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

The Geotechnical Society of Singapore ( GeoSS ) has established specific guidelines for the installation of jacked foundation piles to ensure structural safety and serviceability within Singapore’s unique geological landscape. Jacked piles are favored in urban areas due to their , negligible vibration , and minimal soil disposal . 1. Pre-Installation and Ground Considerations

The of your project site (e.g., Kallang Formation clay vs. Bukit Timah granite).

Introduction Jacked foundation piles (hydraulically driven displacement piles and pre-bored jacked piles) are widely used in Singapore for deep foundations where vibration minimization, tight site access, and load performance are critical. Singapore’s reclaimed land, alluvial deposits, marine clay layers, and dense urban fabric require tailored procedures to mitigate settlement, ground disturbance, and risks to nearby structures and utilities. This paper outlines GEOSS Good Practice covering site investigation, pile selection and design, installation methodology, instrumentation and monitoring, quality control, environmental and safety management, and post-installation validation.

Accurate, real-time logging of jacking pressure, pile depth, and time is crucial for QC. Summary of GEOSS Best Practices Action Area Good Practice Principle Site Prep Conduct probe holes at all pile locations to map cavities. Handling Never force alignment during jacking. Installation Maintain constant verticality checks. Sequence Jack in an inside-out sequence for groups. Pressure Use 2–2.5 times WL and re-apply load at refusal. The Geotechnical Society of Singapore ( GeoSS )

The hydraulic rams apply a steady, continuous downward force. Halting the process prematurely inside sandy strata can cause soil setup, drastically increasing the force required to restart movement and risking premature pile refusal. Step 4: Jointing of Pile Segments

The high compressive forces exerted during hydraulic jacking require premium materials and calibrated machinery.

Jacked piling is a displacement piling method. Hydraulic jacks press prefabricated piles into the ground using deadweight counterweights (kentledge). Key Benefits in Singapore's Context When multiple machines are on-site

Installing jacked piles in Singapore requires navigating complex geologies. These include the soft marine clays of the Kallang Formation and the highly weathered profile of the Bukit Timah Granite.

Implement systematic pre-boring at the pile point or install relief wells to release excess pore water pressure.

Conduct high-resolution pre-bore probing. Utilize pre-boring methods to loosen hard intermediate layers before jacking. continuous downward force.

When multiple machines are on-site, they should not be clustered closely together, as this aggregates ground movement risks. Open Trenches:

GEOSS Good Practice for Installation of Jacked Foundation Piles in Singapore Introduction

To protect sensitive nearby buildings from ground movement caused by displacement piles, practitioners may use: Relief wells or pre-boring at the pile point. Open trenches or temporary earth-retaining walls.