RD Pile Wall - A Water Tight Retaining Wall Structure-Paper

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Pdf Summary

RD pile wall is a retaining-wall system made from drilled steel pipe piles connected by specially designed interlocking profiles. Using down-the-hole percussion drilling, the piles can pass through difficult ground—including dense fill, stones, boulders and existing obstacles—and extend into bedrock in a single operation. This makes the system useful where conventional sheet-pile or secant-pile walls are difficult or impractical to install, particularly in constrained urban sites.<br /><br />The RM/RF interlocks are designed to provide strength and watertightness. Tests found that bitumen-based sealant performed best, with approximately 10 mm of sealant recommended for reliable sealing. The interlock’s injection channel can also be used to improve watertightness and strengthen the pile-to-bedrock connection through grouting. Laboratory testing, field trials and project experience have informed design guidance for interlock resistance, corrosion effects and pile-toe stiffness.<br /><br />The largest project described is the Pasila Tripla development in Helsinki. Its permanent wall comprised 820 piles, reached excavation depths of 21 m, and retained groundwater pressure of about 17 m. Interlocks were filled with bitumen sealant; additional measures were used to meet stringent long-term watertightness requirements. While RD pile walls cost more to install than ordinary sheet-pile walls, drilling rates are relatively consistent across ground conditions and can be substantially faster than secant-pile construction. The system’s principal advantages are reliable installation in challenging soils, bedrock anchorage and suitability for demanding excavations.

Keywords

RD pile wall

retaining wall

drilled steel pipe piles

interlocking profiles

down-the-hole percussion drilling

watertightness

bitumen sealant

bedrock anchorage

urban excavation

secant-pile walls