PAILE saves money, time & CO2 emission by reducing material usage and equipment requirements on average by half. Combining the best features of conventional helical piles with cast-in-place piles, PAILE technology offers: Greater speed of installation, Minimal ground disturbance and heave, No spoil production, Simplified logistics, Minimal lead times, Easy on-site material management, and Requires only small piling equipment

PAILEs unlock opportunity for major cost & risk reduction resulting from on site, full static test measurements and comprehensive, site risk profile which drives further design optimisations (in development). In short - Less conservatism enabled by throughout static tests and real-time subsurface risk modelling

The PAILE requires any machinery equipped with a standard rotary head (piling rig or an excavator). The PAILE auger is a combination of two helices which are separated when the designed depth is reached. Once the helices separate from each other, the material is pumped into the created void (PAILE base). The concrete is also pumped when the drill is recovered from the ground.

As PAILE uses a small displacement screw-in technique, less energy is required during installation: The helices convert torque into thrust and pull the auger into the ground, The small shaft diameter requires less energy to displace soil, Greater strengths – even for weaker soils – can be achieved by forming the enlarged base.

The amount of concrete required to construct a PAILE of a similar capacity to a conventional straight shaft concrete pile is always going to be smaller. This is because the enlarged base mobilises much greater geotechnical capacity and the instant pile capacity verification during formation of the base enables reduction of pile depth.

As with any technology, PAILEs have some limitations in certain ground conditions. In unfavourable ground conditions, the cost can be comparable with other products – but we still provide you with on-site verification testing to reduce your site risks and enable further design optimisation.

PAILEs work in any soil profile suitable for conventional helical pile or displacement pile installation: Clays and silts, Very loose to dense sands and gravels, Residual soils, and Extremely weathered rock

PAILE may not be installed into rock. It may bear on rock, but due to the fact that it is a displacement technique, the auger will not be able to penetrate the rock.

As reported by Perko (2009), it is not uncommon to install conventional helical piles into extremely weathered rock or dense sands with SPT N in excess of 50. As the PAILE method utilises similar drilling technology, PAILEs could also be installed into dense to very dense sands, hard clays or even extremely weathered rocks, but might potentially require predrilling. In addition, if PAILEs are to be installed into such high strength geomaterial, the ratio of helix diameter to shaft diameter would have to be reduced to ensure that there is no structural damage to helices during base formation.

Unlike other installation systems which remove soil from the ground, PAILE displaces the soil laterally during the screwing-in process. This means soil is not removed and brought to the surface.

Yes, there is a limitation on the capacity that can be achieved with PAILE technology. This limitation is driven by the maximum torque and power of existing piling machines. It is to be noted however, that a conventional piling rig equipped with a PAILE auger would be capable of installing piles with up to 8 times higher capacity than if it was installing conventional drilled displacement piles.

Yes, there is currently a limitation on the installation depth. This limitation is driven by the available stroke under the mast of a piling rig. However, it is to be noted that, due to the enlarged base, PAILEs could be founded at relatively shallower depths than conventional piles. A splicing system will be developed in the future to enable installation to greater depths.

The angle of stress dissipation cone in concrete is typically between 45 to 60 degrees. However, a safe value to assume would be 30 degrees. Therefore, the height of the base would be recommended to be equal to H = D – d, where D is the helix diameter and d is the shaft diameter.

If PAILEs are embedded sufficiently deep into the founding layer, i.e. approximately 5 times the base diameter, and during the base formation the lower helix is confirmed to be pushed in rather than the upper helix pulled out, then the pull-out capacity would not be compromised. If, however sufficient embedment has not been achieved and consequently the upper helix has been pulled out during the base forming stage, then the pull-out capacity could be affected. In any case, the lower bound of the pull-out capacity would be immediately known during the installation, as it would be equal to the value of the force recorded at the end of the base forming stage. This would enable immediate reassessment and installation of additional piles, if required, or use of predrilling to achieve greater embedment into the founding layer.

A set of strain gauges is used to provide real time monitoring of stresses within the auger components. This creates an instant calculation of axial force required to separate the helices and make a void. Alternatively, the installation torque measurement from the piling rig can be used to calculate the thrust using conventional theory of power screw mechanisms.

The base is formed by displacing the soil vertically by means of a vertical thrust. This thrust, being a quasi-static force, is therefore equal to the ultimate pile base capacity (or its lower bound).

The unloading of the base has no effect on the measured load required during base formation. Therefore, unloading is irrelevant to the bearing capacity verified during the formation of the base. After the formation of the helix, the soil is indeed depressurized to the pressure of the concrete pumped into the hole. However, the concrete pressure will still be higher than the initial soil vertical effective stress and therefore there is minimal risk of loosening the soil. On the contrary, the preloading of the soil during base formation will increase its stiffness. This may be compared to a typical plate load test performed on a virgin soil. After loading and unloading the soil for the first time, the rebound is typically 2 to 4 times less than the initial settlement. On reloading of the soil, the settlement is typically equal to the rebound, i.e. the reload/settlement curve is stiffer than during the initial loading cycle.

Similar to conventional helical piles, there is a certain risk of the auger not being able to penetrate at pitch, which is typically referred to as “augering”. Augering can adversely affect tensile capacity but does not necessarily affect bearing capacity (Perko 2009). The risk of augering exists in soils where there is a rapid change of strength over a short depth. E.g. soft clay underlain by hard clay or dense sand, with no transitional layer. In such instances, the soil resistance above the helix may at times not be sufficient to provide enough reaction thrust for the auger tip to penetrate into a hard layer. With PAILE technology, this risk is however minimized by: (1) The use of a tapered helix. The bottom helix is specially designed to improve penetration into difficult soils. (2) The use of additional helices along the shaft and of greater diameter than the bottom helix, to increase the reaction thrust available to screw the auger into the ground. (3) The use of sacrificial cutting tips installed at the bottom of the auger in lieu of conventional plastic caps. (4) As a last resort, loosening the soil by predrilling with an auger diameter less than the intended PAILE shaft diameter.

Unlike Franki piles, the PAILE method: (1) Does not use vibration to penetrate into the ground but a screw in process, similar to conventional helical piles. Also the base expansion is by jacking, not by hammering, therefore it does not induce ground vibrations and can be used in the vicinity of existing structures. (2) The enlarged base can be formed not only in sands, but in clays as well. (3) Forms enlarged bases of known diameter, as it is equal to the diameter of the helix used. (4) Provides information on the quasi static load required to displace the soil under the base, which provides an instant verification of the base resistance. Should the base resistance be insufficient at a certain depth, the auger may revert to the drilling phase and penetrate deeper until sufficient base resistance is confirmed. (5) Requires a comparatively smaller piling rig with only a rotary head to install a pile of the same capacity as a Franki Pile. Therefore mobilisation costs and working platform requirements are minimized. (6) Enables much higher productivities to be achieved due to it being a single continuous process. <br />

Unlike Atlas piles, the PAILE method: (1) Creates piles with an enlarged base, not a straight shafted pile with threads. (2) Has helix to shaft diameter ratios of the order of 1.5 to 3, while the Atlas pile auger has a ratio of approximately only 1.2. Therefore the PAILE provides much greater reaction resistance above the helices and also can be installed without requiring high pull-down forces from the piling rig. (3) Does not rely on the formation of threads along the shaft to ensure the pile design resistance. Therefore, the risks associated with augering are irrelevant for bearing resistance. (4) Has higher capacity to pile volume ratio, and therefore is more economical and environmentally friendly

The AI algorithm (technically speaking the Machine Learning algorithms) are under development and are a few years away from reaching a proven, mature stage. The site risk profile is already created, however we still require more data to consider it as a reliable investment decision driver.

The method was already demonstrated on projects in 2022. PAILE continues to build its track record and we estimate it will become an industry standard by 2024.