This document discusses geotextiles and geogrids. It defines geotextiles as permeable geosynthetics made of textiles that are used in construction to provide functions like separation, filtration, drainage, and reinforcement. Geogrids are defined as structurally sound grids made of extruded bars used to reinforce soils in applications like roads, retaining walls, and embankments. The document provides examples of using geotextiles for separation and geogrids for reinforcement in challenging soil conditions for various construction projects.

1. Geotextile Separation & Geogrid Reinforcement
P.O.Box 87532 Mombasa 80100, Kenya | Moushmi Complex, Ground Fl, Nyoka Road, Nyali
+254 (0) 722 410 221 / +254 (0) 733 711 781 | info@geotextileseastafrica.com
www.geotextileseastafrica.com

2. Geotextile
Definition:
A permeable geosynthetic comprised solely of textiles. Geotextiles
are used with foundation, soil, rock, earth, or any other
geotechnical engineering-­‐related material as an integral part of a
human made project, structure, or system (ASTM D4439).
Functions of Geotextiles:
Separation,
Filtration,
Drainage
Reinforcement
Protection

4. Why do we use Geotextiles in separation?

6. To prevent mixing of construction
Layers
To increase bearing capacity by
avoiding material loss into the
Subgrade
To improve the compaction properties
of the aggregate layer
To provide long-­‐term stability of
foundation layers
?

7. Fibertex Geotextiles Functions
Separation
Loss of Aggregate
Aggregate Retained

8. Elongation Tensile strength
Mechanical properties
Separation

9. Puncture
Resistance
Mechanical properties
Separation

10. Required Hydraulic properties
Separation

11. Cost savings from using Separation
0.00 0.50 1.00 2.502.001.50 3.00
0
20
40
100
80
60
120
%ofDesignAggregateThickness
CBR
Aggregate loss to weak subgrade
(FHWA 1989)

12. Heavy-­‐Grade Nonwoven Geotextile Over a Low-­‐Bearing Capacity Soil (marshland)
Geotextile Separation : Examples

14. Temporary Site Access
Example: Geotextile used as separation & reinforcement over low-­‐bearing capacity soil (swamp)

15. Geogrid
Definition:
a structurally sound and stable grid for soil reinforcement,
manufactured of extruded and drawn bars, laid and welded solid
together.
Applications of Geogrids:
Geogrids provide tensile reinforcement for base courses in:
-­‐ Roads (paved & unpaved), airports & runways, railway and highway
foundation engineering
-­‐ steep sided soil embankments and retaining walls, foundation
reinforcement of earth embankments
-­‐ load transfer of overlying soil masses, spanning voids and sink holes,
sludge lagoon closures, trench covers and beds.

16. base course reinforcement roads
Combigrid + Secugrid geogrids

17. 140 MW windfarm in Dobrogea , SE of Romania
Case Study Salbatica II windfarm Romania

18. Quelle: REpower Systems AG
Access road to site; low-­‐bearing capacity soils...
(without geotextile for soil separation & geogrid for soil reinforcement)

19. The crushed stone is dumped from the trucks , spreaded and compacted
Geosynthetic Solution: Combigrid (2-­‐in-­‐1 solution; a composite
product of a Secugrid geogrid, with a nonwoven geotextile firmly welded
between the reinforcement bars for soil stabilisation, separation and filtration
applications)

20. Flensburg
Füssen
Nesselwang
Füssen
BAB A7:
Flensburg Nesselwang
945,6 km
= the longest
german Highway
Case Study German Autobahn

21. The soil and foundation conditions of the project were as
follows:
flat willow areas with in-situ peat and sea cretaceous with
pulpy to soft consistency beneath
high moor areas/moor willows with thicknesses of upto 4m,
under the top ground surface there were layers of pulpy to
soft sea cretaceous.
groundwater appx. 0.1m above top ground surface

22. Year of construction 2003/2004

23. Subsoil improvement with geosynthetics
The project included the preparation of the drainage trenches,
foundation of the dams and noise barriers and subsoil
improvement.
Due to the subsoil with its low bearing capacity in large depths,
the dams and the subsoil improvement were reinforced with
geosynthetics and built as a floating mattress.
For levelling and the reduction of the expected long-­‐term
settlements of the peat, the peat was completely removed in
certain areas and the subsoil was improved with crushed stone of
the grain size 2/150mm.

26. Examples of geogrids rolled out over various
soil conditions:

28. NAUE Tragschichtbewehrungen

29. Advantages of Geogrids:
cost saving alternative to conventional construction methods
very high strength at low strains
immediate interlocking effect
low creep characteristics (PET)
high angles of friction due to the structured geogrid surfaces
high resistance against installation damage
4.75 m wide rolls
made from uniformly extruded solid PET or PP bars
high resistance against biological and chemical attack
biaxial geogrid strengths up to 80 kN/m
uniaxial geogrid strengths up to 400 kN/m
quick and easy to install

30. Alternative solutions for temporary roads:
GREENCELLS: made up of alternately joined geotextile strips to form a
continuous square cellular mat section which is filled with earth, gravel or
concrete & used to stabilize embankments, river banks, sand dunes, base
courses & canals

31. P.O.Box 87532 Mombasa 80100, Kenya | Moushmi Complex, Ground Fl, Nyoka Road, Nyali
+254 (0) 722 410 221 / +254 (0) 733 711 781 | info@geotextileseastafrica.com
www.geotextileseastafrica.com
Thank you !