Geosynthetics for Erosion Control and Reinforcement Stan Boyle, Ph.D., P.E. Shannon & Wilson, Inc. What are Geosynthetics? Geosynthetics are (generally) polymeric products used in civil engineering applications. Including: erosion control products, geotextiles, geogrids, geonets, geomembranes, geosynthetic ti clay liners, geocells, geocomposites, and geofoam. What are Geosynthetics? Geosynthetics are (generally) polymeric products used in civil engineering applications. Including: erosion control products, geotextiles, geogrids, geonets, geomembranes, geosynthetic ti clay liners, geocells, geocomposites, and geofoam. 1
Erosion Control Nonwoven Geotextiles Filter Fabrics Separation Fabrics Drainage Root barriers Woven Geotextiles Separation Fabrics Silt Fence Root barriers Reinforcement 2
Geogrids Reinforcement Geocells Erosion control Reinforcement Soil confinement Planting cells Erosion Control Temporary (straw and coir mats) Moderate Term Net and natural fiber Long Term all polymer, 3-D 3
Erosion Control Erosion Control Temporary (straw and coir mats) Moderate Term Net and natural fiber Long Term all polymer, 3-D Erosion Control 4
Erosion Control Erosion Control Temporary straw and coir mats Moderate Term Net and natural fiber Long Term all polymer, 3-D Erosion Control High velocity flow channels, steep slopes, pond spillways 5
Woven Geotextile Silt Fence Root Barrier Woven or Nonwoven Geotextile Horizontal or vertical Water flow through Root Barrier Needlepunched Nonwoven Geotextile 6
Geocell Erosion Control Steep slopes, water quality ponds, paths Geocell Erosion Control Geocell Erosion Control 7
Geocell Erosion Control Reinforced Slopes and Walls Horizontal layers of geosynthetic reinforcement Geotextile or Geogrid Face stabilization crucial Vegetation Erosion control geosynthetics ti Wire-basket vegetation, rock-filled Rockery Vegetated Reinforced Slopes 8
Wrapped Face Vegetated RSS 1.5H to 1.2H:1.0V Vegetated Reinforced Slopes 0.75H:1.0V Stacked, 4-inch thick x 18 inch deep turf Vegetated Reinforced Slopes 9
Vegetated Reinforced Slopes 1.2H:1.0V Vegetated Reinforced Slopes 1.2H:1.0V 3 years later Erosion control mat visible where vegetation not established Reinforced Slopes - Geogrid 1.5H:1.0V Used Erosion control mat 10
Reinforced Slopes Geogrid (10 yrs later) Geogrid visible where concentrated runoff eroded surface Wire-basket Face Reinforced Walls >0.5H:1V Rockery-faced Reinforced Wall ~0.5H 0.75H:1.0V 11
Rockery-faced Reinforced Wall Reinforced Soil Slope Challenges 1.2H:1.0V Heavy runoff before vegetation established. Vegetated RSS Challenges 1.0H:1.0V Did not irrigate and maintain until plants established. Seeds mixed into soil? Sufficient organic material? 12
Vegetated RSS Challenges Vegetated RSS Challenges 1.0H:1.0V Slope too steep should have used a wrapped face or wire basket face. Topsoil spread on steep surface. Vegetated Reinforced Wall Challenges Looks OK from angle. Not full coverage looking straight on. 13
Vegetated Reinforced Wall Challenges 10 years later Did not mix seed into soil. Insufficient organic material. Shaded. North facing. Geocell Reinforced Slopes and Walls Available in Black, Tan, Green Geocell Wall 14
CLEANOUT 18 INCH SD FINISHED GRADE EMBANKMENT FILL SUBGRADE DRAIN EXISTING GRADE ORDINARY HIGH WATER MARK RIPRAP Boyle - Geosynthetics for Erosion Control Reinforced Slopes Geocell Faced B Northwest CROSS SECTION B-B' B Southeast 100 100 80 80 Elevation in Feet 60 40 60 40 Elevation in Feet 20 20 0 0+00 1+00 2+00 3+00 0 Geocell Reinforced and Faced Slope Planting Benches Geocell soil reinforcement Geogrid Reinforced Geocell Slope Planting Pockets 15
Reinforced Slopes - Geocell Geogrid-Reinforced Geocell Slope Grade Place Geocell Geogrid REPEAT Geogrid Reinforced Geocell Faced Slope 16
Geogrid Reinforced Geocell Faced Slope Contour slope face Place around existing features Summary Erosion Control Natural Temporary Permanent 3D Geocell Silt Fence Root Barrier Nonwoven Geotextiles Woven Geotextiles Reinforcement Geotextile Geogrid Geocell Facing Vegetation Vegetated wrapped face Vegetated wire basket Rock-filled Basket Rockery Geocell International Erosion Control Association Geosynthetics 2015 Portland, Oregon The North American Geosynthetics Society Manufacturer, Supplier, Contractor Exhibits Technical sessions, lectures Networking Feb. 15-18, 2015 Portland, Oregon 17
Resources Thanks to: QUESTIONS? Propex ACF West TenCate/Mirafi propexglobal.com acfwest.com tencate.com Stan Boyle, Ph.D., P.E. Shannon & Wilson, Inc. 18