Jacked-in pile foundation systems have become a preferred choice for urban development in Singapore due to their low vibration, minimal noise, and high load-bearing capacity. The Geotechnical Society of Singapore (GEOSS) emphasizes stringent "good practice" guidelines to ensure structural integrity and compliance with Eurocode 7, especially given Singapore's complex geological conditions, including the weathered sedimentary rocks of the Jurong Formation and variable marine clays.
When an obstruction (boulder, old foundation, etc.) prevents pile penetration, the following options exist:
Piling work must be supervised by competent and suitably qualified persons with comparable experience, as required by BS EN 12699. The site supervisor’s responsibilities include:
Verticality must be monitored, typically requiring a deviation of no more than . Ground Considerations & Risk Management Jacked-in pile foundation systems have become a preferred
: The jacking force is released to zero and re-applied without pause to confirm the "set." Two consistent sets are recommended for final termination. Geotechnical Assessment
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:
In areas with steeply inclined bedrock or potential voids, extra caution and probe holes at every pile group location are advised to establish proper acceptance. Machinery & Quality Control and yearly checklists
Rigorous maintenance regimes, including daily, monthly, and yearly checklists, are mandatory to ensure machines are in good condition.
The pile alignment should be adjusted by force during installation.
No amount of construction expertise can compensate for inadequate ground characterisation. The joint establishes mandatory requirements for ground investigation, load testing, and quality control tests for foundations of buildings of 10 storeys or more, and buildings of 5 to 9 storeys with a footprint larger than 100m². For jacked piles specifically, a thorough site investigation must address: especially given Singapore's complex geological conditions
Sonic integrity testing checks for cracks or discontinuities in concrete piles caused by high jacking stresses. Conclusion
Piling work must be supervised by competent and suitably qualified persons with comparable experience (BS EN 12699). “Lack of quality assurance and quality control by contractors and lack of proper site supervision by suitably qualified engineers” is commonly cited as one of the major causes for project problems/failures (delay, cost overrun, distress, etc.).