Slope stability with geocells at a New Zealand playground

Aronia Park is a colorful new playground in South Auckland, New Zealand, that includes two multihued slides. The challenge arose with the specified topsoil thickness for the steep slope beneath the slides. There was a risk of the slope soil sliding off and requiring costly repair.

Greenscene, the contractor, approached Cirtex of Thames, New Zealand, about a solution that would hold 8 inches+ (200 mm+) of topsoil on a 45˚ slope that is 26 feet (8 m) long. Cirtex worked closely with the contractor and provided a project concept to demonstrate a possible solution.

Greenscene chose Cirtex’s 8-inch (200-mm) depth StrataWeb SW445 Geocell and the proprietary StrataCord/StrataFast Anchoring system to contain the topsoil on this angled site.

The contractor first applied a layer of StrataGrid SGU90 Geogrid to the slope to provide additional reinforcement of the StrataWeb. The StrataGrid layer under the StrataWeb allowed the DuraMat pin quantity to be reduced from 4 per m² to 1 per m², saving time and cost on-site.

The geocell was then pulled down the slope with the StrataCord already in-stalled through the cells at 1.6-feet (0.5-m) spacings. The StrataCord was connected to the StrataWeb cells using the StrataFast locking clip. Then, 24-inch (600 mm) long DuraMat pins were installed at 1 per m² spacing before the topsoil was laid into the finished StrataWeb.

StrataWeb provided the following benefits:

• An engineered solution for the containment of topsoil on a steep slope
• Conceptual recommendations on the spacing of the anchoring system
• Support from Cirtex staff before and during installation process