Piles are typically jacked until they reach "practical refusal" at a force ( cap P sub j 2 to 2.5 times the working load ( cap W cap L
| Step | Action | Control Parameter | | :--- | :--- | :--- | | 1 | Lower pile into jig. | Eccentricity < 10 mm. | | 2 | Apply initial seating load. | 10% of working load (WL). | | 3 | Commence continuous jacking. | Rate: 0.5–1.5 m/min (max 2 m/min). | | 4 | Pause every 2 m for verticality check. | Deviation < 1:200. | | 5 | At termination: Hold for 30 s. | Pressure decay < 5%. | Piles are typically jacked until they reach "practical
Good practice involves rigorous control over the jacking process to ensure pile integrity and capacity: Capacity & Utilization | 10% of working load (WL)
Because jacking machines are heavy, the working platform must be high-quality, well-compacted, and have adequate site drainage. | | 4 | Pause every 2 m for verticality check
Research suggests that for piles where the depth is less than 37 times the diameter, the ultimate capacity ( cap P sub u ) may be less than the jacking force ( cap P sub j isomer-user-content.by.gov.sg Protective Measures for Adjacent Structures
7.2 Performance Testing
: Jacking machines in Singapore typically have capacities up to 800 tonnes . It is recommended to use machines at only 75% of their maximum capacity to maintain stability. Force Application : The pile is jacked with a force ( cap P sub j ) adjusted in steps, typically reaching 2 to 2.5 times the working load (WL) Verticality