Brosur Tensar Slopes Repair And Reinforcement

Steep Slopes Constructing embankments with steep slopes

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Tensar. The value engineered solution In Tensar you’ll find a partner with the experience and flexibility to respond to your project requirements. From design to completion, we’ll make sure you always benefit from a practical, cost-effective solution to your specific need.

Constructing embankments with steep slopes

A fully indemnified Design and Supply service with full working drawings.

Reinforced soil slopes offer a fast, economical and versatile technique for constructing embankments and slip repairs when a steep face angle is required. In fact, slopes of any required face angle may be built. Environmental constraints and rising land costs have increased the need for value engineering, frequently requiring the engineer to make use of poor quality soils as fill materials. Therefore, reinforced soil slopes provide an economic solution and give engineers the confidence to create structures with a bio-engineered finish. TENSAR INTERNATIONAL SUPPORT SERVICES Tensar International’s experienced engineers are available to provide clients, consultants and contractors with design and construction support. Designs are carried out using sophisticated software developed in-house: • Geogrid layout is designed using the program Winwall, which includes a number of well established design methods • Overall stability can be checked using the program Winslope • Earthquake forces, complex geometry, water tables may all be taken into account

Free Application Suggestions are prepared on the basis of internationally accepted standards such as BS 8006, HA 68/94 and the German Institut für Bautechnik method.

The services offered range from a free of charge application suggestion to a full design and supply service with professional indemnity cover. No liability in negligence or responsibility of any kind is accepted by Tensar International for any project where Tensar products are not used.

STABILISING A STEEP SLOPE This enables engineers to: • maximise the plateau area on a sloping site • widen road or rail embankments for additional capacity within the current boundary • form both environmental noise bunds and screens • utilise cohesive, marginal or other site-won fills • construct low cost temporary works • reduce construction times

TENSAR RE GEOGRIDS FOR REINFORCED SOIL EMBANKMENTS

Tensar geogrids have been awarded numerous independent fitness-for-purpose certificates.

Slopes up to 45°

Heavy compactors can work close to the face of a 1:1 slope.

The unique structure of Tensar uniaxial geogrids enables load from the soil to be transferred to the reinforcement very efficiently. As a result, stability at the face is achieved without the need for containment. Construction is simple and cost-effective because the geogrids, which terminate at the face, are simply placed in horizontal layers on top of compacted fill. A permanent erosion control mat will help the surface vegetation protect the slope from heavy rainfall. The mat reinforces the root zone of the vegetation and maintains an attractive finish to the surface of the slope. TENSAR UNIAXIAL GEOGRIDS ALLOW: • shorter construction times and cost savings

Slip repairs Slip failures in natural or man-made slopes can be repaired by excavating and re-using the failed soil reinforced with Tensar geogrids. This excellent method is more cost-effective and less time consuming than disposing of the failed soil and replacing it with imported fill. THIS METHOD ALSO: • minimises disposal of on-site fill and soils • reduces haulage costs • cuts costs compared to traditional methods by up to 75% • reduces traffic disruption and lane closures

• no face stability problems with heavy compaction equipment • easy, accurate face trimming after construction • attractive appearance with creepers, shrubs and bushes • utilisation of site-won fills

A slope that should have been reinforced.

The geogrids are used extensively for slip repairs, particularly with clay soils (UK).

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Slopes steeper than 45° For steeper slope angles, fill must be contained at the face to create a satisfactory and durable structure. This may be achieved very simply by wrapping the geogrid up the face and connecting it to the layer above using a construction process known as wraparound. This is commonly done using soil filled bags behind the geogrid to help retain the soil during construction and maintain the required shape of the slope face. The bags may be filled with grass seed and topsoil to create a well vegetated face and prevent loss of soil from the steeply inclined slope through erosion. As an alternative to wrap-around, steel mesh panels may be used to form the slope face. The steel mesh supports the fill during placement, and maintains the required face alignment and shape. Turf blocks and ivy provide an attractive easy-to-manage face (UK).

70º slope (Malaysia).

Vegetation develops quickly on slopes constructed with soil-filled bags (Taiwan). Such structures can be designed to withstand seismic loadings.

Wrap-around facings The use of wrap-around offers a simple construction method for a reinforced soil structure. The bags may be filled with top soil for subsequent planting or turfing to provide an attractive face. The system is equally suitable for temporary works where a complicated shape may be readily formed. • suitable for construction over soft ground so avoiding expensive foundations Constructing steep highway slopes (Taiwan).

• construction technique allows tensioning of the geogrid to avoid face slump

Construction requires only geogrid and readily available equipment and materials.

• can create a face using a single fill material • resistant to ultra violet light • removal costs are low for a temporary structure

Typical appearance on completion of construction.

Vegetation takes over to give a mature appearance and hide all the construction detail.

Mature 70º wrap-around slope (Malaysia).

5 Tensar reinforced slopes and walls can accommodate intense dynamic loads (Germany).

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SMP-faced structures are ideal for temporary works.

Steel Mesh Panel (SMP) Systems A steel mesh panel system acts as a construction expedient and as a permanent shutter, providing greater control over face alignment. This low cost option is suitable for both permanent and temporary structures and can be adopted with a variety of face types. A STEEL MESH PANEL SYSTEM OFFERS MANY ADVANTAGES SUCH AS:

The geogrid lengths are simply and securely connected to the steel panels from within the structure.

• a good method of achieving a straight face • avoids slumping as face can be tensioned • quick and easy to erect • construction can be solely from the fill side • can be used with turf or pre-seeded mats for a green face

A vegetated face can be achieved using a thin turf liner behind the steel mesh.

• geotextile can be placed in the face to allow planting at a later date • ideal method for temporary works

Steel mesh panel Typically 50o to 70o

Tensar geogrid

Typical of the vegetated effect achieved with SMP-faced structures (UK).

HDPE bodkin

Turf liner Topsoil

Tensioning the geogrid.

Geotextile placed behind face for planting at later date.

Tensar RE geogrid specifications Tensar geogrid - typical characteristics and dimensions Property

Units Polymer

40RE

55RE

80RE

120RE

160RE

HDPE

HDPE

HDPE

HDPE

HDPE

Minimum carbon black (1)

%

2

2

2

2

2

Roll width

m

1.0 & 1.3

1.0 & 1.3

1.0 & 1.3

1.0 & 1.3

1.0 & 1.3

Roll length

m

50

50

50

50

30

Unit weight

kg/m2

0.34

0.42

0.60

0.94

1.26

Roll weight

kg

19 & 24

23 & 29

32 & 41

49 & 63

40 & 51

Dimensions AL

mm

235

235

235

235

230

AT

mm

16

16

16

16

16

BWT

mm

16

16

16

16

16

FWL

mm

6

6

6

6

6

tB

mm

1.8 - 2.0

2.5 - 2.7

3.4 - 3.7

5.5 - 5.9

7.1 - 7.7

tF

mm

0.7

0.9

1.3

2.0

2.6

tULT (2)

kN/m

52.5

64.5

88.0

136.0

173.0

Load at 2% strain (2)

kN/m

12.7

16.1

23.7

38.0

52.5

Load at 5% strain (2)

kN/m

24.7

30.9

45.2

75.5

103.0

Quality control strength

Approx strain at tULT

%

11.5

11.5

11.5

11.5

11.5

%

100

100

100

100

100

PC or TCR for 10ºC (5)

kN/m

23.3

28.7

38.2

54.6

69.4

PC or TCR for 20ºC (5)

kN/m

20.7

25.5

34.0

48.7

61.7

Junction strength (3) Long term creep rupture strength ULS (4)

(1) Carbon black inhibits attack by UV light. Determined in accordance with BS 2782:Part 4:Method 452B:1993. Any section of grid fully exposed to sunlight can be expected to retain 90% of its quality control strength for periods in excess of 40 years in temperature climates and 20 years in tropical climates. (2) Determined in accordance with BS EN ISO 10319:1996 and as lower 95% confidence limit in accordance with ISO 2602:1980 (BS 2846:Part 2:1981). (3) Determined in accordance with GRI Test Method GG2-87, and expressed as a % of the quality control strength. (4) Determined as a lower bound using standard extrapolation techniques to creep rupture data obtained following the test procedure in BS EN ISO 13431:1999 for 120 year design life. (5) In-soil temperature. (6) Tensar RE geogrids are inert to all chemicals naturally found in soils and have no solvents at ambient temperature. They are not susceptible to hydrolysis and are resistant to aqueous solutions of salts, acids and alkalis (pH 2.0 to 12.5) and are nonbiodegradable. (7) All quoted dimensions and values are typical unless stated otherwise. Data sheets are also available for 60 year creep rupture strengths and Tensar SR geogrids.

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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 • Steep Slopes Constructing embankments with steep slopes • Retaining Walls Constructing retaining walls in reinforced soil • Foundations over Piles Constructing over weak ground without settlement • Basal Reinforcement Constructing embankments over weak ground • Railways Reinforcing ballast 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:

Tensar International Limited

Tel: +44 (0)1254 262431

New Wellington Street

Fax: +44 (0)1254 266868

Blackburn BB2 4PJ United Kingdom

E-mail: [email protected] www.tensar-international.com

Tensar geogrids are manufactured under tightly controlled conditions. The quality assurance procedures covering design and application and the manufacturing process have been certified by the British Standards Institution as a Registered Firm in accordance with BS EN ISO 9001:2000 Q05288

Tensar is a registered trade mark. ©Copyright Tensar International Limited Printed December 2002 Issue 4, 79010020

The information provided verbally, or in this document or as a Free Application Suggestion is of an illustrative nature and is supplied without charge. It does not form any contract or intended contract with the user. No liability in negligence will arise from the construction of any project based on such information or material. Final determination of the suitability of any information or material for the use contemplated and the manner of use is the sole responsibility of the user and the user must assume all risk and liability in connection therewith.