Cellular confinement
Cellular confinement systems (CCS)—also known as geocells—are widely used in construction for erosion control, soil stabilization on flat ground and steep slopes, channel protection, and structural reinforcement for load support and earth retention.
[1] Typical cellular confinement systems are geosynthetics made with ultrasonically welded high-density polyethylene (HDPE) strips or novel polymeric alloy (NPA)—and expanded on-site to form a honeycomb-like structure—and filled with sand, soil, rock, gravel or concrete.
[2][3] Research and development of cellular confinement systems (CCS) began with the U.S. Army Corps of Engineers in 1975 to devise a method for building tactical roads over soft ground.
[4] Engineers found that sand-confinement systems performed better than conventional crushed stone sections and they could provide an expedient construction technique for access roads over soft ground, without being adversely affected by wet weather conditions.
[7] This cellular confinement system was made from high density polyethylene (HDPE), relatively strong, lightweight[8] and suitable for geosynthetic extruding manufacturing.
The cellular confinement system was used for load support, slope erosion control and channel lining and earth retention applications in the United States and Canada in the early 1980s.
However, Richardson (2004) (who was onsite at the US Corps of Engineers CCS Vicksburg facility) laments 25 years later on the "near absence of research papers on geocells in all of the geosynthetic national and international conferences.
[19][18] Han (2013) summarizes comprehensive research conducted at the University of Kansas, including static and cyclic plate loading tests, full-scale moving wheel tests, and numerical modeling on geocell-reinforced base courses with different infill materials and discusses the main research findings from these studies regarding permanent, elastic, and creep deformations, stiffness, bearing capacity, and stress distribution, and the development of design methods for geocell-reinforced bases.
[23] Geocells are recognized as a suitable geosynthetic reinforcement of granular soils to support static and moving wheel loads on roadways, railways and similar applications.
These are intended to disseminate the most updated knowledge about the best design methods and practices for implementing geocell technology in soil stabilization and road base reinforcement applications.
A Cellular Confinement System when infilled with compacted soil creates a new composite entity that possesses enhanced mechanical and geotechnical properties.
Cellular Confinement Systems (CCS) have been used to improve the performance of both paved and unpaved roads by reinforcing the soil in the subgrade-base interface or within the base course.
The three-dimensional lateral confinement of CCS along with anchoring techniques ensures the long-term stability of slopes using vegetated topsoil, aggregate or concrete surfacing (if exposed to severe mechanical and hydraulic pressures).
The enhanced drainage, frictional forces and cell-soil-plant interaction of CCS prevents downslope movement and limits the impact of raindrops, channelling and hydraulic shear stresses.
Construction of CCS earth retention is simplified as each layer is structurally sound thereby providing access for equipment and workers, while eliminating the need for concrete formwork and curing.
When used for slope applications, perforated CCS provides excellent soil protection, water drainage and growth stratum for plants for the restoration of green and vegetated landscapes.
