Cellular Confinement Systems and its Use in Roadways: How Sustainable is CCS?
Cellular confinement systems, otherwise referred to as geocells, are used in building of soil stabilization on even ground and steep slopes, erosion control, channel fortification, and structural underpinning for weight support and earth retention. Normally, CCS are made using Novel Polymeric Alloy (NPA) and/or ultrasonically welded high-density polyethylene (HDPE) strips and are expanded on-site to create a structure similar to a honeycomb. They are also filled with soil, sand, gravel, rock or concrete.
Cellular Confinement Applications in Roadway Load Support
Cellular Confinement Systems continue to be used in improving the efficiency of both unpaved and paved roads by fundamentally reinforcing the soil within the pedestal course or in the sub standard-base interface. CCS is rather effective in the sense that when effectively distributed, it creates a stiff, strong cellular mattress. The 3 dimensional mattress lessens vertical discrepancy settlement into pliable subgrades, develops shear strength and augments load bearing capacity, at the same time reducing the amount of collective material needed to generally lengthen the service life span of roads. Classic load support functions include underpinning of sub-base and base layers in pliable pavements, including: unpaved access, asphalt pavements, railway substructure, military roads, airport runways as well as aprons, porous pavement, green parking facilities, pipeline road support and crisis access areas.
How Cellular Confinement System Works
A CCS, when installed with pressed soils, consequences to a new complex entity that contains enhanced reflex and geotechnical properties. When the ground contained within a cellular confinement system is subjected to stress, it causes imaginative pressure on edge cell walls. The 3 dimension zone of the confinement lessens the agile movement of the soil elements while perpendicular stress on the enclosed infill yields to elevated agile stress and resistance on the soil interface. As such, CCS increases the strength of the reinforced soil, which then:
- Creates a tough slab or mattress to dispense the load over an extended area
- Lessens punching of the supple soil
- Increases tear resistance and generally bearing capacity
- Reduces deformation
Furthermore, confinement from contiguous cells provides additional immunity against the burdened cell via passive resistance while cross extension of the infill is limited by what is mechanically known as high hoop strength. Finally, compaction is sustained by the confinement, leading to long-term reinforcement.
On site, the CC sections are tied together and placed unswervingly on the subsoil’s surface or/and on the geotextile filters used on the subgrade surface. Depending on the slice and cubicle size, the sections may expand to a stretch of numerous tens of meters and often consist of hundreds of distinct cells. Once laid, the geocells are then packed with a mixture of tough materials such as sand, soil, recycled material or aggregate, and then pressed using vibratory pressing machines. Surface layers may be of unbound gravel materials or asphalt.
How Sustainable is CCS?
CCS is a rather green solution that can now make civil infrastructure projects supplementarily sustainable. The system significantly reduces both the quantity and type of infill required to underpin the soil and the use of earthmoving machine and haul is also reduced. In turn, there is a decline in fuel usage when the system is used, thus reducing the emissions of harmful gases. The system also reduces erosion and as such provides outstanding soil protection, growth stratum and water drainage for plants.
Image source: Presto