Project Name: RR30 Wagg Road Slope Protection
Project Location: Uxbridge, Ontario
The “York Durham Line” refers to the boundary line that separates Durham Region from York Region in Ontario, Canada. The York Durham Line/RR30, operated by Durham Region, runs adjacent to Island Lake and is a vital artery for both residential and commercial traffic within the area.
Within this region, an essential single-lane asphalt road had reached the end of its service life and was scheduled for reconstruction. A pavement inspection was completed on this road that identified several concerns, including embankment and slope failure, as well as toe erosion along the embankment bordering Island Lake.
Visible evidence indicated multiple unsuccessful attempts to repair the slopes using a variety of methods including steel mesh and gabion stones. The inspection identified several potential failure mechanisms, including toe erosion due to wave action, inadequate road drainage during high precipitation events, and steep slope geometry of 1.2:1V. These factors have contributed to the failure of embankment and road surface. Addressing these potential failure mechanisms is essential before reconstructing the roadway.
Identifying a Geosynthetic Embankment Stabilization Solution
The project engineer contacted the Layfield Group, a geosynthetic material provider, to explore potential erosion and slope protection solutions for the steep slopes along the small lake’s embankment. The project owner preferred a vegetated solution to preserve the natural habitat over a hard-armor, concrete facing method. The chosen solution would need to stabilize a vegetated veneer, provide slope protection during wave action along the 1.3:1 embankment and accommodate a guide rail system.
Layfield’s engineering team worked closely with the Presto Geosystems engineering team to evaluate solutions that would meet the project requirements. A complimentary project evaluation was completed by the Geosystems team that provided a structurally sound, vegetated solution based on the project parameters.
The GEOWEB® Slope Protection System was selected as the ideal geosynthetic solution.
Installing the GEOWEB Geocell System on a Roadway Embankment
The GEOWEB System was deployed along the slopes to prevent surface and toe erosion. The geocell system’s 3D honeycomb-like structure confines and stabilizes the soils, enabling construction of steeper slopes, promoting root lock up for optimal vegetation growth, and resists sheet flow.
In preparation for the installation of the GEOWEB system, the contractor graded the slope and covered it with a medium-weight, non-woven geotextile fabric. The fabric provides separation between the granular embankment materials and the GEOWEB infill.
The GEOWEB panels were expanded down the slope from crest to toe with adjacent sections connected using the ATRA® Connection Keys. The GEOWEB System was anchored using the patented ATRA Tendon Clips with a series of high-strength tendons, which were then tied off to Duckbill earth anchors installed at the crest.
After the GEOWEB panels were deployed, the contractor infilled the cells using an engineered fill consisting of granular aggregate and topsoil, followed by hydroseeding. To protect the newly placed seed and accelerate vegetation growth, a North American Green C125 100% coconut temporary erosion control blanket was installed.
Project Results
Installation of the GEOWEB Slope Protection System was completed in less than a week. The Durham Region, project owners, and the contractor were very pleased with the outcome of the solution. The contractor was particularly happy with the simplicity of the GEOWEB system and components.
Within two months of installing the GEOWEB Slope Protection System, the vegetation was establishing across the entire slope. The vegetated finish was aesthetically pleasing and blended seamlessly with the natural landscape.
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