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

| Formation | Characteristics | Jacked pile suitability | |-----------|----------------|------------------------| | Marine Clay (upper/lower) | Soft to firm, high compressibility | Good – full displacement helps densify | | Kallang Formation | Soft clay, peaty layers, sands | Good with sleeve or lubrication | | Old Alluvium | Dense to very dense, silty sand | Difficult – may need pre-boring or limited depth | | Jurong Formation | Weathered sedimentary rock | Requires shoe and high jacking force |

✅ Good practice: Always verify against CPT/SPT data – jacking into Old Alluvium > SPT 100 may stall the rig.

This is the core of the "Good Practice" guide, covering: | Formation | Characteristics | Jacked pile suitability

GEOSS defines termination not by a single number but by a three-part rule:

Prohibited action: Do not attempt to achieve refusal by suddenly increasing hydraulic pressure. That cracks piles. ✅ Good practice: Always verify against CPT/SPT data

Jacked piles offer an efficient, low-disturbance foundation solution for Singapore’s urban environment when installed using GEOSS good practice. Critical success factors include: continuous monitoring of jacking force, strict verticality control, limiting jacking rate in clay, and pre-boring for Old Alluvium or bouldery ground. Adherence to this practice minimizes risks to adjacent structures, ensures pile integrity, and meets regulatory requirements from BCA, LTA, and NEA.

References

Prepared by: GEOSS Technical Committee – Pile Installation Working Group
Disclaimer: This paper is a good practice guide, not a legal document. Site-specific design by a Professional Engineer (Civil/Geotechnical) registered in Singapore is required.

In Singapore, the governing document for this topic is GEOSS Guide 7: Good Engineering Practice for Installation of Jacked Foundation Piles. This is the core of the "Good Practice"

Here is a comprehensive report summarizing the key aspects of this guide, its context within Singapore regulations, and its technical requirements.