ACEGrid® Reinforced Earth Structure with a Galvanized Welded Wire Mesh Facing at a Downslope of Elementary School

The site of the reported case is a downslope under the playground of elementary school, and it is also in the immediate proximity of an important local service road in northern Taiwan.

The slope collapsed in 2003 after an attack of torrential rain. The slope collapse continued to expand because of enormous rainfall infiltration in the rainy season, which jeopardized the adjacent retaining wall's stability and seriously affected road traffic safety and convenience. The height of the collapsed slope was up to 15m, and the space for rehabilitation was also very limited. Considering the safety of the construction and the local service requirements, the designer vigorously called for a rapid and efficient method for restoration.

After comparing multiple schemes, the final decision was to use a reinforced earth structure with a galvanized welded wire mesh facing. The collapsed slope was restored to a multi-staged reinforced earth retaining wall with an averaged slope of 1:05 (V:H) and a total height of 15m using ACEGrid^® with galvanized welded wire mesh facing. Because of the frequent heavy rainfall at the site, installation of the drainage system was essential. As the reinforced earth structure was constructed layer by layer, the horizontal ACEPipe^TM and the vertical ACEDrain^TM were installed to avoid water staying in the reinforced zone, forming seepage pressure and affecting safety. In addition, a geotextile layer was placed behind the WWM facing to prevent the backfill from being eroded by rainwater or runoff.

1. Structure Safety
No damage has occurred in either case so far. No noticeable deformation appeared on the wall face, the crest, and the corner of the retaining structure. The present structural conditions the cases are sufficient to verify the advantages mentioned above of the ACEGrid^® reinforced earth retaining structures with a welded wire mesh facing.
2. Landscape and Ecology
After hydroseeding, the ACEGrid^® reinforced earth retaining wall with a welded wire mesh facing has matched well with the adjacent natural slope and it was harmonious with the surrounding landscape. Even when the owner carried out weeding and maintenance operations to expose the wall, it showed a better appearance than the gray and monotonous traditional reinforced concrete structure. It also has shown traces of biological activity on the wall, demonstrating the system as an eco-friendly environment.