The Challenge
Prolonged heavy rainfall caused the boundary retaining wall at a residence in Cheng Soon Garden to collapse. Water accumulation within the slope was a key concern.
The client engaged Hocklim to design a GeoBarrier retaining structure that would improve slope drainage and introduce planting along the property boundary.
The Solution
The system has three key components. First, GeoBags made from high-strength, permeable monofilament polypropylene fabric hold the soil and support planting.
Second, geogrid reinforcement is sewn to the bottom of each GeoBag and extends into the slope. Interaction between the soil and geogrid provides reinforcement and improves structural stability.
The third component is the aggregate material, arranged in three layers: planted approved soil mix (ASM), fine-grained material and coarse-grained material. ASM and fine material fill the GeoBags; coarse material sits behind the fine-grained layer. The different hydraulic properties help divert infiltrating rainwater. Aggregate options include sand and gravel or recycled concrete aggregate (RCA).
Two layers of GeoBags were arranged in an interlocking pattern. Selected plants were added to the planting pockets. The installed system combines drainage and soil reinforcement with a planted boundary that fits the residential setting.