Brosur Tensar Erosion Control

Contact Tensar International or your local distributor to receive further literature covering Tensar products and applications. Also available on request are product specifications, installation guides and specification notes. The complete range of Tensar literature consists of: • Tensar Geosynthetics in Civil Engineering A guide to the products and their applications • Ground Stabilisation Reinforcing unbound layers in roads and trafficked areas

Chalk highway cutting immediately after Tensar installation

• Tensar Structural Solutions Bridge Abutments - Retaining Walls Steep Slopes • Foundations over Piles Constructing over weak ground without settlement • Basal Reinforcement Constructing embankments over weak ground • Railways Reinforcing ballast and sub-base layers under railway track • Asphalt Pavements Reinforcing asphalt layers in roads and trafficked areas • Erosion Controlling erosion on soil and rock slopes

Your local distributor is:

Chalk highway cutting showing vegetation taking hold.

The grid controls the fall of rock fragments.

Controlling erosion on rock slopes Weathering and freeze-thaw action can often lead to fracturing and spalling on rock slopes, creating the hazard of falling rock fragments and ongoing erosion. These falls are particularly dangerous when close to public areas. TENSAR BIAXIAL GRIDS - THE LONG-TERM SOLUTION

The fixing details including the length and spacing of bolts is site specific and primarily governed by the nature of the rock, slope geometry and the purpose of the protection. Adjacent grid rolls are overlapped and stitched with a high density polyethylene (HDPE) braid to form secure vertical joints. Typical installation details are available on request.

Tensar biaxial grids can be draped over the face and secured with rock anchors to act as a cladding to control loose rock fragments and remove the hazard of bouncing projectiles. This can allow topsoil and scree to be retained and facilitates the subsequent development of vegetation which in turn improves stability of the surface.

Tensar rolls are wide and light, aiding installation.

Tel: +44 (0)1254 262431

New Wellington Street

Fax: +44 (0)1254 266868

Blackburn BB2 4PJ

E-mail: [email protected]

United Kingdom

www.tensar-international.com

Q 05288

EMS 86463

BS EN ISO 9001:2000

BS EN ISO 14001:2004

©Copyright Tensar International Limited Printed April 2006 Issue 7, 79010013 The information in this brochure is supplied by Tensar International free of charge. Tensar International do not assume any duty of care to you or any third party. No liability for negligence (other than for death and personal injury) can arise from any use of or reliance on the information in this brochure or use of any Tensar International product mentioned. Tensar International will not be liable if this brochure contains any misrepresentation or misstatement. Determination of the suitability for any project of the information and any Tensar International product mentioned in it must be made by your engineer or other professional advisor who has full knowledge of the project. You, together with any such engineer or advisor, must assume all risk of loss and damage of any kind arising from use of the information or any product of Tensar International other than the risk of death and personal injury. If you or any third party subsequently purchases a product referred to in this brochure or any other Tensar International product the entire terms of the contract of purchase and the entire obligation of Tensar International relating to the product or arising from its use shall be as set out in Tensar International's Standard Conditions in force at the time of purchase, a copy of which may be requested from Tensar International.

Protecting a railway cutting.

Tensar Biaxial grids - the benefits ■ Cost-effective solution

■ High impact resistance

■ Easy to install, wide, lightweight rolls

■ Non-corrodible, durable

■ High resistance to weathering

■ High resistance to ultra-violet light

■ Aids establishment of vegetation ■ Environmentally safe

Tensar International Limited

Erosion Controlling erosion on soil and rock slopes

Railway application of Tensar Mat

Tensar Mats are used to control erosion on the banks of lakes and reservoirs.

The problem: gully erosion of railway slope.

Tensar Mat installed over the slope.

The solution: Tensar Mat fully vegetated.

Highway application of Tensar Mat Tensar Mat

Pegs

Installing Tensar Mat on the slopes of a stilling pond.

Once vegetation becomes established the use Tensar Mat is inconspicuous.

Tensar Technology - proven practical solutions and the know-how to get them built

For details of Tensar workshops visit www.tensar-international.com

Based on the unique properties of Tensar geogrids, Tensar Technology is widely adopted for ground stabilisation and soil reinforcement problems. Tensar Technology delivers real savings in cost and time to your projects. We can help you apply Tensar Technology to improve the bottom line on your project.

Q 05288

EMS 86463

BS EN ISO 9001:2000

BS EN ISO 14001:2004

Unsurpassed experience and reliability Tensar International is the world leader in erosion and geogrid technology and has over 20 years experience in providing high performance ground stabilisation, erosion and reinforced soil solutions. Tensar offers a broad variety of cost-effective and efficient options for construction projects to combat erosion, which require retaining walls or slopes. Tensar’s experienced civil engineers are available to provide design and on-site construction support for your erosion project - from concept to completion.

The top of the mat is buried in an anchor trench.

Mats are unrolled down the face of the slope.

Controlling erosion on grass slopes

Railways and highways

Natural vegetation can provide good soil erosion protection. However, this may not be adequate on steep slopes (including those strengthened with soil reinforcement, ground anchors or soil nails).

In these cases, an additional permanent erosion protection layer is needed to enhance the resistance of the vegetation - but one which visually becomes part of the slope.

Areas prone to temporary water inundation, wave run-up or intermittent high velocity flows, such as river banks, shorelines, ditches, flood bunds and dam spillways, can also suffer from soil erosion.

■ Rivers ■ Reservoirs ■ Flood bunds

Tensar Mats are manufactured from polyethylene - a polymer that is chemically inert and therefore noncorrodible. Polyethylene is not susceptible to water absorption and deterioration and non-polluting to its installed environment. It is also microbiologically inert and therefore not attacked by bacteria and provides no nutrient for animals.

■ Lakes ■ Drainage ditches ■ Overspill ponds

There are two standard grades of Tensar Mat: Tensar Mat 200 for routine erosion control applications and Tensar Mat 400 for the more critical applications such as very steep slopes/high flow forces.

Tensar Mat - the permanent solution

Tensar Mat - the benefits

By combining our specialist knowledge of erosion, materials, application technologies and geotechnical design techniques, we are able to offer the complete solution for structural integrity and long-term reliability.

■ Cost-effective long-term solution for erosion control Tensar grids and mats are often used as a facing to soil-nailed slopes.

■ Easy, quick and economic to install ■ Natural, attractive appearance

The Tensar Mat range is used to control soil erosion. It consists of a flexible three-dimensional polymer mat which initially stabilises the surface whilst assisting vegetation to establish. It then goes on to provide long-term, tenacious reinforcement of the root system. The mats have a flat, high tensile modulus base layer bonded to an upper cuspated surface which provides an array of pockets and traps for topsoil retention.

The thick, dimensionally-stable matrix of filaments presents an ideal medium for anchorage and reinforcement of a root system. Reinforced grass slopes have been shown to have an erosion resistance able to withstand current velocities in excess of 4m/sec.

■ Environmentally safe

Tensar Mats have unsurpassed drape qualities, which allows them to closely conform to, and maintain intimate contact with, the soil surface. This can be critical to prevent uplift of a mat as well as to control soil erosion below. In addition, roots will not be able to penetrate through to the soil surface if voids exist underneath a mat.

■ Aids establishment of initial vegetation growth

■ May replace some obtrusive and expensive traditional revetments ■ Maintains close contact with the soil profile for maximum root anchorage ■ Avoids topsoil creep on slopes ■ Protects against ‘bald spots’ on grass slopes subject to high wear ■ May be used with hydraseeding and soil nails

Shoulder Trench

Typical section showing Tensar Mat on a highway slope.

Installing Tensar Mat on grass slopes 1 Prepare the slope to be treated by trimming the profile. 2 Place 50-70mm of topsoil on the prepared slope (this is optional depending on the soil type and uniformity of the prepared slope). 3 Unroll the mat down the face of the slope flat side down, lapping adjacent strips by a minimum of 100mm. 4 Fixings (either Tensar Pegs or approved mild steel pins) should be at around 1m centres (depending on the slope angle) along the laps. 5 Bury the top and bottom ends of each strip at the shoulder and the toe, respectively, in shallow trenches typically 450mm wide by 250mm deep. 6 Sow grass seed into the mat. 7 Brush friable soil into the full depth of the mat. 8 Re-sow the slope and apply (optional) fertiliser. 9 Lightly tamp the soil surface. Omit steps 6 to 9 for planted slopes. The soil-filled mats can be slit longitudinally to accommodate planting.