GEOTEXTILE PRODUCTS

GEOfabrics geotextiles are highly durable and are characterised by:

• High puncture resistance
• Large elongation before break
• Excellent filter characteristics at all strains
• Specially chosen fibres for high UV protection

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1. Coastal, River and Flood Protection Works

• High extensibility and extremely robust to resist installation and in-service conditions
• Wide widths for minimum overlap (6m wide - 5.9m for export) saving on overlap wastage
• Very high permeability at all strains with negligible uplift in wave conditions
• Very good sand tightness at all strains retaining subsoil without washout

A GEOfabrics' filter/separator provides high extension together with excellent puncture resistance which means little damage occurs when placing large rock. Sustained flow capacity and sand tightness are achieved at all strains.

In very exposed areas where it is possible that accretion of sands may not occur, a secondary mineral filter layer is placed prior to the primary rock armour.

Design charts are available that point to the most appropriate GEOfabrics' product once the size of rock has been established.

The savings in transport, plant and materials is considerable compared with the alternative of having to design/install multiple, graded, mineral filter layers..

Beneath concrete revetment blocks

Revetment blocks need to be placed on a flat, well-prepared surface for them to interlock correctly. This means the underlying material will be of relatively low permeability. It is essential, therefore, to have an high-flow, low-sand-tight geotextile to prevent washout. GEOfabrics filters have flow characteristics which can only be matched by expensive monofilament woven geotextiles.

2. Landfill and Cotaminated Land

GEOfabrics' products have been designed and adapted especially for landfill applications. They are characterised by:

• High puncture resistance at minimum cost.
• Wide widths for minimum overlap (6m wide, 5.9m for export) saving on overlap wastage.
• Cylinder test information for every basal liner application.

Basal and side-wall

Each grade of geotextile has been optimised to provide a particular level of puncture resistance (between 5kN to 40kN) - not weight. Weight is a convenient way of describing geotextile separators but it does not accurately reflect the puncture resistance of a geotextile protector.

In addition, longitudinal band drains are frequently incorporated within the geotextiles, at 0.5m or 1.0m centres, to provide an additional leachate drainage function

Capping

Geotextiles from the lower-strength end of the range are used to protect liners from puncture by cover soils or stone drainage blankets.

High friction resistance, a characteristic of needlepunched geotextiles, is of particular benefit when used with roughened membranes on slopes.

Incorporating longitudinal band drains within the (underside) geotextile protector provides a positive drainage path to collect/convey gas and prevent uplift and loss of interface friction.

In a similar way, band drains incorporated within the (topside) geotextile protector is used to control run off and stabilise the cover soil (above the liner).

3. Railways

GEOfabrics' geotextiles are proven as a filter/separator beneath ballast

• Approved by Railtrack for beneath ballast to reduce pumping
• High damage resistance means sustained performance - no tearing or puncture
• High water permeability allowing water flow in both directions
• Filtration characteristics prevent sub-grade particles migrating to contaminate the ballast
• Minimum wastage as roll can be trimmed to desired width
• Widely used throughout the UK

4. Structural Waterproofing Protection

Geotextile protection for linings

• basements
• bridge abutments and decks
• canals
• roof gardens
• service reservoirs
• tunnels
• retaining walls

Coatings and membranes applied to concrete structures are often in need of protection. Angular materials in contact with the proofing, whether by design or by accident, are capable of penetrating the barrier, particularly if the structure is to be subjected to high confining pressures.

Thick, non-woven geotextiles are the easily-applied and proven solution.

• Protection during installation and in service life
• Optimum puncture resistance at minimum cost
• Narrow widths available for ease of handling (typically 2m wide)
• In-plane drainage options

Whether it’s a polymeric or a bituminous membrane, applied vertically or horizontally, above ground or below, protection to prevent puncture will be required on one or both sides. One of the GEOfabrics’ range of thick, geotextiles will provide the necessary level of protection.

Railway viaduct	Canal/marina

Combining membrane protection with drainage

The Protexia products combine the inherent protection capability of the geotextiles with the additional benefit of in-plane drainage. If the objective is to install a protection layer and prevent the build up of pore water or gas then installing one product, instead of two, will save time and money.

The drainage capacity is achieved by incorporating band drains within the geotextile, or by creating a composite with nets or cuspates (eggbox-like sheets) as the drainage component. So, depending on the anticipated pore water/gas levels and the confining load, the most suitable solution can be chosen.

Service reservoir roof

5. Water and Sludge Containment

Geomembrane protection in the construction of:

• canals
• lakes
• mining lagoons
• ponds
• reed beds
• reservoirs

Polymeric liners are prone to puncture by inclusions within the underlying soil. Equally, if the liner is to be ballasted by stone on top then there is a further potential for damage. Thick, non-woven geotextiles are the proven solution for dealing with this problem.

• Protection to liners (either or both sides) during installation and in service life
• High puncture resistance at minimum cost
• Narrow widths available for ease of handling (typically 2m wide)

GEOfabrics' geotextiles have been widely used in the maintenance and refurbishment of navigations and waterways owned and managed by British Waterways and the Environment Agency.

Protection beneath a liner
Geotextile selection is dependent on the depth of water, type of liner and subgrade quality/condition. GEOfabrics can help identify the optimum protection geotextile to prevent liner puncture from underlying stone.

Protection above a liner Often the upper slopes are exposed to damage and it is good practice to cover these areas with a depth of soil which will sustain vegetation. Alternatively, a stone or concrete revetment can be used to achieve a hard landscaped appearance. The geotextile will protect the liner from puncture from this cover whilst also providing a degree of slope stability.

Ornamental lakes, balancing ponds and reservoirs may also require protection above the liner if they are to be ballasted.	Protection detail around the inlet of a tailing lagoon lined with a geomembrane.

Source: geofabrics.com