Like HowStuffWorks on Facebook!

How EnviroGrid Works

EnviroGrid Basics
The honeycomb chambers of EnviroGrid are filled with sand.
The honeycomb chambers of EnviroGrid are filled with sand.
Image courtesy of EPA

The concept behind cellular confinement is pretty straightforward: A walled cell will hold anything you put inside it. For instance, if you put sugar inside a cookie cutter, you can move the cookie cutter around without losing the sugar. By extension, a multitude of interconnected cookie cutters will hold a whole kitchen full of sugar, and it'll be even more stable because that huge structure will be much harder to destabilize. Switch out sugar with dirt, and you've got the basic idea behind EnviroGrid.

Of course it's a bit more complicated when you move past baking and into engineering applications. Geocells become, in a way, connected to the ground.

EnviroGrid is a flexible honeycomb structure. The honeycomb cells are open at the top and bottom. The sheet of cells is laid on and secured to any unstable surface, be it level or sloped. It can be used on sand, dirt, rocks, clay -- pretty much anything that might blow or wash away or give out under heavy loads.

The cells are then filled with some sort of aggregate, such as dirt, soil, pebbles or even concrete. It all depends on the application (which we'll get into on the next page). Since the cells are open on both sides, the unstable ground beneath the structure becomes mingled with the added aggregate, and the honeycombs become part of the ground surface. The walls of the cells protect the aggregate from the elements, so instead of wind or water blowing away the dirt, they pass over the tops of the cells. And the added strength of all of those interconnected cell walls multiplies the force the ground can withstand, because any force is spread out over a much larger surface area. The dirt can't be dispersed by the weight, because it can only move around within the confines of the cell.

There are a few particular advantages to using geocells instead of more traditional methods, including appearance, cost and environmental friendliness. You'll see why in the next sections, when we get into applications.