Geotextiles are frequently used for subgrade improvement under roadways. Caltrans has released a document titled "Guide for Designing Subgrade Enhancing Geotextiles". This 18-page document covers what situations can be improved using geotextiles and includes a flowchart for guidance on when to apply them and for what purposes. From Geosynthetics magazine. (Image by Caltrans)
In this ENR.com video, a US Army Corps of Engineers (USACE) project to protect Grand Isle Louisiana from the erosional effects of a large storm surge is described. 5.7 miles of sand filled geotextile tubes or geotubes 30-ft in diameter are used to form the core of a dune along with a geotextile erosion apron held in place by anchor tubes. The design is aimed to prevent devastating erosion in the event that a large storm surge overtops the protective dunes. The sand is screened on site and mixed with water to form a slurry that is pumped into the tube. Once the tubes are in place, additional sand will be placed over the top and the dune revegetated. If the topping sand is eroded away, the Corps hopes the fix will be easier to perform with the tubes. Click through for the video.