Reinforced Soil Walls and Slope Reinforcement
HALTON HILLS - ONTARIO - Canada
THE TOWN OF HALTON HILLS
TENTH LINE LOT 29/30 ROADWAY AND SLOPE REPAIR
Full road excavation and installation of MacDrain
Green Terramesh® during construction
MacGrid® EG during installation
Green Terramesh® fully vegetated, June 2021
Finished road and upper side slope fully vegetated and protected with MacMat® R
Tenth line is a gravel road at the Town of Halton Hills between 27 Side Road and 32 Side Road. Land use in the area is primarily rural residential / farmland. The topography of the site is undulating, with a moderately steep slope. Based on two geotechnical investigations, it was noted that approximately 110 meters of the adjacent slope was in distress. Historically, guardrails had sunk into the slope, until three rows of guardrails had been installed on the slope. The reason for the slope distress was not clear. One theory was that upper slope collected a large amount of water that was not properly diverted, and that ground water had no other option but to move beneath the road and lower portions of the slope. Each spring the town had to add road gravel to continually resurface and regrade the road which necessitated the need for future remedial works.
The town approached Maccaferri in 2016 to seek an engineered solution to this challenge. The engineering team proposed the following four solutions: – Full road reconstruction reinforcing the road subbase with MacGrid® EG. This is a high modulus high density polyethylene (HDPE) grid characterized by a tensile resistance in both longitudinal and transverse directions. – Installation of a layer of MacDrain below the road subbase and behind the reinforced slope. This allows water moving from the upper slope to be diverted beneath the road and directed away from the lower slope. MacDrain geocomposites are made from a plastic drainage core that is thermally bonded to a geotextile on both sides. – Full slope reconstruction with a Maccaferri Green Terramesh®. This is an environmentally friendly modular system used to form a vegetated (green) faced reinforced soil slope. – Upper side slope protection with the use of MacMat® R. To collect water from the upper slope, the slope needed to be regraded, and the slope protected from erosion. The MacMat® R provided an ideal robust solution as it is a reinforced polymer geomat which has a three-dimensional matrix extruded onto a double twist steel mesh. The steel mesh allows it to be installed as one continuous sheet of erosion protection.