How does Geocell Technology Help us in Soil Stabilization?

Soil stabilization is any physical, chemical, biological or combined method of changing a natural soil so it meets an engineering purpose, such as carrying a road or holding a slope. Mechanical stabilization with geosynthetics is widely used for roads in developing and developed countries alike, because it improves weak ground without hauling in large volumes of better soil.

Geocell is a three-dimensional honeycomb cellular confinement system used for soil stabilization, erosion control and protection against geohazards such as slope failure. Geocells are made from high-density polyethylene (HDPE) or other polymer strips and are used across civil engineering and infrastructure work.

The interconnected cells are filled with on-site granular material. The cell walls stop that infill from moving sideways, which gives the layer stiffness and strength that loose soil does not have.

A Little More About Geocell

A geocell is a three-dimensional cellular structure filled with soil, gravel, concrete or other material to stabilize slopes, support loads and prevent erosion. Most are made of HDPE strips welded together into panels that are shipped collapsed and stretched open on site. The open panel is flexible enough to follow the terrain.

When a load is applied to the infill inside a cell, as under a road base, the infill tries to spread sideways and pushes against the cell walls. The walls resist that push in hoop tension, and the surrounding cells add passive resistance. Confinement limits the lateral movement of soil particles, and friction at the cell-soil interface carries part of the vertical load, so the layer spreads load over a wider area of the subgrade below.

Geocells are used to control erosion, stabilize soil, protect channels, support loads and retain earth.

The U.S. Army Corps of Engineers developed cellular confinement in the late 1970s and early 1980s to build roads for military vehicles over soft sand. The material later spread to civilian use for slope protection and erosion control. Today geocells are used in road construction, landfills, mining operations and green infrastructure projects.

The Perks of Geocells

Road, bridge approach and pathway projects often sit on soil that is too weak, too erodible or too steep to perform on its own. Replacing that soil is expensive and disturbs more ground. Cellular confinement improves it in place, which can lower cost, raise load-bearing capacity and make slopes and bases more stable.

Additional perks of using geocells include:

1. Protection and stabilization of steep slopes

On slopes, geocells are anchored to the surface and filled with topsoil or aggregate. The cell walls hold the infill in place so rain and runoff cannot strip it away, and vegetation can establish in the topsoil. This controls surface erosion and shallow sliding of the cover soil. Deep-seated slope stability still has to be checked separately, because a surface geocell layer does not reinforce the slope at depth.

Geocells can reduce the amount of imported material needed to protect a slope, and the panels are light enough to place largely by hand, so installation does not need heavy equipment. They are widely used on road embankments and cuttings to stop erosion on steep slopes.

2. Protective linings for channels and hydraulic structures

In drains, channels and other hydraulic structures, geocells filled with aggregate or concrete form a flexible lining. The cells keep the infill from being washed out by flowing water, which reduces erosion of the channel bed and sides and the silt carried downstream. A lining of this kind lasts longer and needs less maintenance than bare earth.

3. Static and dynamic load support on weak subgrade soils

Under roads, yards and platforms, a geocell layer filled with granular material acts as a stiff mattress that spreads static and dynamic loads over a larger area of the weak subgrade. This reduces stress on the subgrade, limits rutting and helps prevent bearing failure. Perforated cell walls let water drain between cells and increase friction with the infill.

4. Multi-layered earth-retaining and water-retaining gravity structures

Geocell layers can be stacked, each set back slightly from the one below, to build gravity retaining walls and water-retaining structures. The filled cells act together as a heavy, flexible mass that resists earth pressure, and the outer cells can be planted to give a green face.

Perforations in the strips let water pass through the wall, so water pressure does not build up behind it.

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