Driven Piles with Subsequent Placement of Concrete
(typically end-bearing piles)
Installation of the Driven Ductile Iron Pile is one of the quickest and simplest piling methods available. The pile is driven to a "set" in dense gravel or onto bedrock. Concrete is then placed into the bore of the pile to give additional strength.
An end plug or rock point is fitted to the lead section, which is then driven to its full length, with additional sections added as required.
The set is defined as the reduced rate of pile penetration, in relation to a sustained driving energy (of the hammer), over a given time. Achievement of the set demonstrates the pile’s ability to sustain its design load on a long term basis.
The value for the set (i.e. penetration rate in relation to sustained driving energy) is determined from empirical data, correlated with static load test results, in a range of different ground conditions over many years.
Set Data
| Pile type | Hammer Size | Hammer Power | Penetration Rate |
| [mm] / [in] | Krupp / Atlas Copco | [Joules] / [ft-lbs] | [mm/min] / [in/min] |
| 118 / 4.65 | HM 1000 / MB 1700 | 3577 / 2638 | 30/1 / 1.2/1 |
| 170 / 6.69 | HM 1500 / MB 2200 | 4950 / 3651 | 30/1 / 1.2/1 |
Notes:
- Set should be proven by three re-drives on first five piles, thereafter once or twice, in conjunction with monitoring of adjacent driven pile lengths.
- The more powerful hammers can be used with the smaller piles, but the rate of penetration for the set remains unchanged.
Contact Bearing Area
| Pile type | End Plug | Contact Bearing Area of End Plug | Pile Socket | Extra Bearing Area of Socket |
| [mm] / [in] | [mm] / [in] | [mm2] / [in2] | [mm] / [in] | [mm2] / [in2] |
| 118 / 4.65 | 120 / 4.72 | 11311 / 17.53 | 160 / 6.3 | 8797 / 13.64 |
| 170 / 6.69 | 175 / 6.89 | 24055 / 37.29 | 218 / 8.58 | 13275 / 20.58 |
- Grout Injection through the pile bore during driving
- Cutaway Options for grout injection piles
Driven Piles with Grouted Annulus
(typically skin friction piles)
Grouted driven piles combine the installation benefit of a driven pile with the flexibility of a grouted system.
An oversize grout shoe is fitted to the base of the lead pile section. As the pile is driven into the ground, the oversize shoe creates an annulus between the pile shaft and the ground which is constantly filled with a pile concrete to mobilize skin friction.
Installed by the simultaneous drive and grout technique, grouted piles can be also used in ground conditions where other systems are not suitable (i.e. high ground water or contaminated sites).
Indicative Driving Rates and Skin Friction Values
| Soil Type | SPT | Driving Rate | Skin Friction | |
| [kPa] / [psi] | [N] Value | [Sec/m] / [Sec/ft] | [N/mm2] / [psi] | |
| Cohensive | ||||
| Stiff | 75-150 / 11-22 | 10-14 | 10-15 / 3-5 | 0.04 / 5.8 |
| Very Stiff | 150-300 / 22-44 | 16-30 | 15-30 / 5-9 | 0.07 / 10.15 |
| Hard | >300 / >44 | >30 | >30 / >9 | 0.1 / 14.5 |
| Granular | ||||
| Medium Dense | 10-30 | 10-20 / 3-6 | 0.08 / 11.6 | |
| Dense | 30-50 | 20-30 / 6-9 | 0.12 / 17.4 | |
| Very Dense | >60 | >30 / >9 | 0.15 / 21.75 | |
Notes:
- Driving rates based on grout shoe (200mm dia. for 118mm piles, 250mm dia. for 170mm piles).
- In cohesive soils, driving rates require careful assessment, due to the potential for build up of positive pore water pressures during driving.
- Skin friction value of 0.04 N/mm2 (5.8 psi) is informative only, not used for pile loading.
- Skin friction values are based on approximate stresses with a safety factor of 2 applied. Site trials should be conducted to establish actual values.
Sanded Grout Mix
- Highly pumpable cohesive mix, to pass through 2 in. hoses and a 1-3/8" aperture in the hammer shank.
- Slump: 7 in. to collapse.
- Retarder: 6 hours (open life of mix is essential during pump downtime).