Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

CTRL growth strategy

Novel cellular geosynthetic product aids vegetation of CTRL cuttings.

CONSTRUCTION of the Channel Tunnel Rail Link (CTRL) through Kent requires excavation of several deep cuttings.

Working with the CTRL Contract 330 main contractors Alfred McAlpine/Amec jv, geotechnical product supplier Maccaferri provided the Armater cellular containment system to support soil and vegetation on the sides of soil nailed cuttings.

The section shown is the Temple Wood cutting near the River Medway. Located in poor ground, it has an upper slope gradient of 1:2. 5 through the superficial deposits with a 1:1 gradient over an 8m high lower slope. The lower slope in chalk contains clay infilled solution features. Soil nails ensure overall stability of the clay materials, while Armater secured to the surface helps vegetation establish quickly on the steep slopes.

Lightweight, flexible and easy to install, Armater forms cells into which topsoil is placed. These cells reduce erosion caused by surface run-off and prevent formation of gullies. The porous material enables water to flow slowly through the hexagonal cells, avoiding ponding at the base of the cell.

The Armater was laid after soil nailing and secured to the slope surface using 0. 5m long, 10mm diameter steel pins and buckles at 1m centres. An hydraulic excavator placed topsoil in the cells and the project was finished offby hydroseeding.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.