Cellular Confinement (Geocell)

The ideal soil for construction projects is easily compactible and free draining. Unfortunately, a free draining soil is often difficult to compact. Non-compacted or weak soils can be displaced by stress forces and are subject to erosion. Cellular confinement (Geocell) is a solution.

How Cellular Confinement (Geocell) Works 

Envirogrid GeoCell is made from high density polyethylene (HDPE) and manufactured in the USA. HDPE has been used for the most demanding industrial products since 1955. By confining the soil particles, cellular confinement allows the use of free draining and poorly compacted soils. The three-dimensional cells impede lateral movement of the infill material, increasing structural strength and locking in materials for erosion protection. The cell walls are perforated to allow water flow through the system, creating an improved root zone between cells for vegetated applications.

Aggregate is another free draining material that may not compact well. It can also be expensive to produce and haul. When used with a nonwoven geotextile separator, cellular confinement can significantly reduce both the amount and the quality of aggregate required to stabilize a poor load bearing soil. 

On concrete filled GeoCell, the HDPE matrix becomes the form for the concrete. There is no need for wood forms or rebar. The panels are expanded and the concrete poured directly into the GeoCell.

A Bit of Cellular Confinement (Geocell) History

It is interesting to note that the first cellular confinement was not necessarily black in color or made of polyethylene. Early attempts included wax-coated craft paper, drainage pipe stapled together, thin and hexagon shaped aluminum glued together, various medium-density recycled materials, polyethylene without UV stabilizers, and square cells constructed in a pattern similar to egg cartons.

In the late 1970's The US Army Corps of Engineers (USACE) began research and development of a stronger confinement system for sand applications that would maintain strength under heavy vehicle loads. They welded strips of plastic into a rectangular, expandable honeycomb structure that when filled with sand supported the heavy loads applied by military vehicles and resisted erosion by wave action.

In 1984, the military demonstrated the effectiveness of cellular confinement in an exercise at Fort Story, Virginia involving thousands of passes by military vehicles over roads constructed of sand and cellular confinement. In 1990, 6,400,000 sf of cellular confinement were successfully utilized during Operation Desert Storm, including the rapid construction of fortified walls.

Base Stabilization

Envirogrid GeoCell is a confinement system that performs better than conventional crushed stone sections, and it provides an expedient construction technique for access roads over soft ground without being adversely affected by wet weather conditions. GeoCell can also be used to strengthen paved areas.

Slope Reinforcement

On slope applications, Envirogrid GeoCell can be filled with angular rock, concrete or with vegetated soil. The cells confine the infill material, creating a stable layer protecting the slope from erosion. GeoCell is a flexible system that will contour to the subgrade of a slope, reducing preparation time. When filled with vegetated soil or rock, the system is permeable - reducing water runoff.

Channel Protection

Envirogrid GeoCell can be installed on slopes as steep as 60 degrees and on channels with flow velocities greater than 25 ft/s (7.6 m/s), depending on infill material. Angular rock is used for velocities up to 10 ft/s (3 m/s), vegetated soil up to 20 ft/s (6 m/s) and concrete for velocities greater than 20 ft/s (6 m/s).

Retaining Walls

A Geocell wall can be an esthetically pleasing, labor efficient, and cost-effective solution. The first flexible cellular confinement wall was constructed in 1988 in Richmond Hill, Ontario. Envirogrid GeoCell can be used for both cut and fill applications on retaining walls. The flexible HDPE panels are custom made to the front to back dimensions required by the project engineer. GeoCell can be easily installed around curves, pipes or other structures. The panels are constructed with the front facing strip colored green or tan to blend in with the surroundings. GeoCell panels can be stacked to create a 90 degree wall, or they can be stair stepped at every layer to create exposed cell for vegetation. Envirogrid GeoCell is the perfect green wall solution. 

The next time you are at the new Washington Nationals Park, check out the batter's eye in center field: Cellular confinement is reinforcing the vegetation in this unique architectural feature!