InfraDrainGN-76DS (Geonet): ANSTO PROJECT

Case Studies

// Case Studies • InfraDrainGN-76DS: Geonet

InfraDrainGN-76DS (Geonet): ANSTO PROJECT

The Project

The Little Forest Legacy Site, managed by the Australian Nuclear Science and Technology Organisation (ANSTO), required an advanced capping solution to remediate waste disposal trenches containing buried historical waste. The purpose of the project was to limit rainfall infiltration, minimize radionuclide migration into groundwater, and control overflow during heavy rainfall events. A critical component of the design was the inclusion of a geocomposite drainage layer to ensure proper drainage and maintain the structural integrity of the capping system. For this, InfraDrainGN-76DS, a tri-planar geonet, was selected to provide superior drainage performance and durability.

Challenges

The project posed several challenges due to its environmental sensitivity and demanding performance requirements. The site’s trenches required a drainage layer capable of handling high transmissivity to prevent water pooling and infiltration into waste layers. Additionally, the drainage material needed to exhibit durability over a 10-15 year design life, resisting potential chemical exposure from buried waste and maintaining performance under sustained loads from overlying materials.

Traditional drainage solutions, such as aggregate layers, were considered impractical due to their bulk, cost, and potential for clogging over time. The design team sought a lightweight, cost-effective, and high-performing geosynthetic alternative to address these issues without compromising the site's long-term environmental safety.

// Our Solution

InfraDrainGN-76DS was chosen as the geocomposite drain for the project due to its advanced design and suitability for the demanding site conditions. This product features a tri-planar HDPE geonet core laminated to two layers of separation geotextile, providing high transmissivity and exceptional strength. The following benefits of InfraDrainGN-76DS made it the ideal choice:

High Transmissivity: The tri-planar geonet core ensures efficient water flow, even under heavy loads, meeting the site’s stringent transmissivity requirement of 2.60 x 10⁻³ m²/s (minimum).
Lightweight and Easy Installation: Compared to traditional aggregate drainage, InfraDrainGN-76DS is lightweight, allowing for rapid deployment and reduced transportation costs. This made it possible to install the drainage layer within tight project schedules.
Durability and Resistance: The HDPE material provides excellent resistance to chemical exposure and ensures long-term durability. Its tensile strength of 12 kN/m (minimum) ensures that it can withstand the load of the overlying capping layers without deformation.
Cost-Effective: The geonet significantly reduced the amount of imported fill material required, lowering project costs while ensuring environmental compliance.

InfraDrainGN-76DS was installed beneath the geomembrane capping layer, acting as a critical drainage medium while protecting the liner from hydrostatic pressure. The material was delivered in rolls and deployed efficiently using standard construction equipment, aligning with the project’s timeline and budget.

Results

The implementation of InfraDrainGN-76DS at the ANSTO facility resulted in a robust and reliable drainage system that met all performance and durability requirements. Its high transmissivity and strength ensured effective drainage, reducing water infiltration into the waste trenches and supporting the overall integrity of the capping system. The lightweight, cost-effective solution also minimized construction time and environmental impact.

The success of InfraDrainGN-76DS in this project underscores its effectiveness in challenging environmental applications, making it a preferred choice for large-scale remediation and drainage projects. The geonet's performance has set a benchmark for innovative geosynthetic solutions in environmental engineering.