Geonets

A geonet is a geosynthetic material similar in structure to a geogrid, consisting of integrally connected parallel sets of ribs overlying similar sets at various angles for in-plane drainage of liquids or gases.

[1][self-published source] Geonets are formed by a continuous extrusion process into a netlike configuration of parallel sets of homogeneously interconnected ribs.

While quite different in the manufacture or configuration than geonets are competitive geosynthetic products called geospacers.

Their drainage cores consists of nubs, columns, cuspations, or 3-D networks of stiff polymer strands.

[1] Since the primary function of a geonet is to convey liquid within the plane of its structure, the in-plane hydraulic flow rate, or transmissivity, is of paramount importance.

A series of environmental related issues can have impact on the flow-rate performance of geonets.

For geonets serving as a drainage medium, the targeted value is flow rate and the above concept becomes:

As seen in the equation, q/W and θ carry the same units and are directly related to one another by means of the hydraulic gradient i.

While UV and heat effects are not as severe in geonets as they are in geotextile (because of thicker ribs in contrast to thin yarns and fibers), it is good practice not to leave the material exposed and subjected to accidental damage or contamination of any variety.

Contamination can occur from soil, miscellaneous sediment, construction debris, ingrowing vegetation, and so on.

If triplanar or boxlike channel geonets are being used for their high flow in the machine direction, the proper orientation is critical during placement.

Assuming stress does not have to be transferred from one roll to the next, plastic electrical ties, threaded loops, and wires have all been used with a relatively small overlaps of 50 100 mm.

Notwithstanding the above concerns, geonets are very impressive with respect to their flow-rate capability, ease of construction, savings in airspace, and overall economy in many facilities where drainage must be accommodated.