Hydraulic Laterally Extruded Pile: A Method to Enhance Bearing Capacity of Pile-Paper

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The study proposes a hydraulically extruded pile (HEP) to increase pile bearing capacity without requiring a larger or longer pile. The HEP is driven into the ground like a plain pile; once it reaches the required depth, hydraulic pressure pushes shaft-mounted extrusions into the surrounding soil. These extrusions are intended to provide additional resistance and displace, thereby densifying, the sand.<br /><br />Small-scale compression tests compared PVC plain and HEP models in poorly graded sand at relative densities of 30%, 45%, and 60%. Both piles were 120 mm in diameter and embedded 270 mm. The HEP had four extrusions arranged in two layers. Capacity was compared at 6 mm settlement, equivalent to 5% of the pile diameter.<br /><br />At that settlement, the HEP carried 506, 606.5, and 798 kg at the three relative densities, compared with 446.5, 490, and 581.4 kg for the plain pile. This represents capacity increases of 13.33%, 23.78%, and 37.25%, respectively. The results indicate that the benefit of the extrusions grows as sand density increases. In tests at 45% and 60% relative density, the extrusions appeared to become active after a critical settlement, after which they reduced further settlement; this effect was not observed at 30%.<br /><br />The findings suggest that shaft extrusions can improve pile capacity, but they are based on limited model tests using PVC piles and plastic extrusions. Further testing is needed with different pile and extrusion materials, shapes, and spacings before applying the results to full-scale foundations.

Keywords

hydraulically extruded pile

HEP

pile bearing capacity

shaft extrusions

compression tests

poorly graded sand

relative density

soil densification

model pile tests

foundation engineering