Geo-Synthetics
Specifications for Railway
Sector
Rajesh Agarwal, Director, RDSO
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RDSO – Research Design & Standard Organization
Only R & D organization of IR
Deals from Track formation to Bridges to Coaches to signal
to OHE
Made specifications of products for Railway Use
Latest Achievements includes
 AC Double Decker Coach
 4500 HP Hotel load locomotive
 Video Surveillances for running train
 Designing of Track including formation for HAL
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Geotechnical Directorate
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Deals with R & D of soil mechanics – for the
use of Railways in
 Formations
 Cuttings
 Ground
improvement
 RE wall constructions ( ROB )
Introduction
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Geosynthetics :Generally Polymer based Polypropylene, Polyester, PVC, Polyamide,
Polyethylene
Various types of Geosynthetics can be used in
Railways
 Geotextiles
 Geogrids
 Geonets
 Geocell
 Geomembranes
 Geocomposites
 Prefabricated Vertical
Drains (Band Drains)
Functions of Geosynthetics
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Geo-synthetics can perform one or several functions
to improve mechanical or hydraulic behaviour of the
Railway Formations (Base structure)
The basic functions performed by geo-synthetics are:
Separation
Filtration
Drainage
Reinforcement
Barrier
Basal Layer
Functions of Geosynthetics
Separation
Filtration
Natural Soil
Geo-textile
Water Flow Direction
Granular Soil
Functions of Geosynthetics
Reinforcement
Drainage
Functions of Geosynthetics
Barrier
Scope for use of geosynthetics
Vision 2020
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New Lines -- 25000 km route expansion
DFC- Western & Eastern Corridor
Double/Multiple lines – 30000 Kms
Need for Use of Geo-Synthetics
Existing Lines
• Indian Railways is upgrading infrastructure to
meet future demand of growing traffic.
• Geosynthetics
can
also
be
used
in
rehabilitation/strengthening of existing weak
formation of length about 700 kms PR & 2000km
TSR.
Scope for use of geosynthetics
ROB/RUB
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Road Over Bridge ( 600 ROB constructed per year)
Application In Railway (General)
 Steep Slope Construction ( Non Railway Loading)
 Construction of high banks on soft soil (PVD)
 Erosion control of slope
 Protection against rock falls
 ROB for Road Loading
Use of Synthetic
Geogrids for Erosion
Control of Natural
Existing Slopes
Construction of RE Embankment
Typical Cross Section of Embankment
with Prefabricated Vertical Band Drains
Initial
Embankment
Soft
Clay
Layer
Sand
Blanket
Band
drains
Firm
Soil
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Application In Railway (Specific)
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Track Bed Design
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Reinforced Earth Embankment (Railway
Loading )
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Formation Rehabilitation
GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
USES OF GEO-GRID
GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
Geotechnical Directorate
Locations
Formations
Cuttings
Specification requirement
To be designed for Rly Loadings
No issue with Rlys
Ground improvement
No issue with Rlys
RE wall constructions ( ROB) No issue with Rlys
Specifications and scope for use of
geo-synthetics in World Railways
European Railways (UIC)
Code 719 R
New Construction
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Geotextiles between blanket and prepared
subgrade if prepared subgrade has fines
more than 15%
Existing Track
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Geotextiles and geogrids for Formation
Rehabilitation
Specifications and scope for use of
geo-synthetics in World Railways
European Railways (UIC)
Code 719 R
New Construction
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Geotextiles between blanket and prepared
subgrade if prepared subgrade has fines
more than 15%
Existing Track
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Geotextiles and geogrids for Formation
Rehabilitation
Specifications and scope for use of
geo-synthetics in World Railways
American Railways
AREMA Manual Part 10
New Construction
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Geotextiles between Ballast & sub-ballast
Geotextiles beneath sub-ballast
Erosion Control on slopes
Existing Track
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For Formation Rehabilitation
Specifications and scope for use of
geo-synthetics in World Railways
Australian Railways
Reconditioning Guidelines RTS3430
Existing Track
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Geotextiles and Geogrids for Formation
Rehabilitation
Specifications and scope for use of
geo-synthetics
Indian Railways (specific to railway use)
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Jute geotextiles ( for erosion control) Issued
Geo-grids under trial
Geotextiles (beneath track & slope protection) under
preparation
Jute Geo-Textile
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Guidelines for application of Jute Geo-textile in
Railway Embankment & Hill slopes issued for
erosion control.
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Guidelines no. RDSO/2007/GE : G-0008
Use of IS of geo-synthetics by IR
Geo Jute
All properties is to be checked with IS codes
Properties
Test Method (IS)
Weight (gsm)
IS: 2387
Maximum length & width
IS: 1954
Ends/dm & picks/dm
IS: 1963
Thickness
IS: 7702
Aperture size
IS: 2405
Minimum Breaking Load
IS:1969
Maximum Elongation at
Break
IS: 1969
Use of IS of geo-synthetics by IR
Geo Grid
All properties is to be checked with IS codes
Properties
Test Method (IS)
Mass per unit area
IS: 14716
Ultimate Tensile Strength
IS: 13162 (Part V)
Load at 2% & 5% strain
IS: 13162(Part V)
Strain at Ultimate Tensile Strength
IS: 13162(Part V)
Use of IS of geo-synthetics by IR
Geo Textiles
All properties is to be checked with IS codes
Properties
Test Method (IS)
Mass per unit area
IS: 14716
Tensile Strength
IS 13162
Elongation at break
IS: 13162
Apparent opening size
IS: 14294
Water flow rate normal to
the plane
IS: 14324
Geo-grid in IR
 Biaxial geo-grid has been used in South Central
Railway, Northern Railway (Polypropylene – strength
30 kN/m with aperture size of 61mm x 61mm) has
been used for formation rehabilitation/strengthening.
 Observations in field at SCR & NR have indicated
improvement of overall track performance after the
application of Geo-grid.
Geo-grid+Geo-textile on IR
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NF Railway also tried use of Geo-grid (Polyester based –
knitted & coated with strength of 40 kN/m & aperture size
of 25mmx25mm) in combination of geo-textile and sand
layer for formation rehabilitation.
The performance report of the trial section of NF Railway
is satisfactory.
For low density routes, geotextile along with sand layer and brick
soling has been used in Sitamarhi – Darbangha project, ECR.
Geo-grids
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Field trials for formation rehabilitation Geogrid in SCR
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Issues involved for optimum benefit
Aperture size ( As per ballast size if IR)
 Junction strength (As per Axle load)
 Material type (As per Soil/Atmospheric condition)
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Geo-grids
40X40 mm to 60X60 mm aperture size are not
available for trial.
These sizes may be provided/manufactured.
Scope- Early Rehabilitation of approx. 2000 km track.
Specifications of Geogrids for Extended Trials on South Central Railway
Item
1
Property
Material of Geogrid
Test Method
•
•
Values
Any organic polymer based material to provided
required
mechanical
properties
(like
Polypropylene/Polyester/HDPE or similar polymer).
Atleast, both Polypropylene and Polyester geo-grid
material must be used in trial.
2
Aperture size
(clear)
1. 30-40 mm – Square (preferably 35mmx35mm)
2. 40-50 mm – Square (preferably 45mmx45mm)
3. 50-60 mm – Square (preferably 55mmx55mm)
4. 30-40 mm x 60-65 mm – Rectangular
5. 40-50 mm x 60-65 mm – Rectangular
Aperture sizes of geo-grid of square/rectangular shape
in each above group should differ atleast by 8-10mm.
3
Roll width
As per requirement of width attachment to fit with BCM,
in the range 3.8m to 4.0m.
4
Roll length
50 m (Minimum)
Mechanical Properties & other Tests
Item
Property
Test Method
Values
5.1
Ultimate Tensile Strength
(MD & CD)
IS: 13162 part 5 & IS:
13325/ASTM D
6637/BS EN ISO:
10319
Two types
1. 20 kN/m
(minimum)
2. 30 kN/m
(minimum)
5.2
Strain at Ultimate Tensile
Strength
(MD & CD)
IS: 13162 part 5 & IS:
13325/ASTM D
6637/BS EN ISO:
10319
8-5% (Range)
5.3
Junction Efficiency (CD & MD)
(Non Essential Test)
GRI-GG2-87 and GRIGG1-87
Desirable 95%
(Test to be done
prior to insertion)
Non Essential Tests : These tests are to be conducted on geo-grid samples before
laying and test values are to recorded for further decision.
6.1
Radial stiffness at low strain
(@0.5% strain)(Non Essential
Test)
ISO 10319: 1996
Property
Test
Method
Item
6.5
Resistance to chemical
degradation
(Non Essential Test)
EPA 9090
6.6a
Resistance to UV Light
Weathering
(Non Essential Test)
ASTM D4355
6.6b
Carbon Black Test
(where applicable as
per polymer type
material)
(Non Essential Test)
BS2782 Part-4 Method, 452B: 1993
6.7
Creep limited Strength
for 15 years period at
30° C temp.
(MD & CD)
(Non Essential Test)
ASTM D 5262/ASTM D6992/ISO 13431
Values
Specification of Non-woven Geo-textile
SL
Property
Test Method
Values
1
Polymer
Polypropylene/ High Density Polyethylene/
polyamide, polyester or similar polymer
2
Weight/Mass per unit area
IS: 14716 /
ASTM D: 3776
3
Thickness of Fabric at 2 Kpa
ASTM 5199
4
Roll width
5.0 metre (minimum).
5
Roll Length
300 g/m2
(Minimum)
2.0 mm (minimum)
50 m (minimum)
Mechanical Properties
1
Elongation at break
IS: 13162 /
ASTM D 4595 /
EN ISO: 10319
40 % to 70 %
2
Tensile Strength
IS: 13162 / ASTM D
4595 /
EN ISO: 10319
15 kN/m (minimum)
Hydraulic Properties
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1
Apparent opening size O95
IS: 14294 / ASTM D
4751 /
EN ISO: 12956
2
Water Flow Rate Normal to the
Plane
IS 14324 /
ASTM D 4491
40 to 85 microns
20 lit. /m2/s
Geotechnical
(minimum)
Engg./RDSO
Specification of woven geo-textile
SL
Property
Test Method
1
Polymer
2
Mass per unit area
IS: 14716 /
ASTM D: 3776
3
Thickness at 2 Kpa
ASTM: 5199
4
Roll width
5.0 metre (minimum)
5
Roll Length
50 m (minimum)
Values
Polypropylene/ High Density Polyethylene/
polyamide/ polyester or similar polymer
240 g/m2 (Minimum)
0.65 mm (minimum)
Mechanical Properties
1
Tensile Strength
Warp
Weft
2
40kN/m (Minimum)
IS: 1969 /
ASTM D 4595 /
EN ISO: 10319
15%-30 %
35kN/m (Minimum)
Elongation at Maximum Load
Warp
Weft
3
IS: 1969 /
ASTM D 4595 /
EN ISO: 10319
Puncture Strength
15%-30 %
IS: 13162 /
ASTM D: 4833
600 N (Minimum)
Hydraulic Properties
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1
Apparent opening size O95
IS 14294 /
ASTM D: 4751 /
EN ISO: 12956
425 microns (maximum)
2
Water Flow Rate Normal To The
Plane
IS: 14324/
ASTM D: 4491
Geotechnical
15 lit. /m2/s (minimum)
Engg./RDSO
Reinforced Earth Design for Railway Loading
By KRCL in USBRL Projects
Bridge no 40 at Riasi
Bank of 16m to 56 m high
Design Approved by IIT/D
Cost effective (whether or not)
Road Over Bridge without Reinforced Earth Wall (Conventional ROB)
Road Over Bridge With Retaining Wall
Road Over Bridge With Reinforced Earth Wall
General Issues
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Specification- Generic in nature
 To avoid monopoly
 Material to be readily available (Time
constraint)
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Cost effective
 Should be competitive with Alternates
 Research with Blending of Jute with PP etc.
being explored by Railways
Issues concern
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Testing facilities
 Contracts
to be awarded division wise & to be
passed by divisional authorities
 How testing of material to be monitored
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Works contract/Supply contract
 Railway
prefers works contract
Application of Geo-syntheticis
 Analysis of behavior of different Geo-synthetics to
be used in Railway Formations
 Validation through Lab model,
 FEM model
 And site measurements etc.
 Draft Guidelines For Geo-synthetics Prepared & under active
discussion with in Railway
THANKS
Other Use Of Geosyntheticis in IR
Different Zonal Railways may be use the
Geosynthetic on their railway as per requirement
and site conditions such as:
Steep Slope Construction, Embankment Slip
repairs, Construction of high banks on soft soil
(PVD), Erosion control of slope And Protection
against rock falls etc.
Formation treatment with blanket &
geotextile by formation rehabilitation m/c
The limitations of Indian railways
 The formation rehabilitation m/c very costly
 Line Block Requirement - 6 to 8 Hrs.
(Very difficult for running track)
 Progress very slow- 300 to 400 m per day
 Geotextile life is very short 4 -5 years, Indian Railway
want long life such as 10 to 15 years.
 Cost effectiveness - Cost consideration not match
QUALITY ASSURANCE & QUALITY
CONTROL PLAN FOR GEOSYNTHETICS
The manufacturer must have in house integrated
testing facilities for all the tests as per specifications
to be carried out on the product. The testing
facilities may be more for Geosynthetics in India.
 The Railway Authorities may witness the tests
carried out at independent testing facilities.
CONCLUSIONS
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Geo-synthetics can be used effectively in railway
application for track bed stabilization, track drainage,
erosion control, interface protection, construction over soft
soil, steep slope construction, mud pumping, etc.
Its use is a necessity and cost effective for construction of
new formations & rehabilitate / strengthen the existing
formations for running of heavy axle loads.
The specifications of Geosynthetics items specially
Geogrid for railway application are in evolving stage
worldwide.
IR has gained some experience and RDSO has framed
provisional specifications. These should be tried as per site
conditions.
Extended Field trials are necessary to validate & assess
specifications of geogrids for track bed strengthening.
Need for Use of Geo-Synthetics
New Constructions
• To construct ‘Dedicated Freight Corridors i.e.
Eastern Corridor & Western Corridor’ & ‘High
Speed Corridors to connect the major cities.’
• This requires construction of new stable track
formations suitable for heavy axle loads.
• It is difficult to adopt the present practice in DFC
& High speed which will increase the maintenance
cycles. Hence Railway formation should be
design using geo-synthetics.
Specification of Geo-grid
SN
Property
Test Method
Values
1
Polymer
Polypropylene/Polyester or similar polymer
2.
Mass per unit area
IS: 14716 /
ASTM D: 3776
3.
Aperture size
Square opening of suitable size (suggested size 35mm to 60
mm) such that effective interlocking takes place with the
existing ballast particles. (Size to be decided by PCE
Zonal railway, as per site conditions.)
4.
Roll width
As per site requirement and width attachment to BCM
5.
Roll Length
50 m (minimum)
320 g/m2(minimum)
Mechanical Properties
1.
Ultimate Tensile Strength (MD)
Ultimate Tensile Strength (CD)
2.
Strain at Ultimate Tensile Strength (MD)
Strain at Ultimate Tensile Strength (CD)
3.
Creep limited strength for 15 years period at 30 0
C temperature (MD and CD)
IS: 13162 part 5 & IS:
13325 /
ASTM D 6637 /
BS EN ISO: 10319
IS: 13162 part 5 & IS:
13325 /
ASTM D 6637 /
BS EN ISO: 10319
ASTM D5262 /
ASTM D6992 /
ISO 13431
30 kN/m (minimum)
30 kN/m (minimum)
8 - 15%
8 - 15%
15 kN/m (minimum)
Note: 1. Test method is only indicative which give procedure. However values will govern as
specified above.
2. Long term strength of geogrid with due consideration of creep effect is important as
geogrid is supposed to remain under track for long period say 20 years or more.
Geotechnical
Engg./RDSO
3. MD stands for Main Direction & CD stands for Cross Direction.
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