A slope alongside a home in Montana consisted of a steep and rocky terrain that was prone to erosion. Prior to installing the 4" geocell panels to reinforce the slope, prep-work was done to re-grade, smooth and even out the slope, so that the panels could lay flush against the subgrade.
The slope was about a 2:1 incline and required long-term anchoring to hold the panels in place to keep them from sliding. Tendon strapping along with curved rebar j-hooks were used to anchor the 4" tall geocell panels in place. The panels are easily able to be cut and reattached as needed to best fit the area, but to also maneauver around existing obstacles such as existing trees and shrubs. The panels were then filled with a topsoil mixture prior to hydroseeding over top to yield vegetation.
Key Takeaways When Using Geocell for Slope Applications:
Slope Degree/Angle - Generally, slopes at or under a 3:1 are considered globally stable and do not typically require long-term anchoring (with proper installation and infill). With this slope being at a 2:1, the tendon strapping system was used alongside curved rebar to secure the panels into the subgrade.
Preparation is Key - Geocell reinforces sloped profiles similarly to the analogy of paint on a wall; the "wall" or slope will need to be prepped, solid and sturdy prior to installing the "paint" or geocell. The geocell does not create the foundation of the slope, but rather reinforces it by holding infill (gravel, topsoil, sand, mulch, etc.) in place to reduce further erosion and runoff. The geocell panels will also need to lay flush against the current subgrade to keep material from sliding underneath the panels, which can undermine the system, damaging the slope. This is why preparing the slope is key before installing geocell to reinforce slopes.
Selecting a Cell Height - When selecting a cell height for your slope, consider the type of sub-base the panels will be installed on, the slope degree as well as the type of infill you are using inside the cells. Below is a link to our Slope Suggestion Guide to reference when designing with geocell.
As always, these thoughts are offered with the understanding that they do not constitute an engineering opinion or an engineering design. They are suggestions made by the manufacturer for the customer’s consideration. Any design must be developed by an engineer licensed in the jurisdiction of the project and retained for the purpose of designing the system.