RR30 Wagg Road Slope Protection
SCOPE OF WORK: Supply of Presto GEOWEB® Engineered Slope Protection System
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York Durham Line/RR30, operated by Durham Region, runs adjacent to Island Lake and is a vital artery for residential and commercial traffic. The single-lane asphalt road had reached the end of service life and was scheduled for reconstruction. A pavement investigation was completed, and the report identified several concerns, which included embankment and slope failure with toe erosion along the embankment bordering Island Lake.
There was evidence of several unsuccessful attempts to repair the slopes using various methods, including steel mesh and gabion stones. The evaluation identified several potential failure mechanisms, which included toe erosion due to wave action, inadequate road drainage during high precipitation events, and steep slope geometry of 1.2:1V, which contributed to the failure of embankment and road surface. These potential failure mechanisms would need to be addressed before reconstructing the roadway.
The project engineer contacted Layfield to discuss potential erosion and slope protection solutions on steep slopes, which may be used to protect the embankment along the lake. The owner preferred a vegetated solution to preserve the natural habitat rather than a hard armor or concrete-facing system. The solution needs a stabilized vegetated veneer that provides slope protection during wave action along the 1.3:1 embankment and accommodates a guide rail system.
Layfield completed a project evaluation and conceptual design using Presto GEOWEB® tendon-reinforced cellular confinement system. The GEOWEB® stabilizes the upper soil layer along the embankment to resist sliding and prevent surface and toe erosion. The system allows the designer to construct steeper slopes, resist sheet flow, and promote root lock-up for a stabilized vegetated surface. The GEOWEB® tendon reinforced system is anchored with high-strength tendons tied off to Duckbill earth anchors installed at the crest.
In preparation for the installation of the GEOWEB® system, the contractor graded the slope and covered it with LP8 medium-weight non-woven geotextile fabric to separate the granular embankment materials and the GEOWEB® infill. Duckbill DB68 earth anchors were driven at the crest and spaced every .65m.
The Presto GEOWEB® was then deployed from crest to toe and connected to adjacent panels using Presto Atra Keys. High-strength TP93 Tendons were threaded through the GEOWEB® every 2nd cell from crest to toe and secured to the GEOWEB® cell wall using ATRA Tendon Clips. The GEOWEB® cells were infilled using an engineered infill consisting of granular & topsoil followed by hydroseed and a North American Green C125 100% Coconut erosion control blanket.