Cellular confinement systems are commonly used in civil engineering applications for land reinforcement, erosion control, embankment stabilisation, retaining structures and channel protection. Cellular systems such as those available from the UK company Terram Limited are made from various grades of thermally bonded nonwoven geotextile material. Such geotextile materials have the flexibility of a fabric combined with a high tensile strength and relatively high stiffness. They are water permeable so soils are prevented from intermixing while still permitting water to flow freely through the system.
Geotextile cellular systems can be used to confine all kinds of aggregates, soils, sand, etc. of any particle size. They are commonly used in a single layer to help prevent erosion by confining soil on slopes. For example, the ‘Erocell’ system from Terram Limited can be used in the prevention of topsoil erosion on slopes. Cellular systems prevent horizontal movement of the confined material, substantially improving the material shear strength and bearing capacity. They can be used to form access roads, hard standings, embankment slopes, containment dykes and levees, landfill lining and covers, dam faces and spillways, noise abatement walls and parking areas. Alternatively, such cellular structures can be stacked in order to support slopes, construct walls, or form other defensive and protective structures.
Such geotextile cellular systems are typically collapsible, which allows them to be transported flat, deployed on-site and filled on demand. However, the time and energy (manpower, machinery, etc.) required to fill the cellular structure is desirably offset against the convenience of flat-pack delivery. Such systems may not always be suited to situations where it is desired to form a solid structure such as a wall or barrier relatively quickly.
Furthermore, the structural properties of a structure resulting from the filling of a cellular system will depend on the fill materials used, which are usually limited to locally available fill materials, and on the filling method. Whereas larger aggregate materials may allow for faster filling, such fill materials may not always be suitable where the cellular structure is required to act as a more robust impact barrier or in some ballistics defence applications, for example. A problem with finer particulate fill materials such as soil or sand is that they have free-flowing or liquid characteristics, making them potentially more difficult to handle and constrain in some situations.