Spec InterpretationInstallation Guideline: EnviroGrid® Cellular Confinement Slope Stabilization
- Prepare the site by removing all vegetative cover, debris and any unacceptable soils from the area where the EnviroGrid® cellular confinement is to be placed. In accordance with the job specifications, replace any removed soils with acceptable materials and complete all earthwork, including anchor trenches when required. If a geotextile is required, installation should be done in accordance with the job specifications or the manufacturer's recommendations. If tendons are required and the EnviroGrid® does not already have the holes for them, drill the holes before expanding the EnviroGrid® sections. Pre-cut the tendons to the desired length. Remember to allow for the additional length required to tie the tendons to the J-Hooks (rebar bent like a candy cane) as well as the material for the anchor trench.
- Stage the material around the perimeter. Determine where the first section of the EnviroGird® cellular confinement is to be placed and position the collapsed panel at the top of the slope. Tie the tendons to a supporting structure beyond the crest of the slope. This supporting structure may be a length of polyethylene or PVC pipe, a concrete beam or set of concrete blocks placed in the anchor trench. Thread the tendons through the predrilled tendon holes in the collapsed cellular confinement panel. Pull the tendon towards the bottom of the slope and anchor it with a J-Hook. Once all of the tendons are in place and secured at the bottom of the slope the panel is ready to be expanded. The EnviroGrid® cellular confinement panels should be placed into the anchor trench to prevent surface water from undermining the EnviroGrid®. The leading edge of the panel (a minimum of 3 cells) should be placed inside the anchor trench and secured in place with J-Hooks.
- Before expanding the cellular confinement panel, measure down the slope to the designed expanded panel length and width and place J-Hooks at the four corners. A string or chalk line can be used to align the staking locations and borders.
- EnviroGrid® cellular confinement sections should be stretched past the designed length and then allowed to settle back to the desired length. Place the end of the cells over the previously installed J-Hooks and complete the installation of the J-Hooks by making them flush with the top of the cell walls. The tendons must be tied, in tension, down the slope every 4 cells to the J-Hooks or a restraining pin to help transfer the load among various points.
- Adjoining EnviroGrid® sections must be level and flush with each other. Overlap the sides of the EnviroGrid® sections and butt the ends together. Secure the adjoining EnviroGrid® sections with a pneumatic stapler or similar method as required by the job application.
- When the EnviroGrid® cellular confinement has been properly laid in place, the system should be infilled using the materials specified in the job specifications. To prevent possible damage to the system, limit the drop height of the infill to no more than 3 ft. Infill should be placed in the EnviroGrid® from the top of the slope to the base using a front-end loader, backhoe, bucket excavator or conveyor. When using sand, granular or topsoil fills, overfill the EnviroGrid® sections by 1 to 2 inches to allow for settling and compaction. Sand and granular fills should then be blade compacted to the top of the cells. Topsoil fill should be compacted with a loader or backhoe bucket with a tamper plate. Concrete fill should be manually raked and machine finished.