Execution of bored piles under polymer support – Sustainable and Flexible Concept for a Mega Project-Paper

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The paper examines polymer-based support fluids for deep bored piles, using the NEOM THE LINE project in Saudi Arabia as a case study. Unlike bentonite suspensions, polymer solutions generally have high viscosity but little yield strength. They support boreholes through controlled fluid penetration and, where fines accumulate, formation of a thin filter cake or colmated zone. Long-chain synthetic polymers can also inhibit sensitive clay layers.<br /><br />At THE LINE, BAUER installed 1,365 piles, up to 74 m deep and 2.5 m in diameter, in predominantly sandy soils interspersed with clay and silt. A long-chain acrylamide-acrylate copolymer was selected to stabilize the ground, limit fluid penetration, and allow excavated particles to settle quickly. Project controls included treating variable-quality mixing water, monitoring fluid density, Marsh viscosity, sand content and pH, and using low-shear pumps to avoid damaging the polymer chains.<br /><br />The authors report practical and economic benefits: low polymer consumption, straightforward mixing, rapid readiness for use, faster settling and borehole cleaning, and reduced need for fluid-treatment equipment. These features can improve construction efficiency and reduce handling and disposal costs compared with bentonite.<br /><br />Environmental effects are described as limited and manageable because polymer concentrations are low, penetration is restricted, and suspended solids can be separated. At the project, used fluid was treated with hydrogen peroxide; settled residue went to inert landfill. The paper nevertheless emphasizes that environmental approval and disposal requirements vary by jurisdiction. Early regulatory engagement is essential to select suitable products, plan equipment and waste management, and establish reliable costs and schedules.

Keywords

polymer-based support fluids

deep bored piles

bentonite suspension

NEOM THE LINE

Saudi Arabia

acrylamide-acrylate copolymer

borehole stabilization

filter cake formation

environmental disposal

construction efficiency