving developments both skyward and below ground, the demand for robust, low-noise, and low-vibration foundation solutions has never been higher. Among the various piling techniques, jacked piling (also known as silent piling or hydraulic jacking) has emerged as a preferred method for installing displacement piles in dense urban environments.
However, improper jacked piling can lead to ground heave, lateral displacement of adjacent piles, damage to existing structures, and even pile refusal. To address these challenges, the Geotechnical Society of Singapore (GEOSS) has published a definitive framework known as the GEOSS Good Practice for Installation of Jacked Foundation Piles in Singapore.
This article provides a comprehensive breakdown of that good practice guide, offering engineers, contractors, and project managers a direct link between theoretical design and site execution. For the official GEOSS document, refer to the link provided at the end of this article.
GEOSS is currently drafting an addendum to the good practice guide addressing:
These updates will be linked to Singapore’s Smart Nation initiative for digital twinning of underground infrastructure. The key takeaway: the "GEOSS good practice" is a living document—practitioners should check the official link quarterly for revisions.