Geo-Synthetics Specifications for Railway Sector Rajesh Agarwal, Director, RDSO
� 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
�
Geotechnical Directorate
� Deals with R & D of soil mechanics – for the
use of Railways in
� Formations
�Cuttings
�Ground improvement
�RE wall constructions ( ROB )
Introduction
� 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 � 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
Scope for use of geosynthetics
Vision 2020
� 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.
� 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
Application In Railway (General)
15
Typical Cross Section of Embankment with Prefabricated Vertical Band Drains
Sand
Blanket Initial
Embankment
Soft
Clay
Layer
Band
drains
Firm
Soil
� Track Bed Design
� Reinforced Earth Embankment (Railway
Loading )
� Formation Rehabilitation
Application In Railway (Specific)
Geotechnical Directorate
Locations Specification requirement
Formations To be designed for Rly Loadings
Cuttings 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 � Geotextiles between blanket and prepared
subgrade if prepared subgrade has fines more than 15%
Existing Track � 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 � Geotextiles between blanket and prepared
subgrade if prepared subgrade has fines more than 15%
Existing Track � 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 � Geotextiles between Ballast & sub-ballast
� Geotextiles beneath sub-ballast
� Erosion Control on slopes
Existing Track � For Formation Rehabilitation
Specifications and scope for use of geo-synthetics in World Railways
Australian Railways Reconditioning Guidelines RTS3430
Existing Track � Geotextiles and Geogrids for Formation
Rehabilitation
Specifications and scope for use of geo-synthetics
Indian Railways (specific to railway use) � Jute geotextiles ( for erosion control) Issued � Geo-grids under trial
� Geotextiles (beneath track & slope protection) under preparation
Jute Geo-Textile
� Guidelines for application of Jute Geo-textile in
Railway Embankment & Hill slopes issued for erosion control.
� 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
� 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 in IR
Geo-grid+Geo-textile on IR
� 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
� Field trials for formation rehabilitation Geo-
grid in SCR
� 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)
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 Property Test Method Values
1 Material of Geo-grid
• 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 GRI-GG1-87
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
Item
Property Test Method
Values
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
Geotechnical
Engg./RDSO 36
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
300 g/m2 (Minimum)
3 Thickness of Fabric at 2 Kpa ASTM 5199 2.0 mm (minimum)
4 Roll width 5.0 metre (minimum).
5 Roll Length 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
1 Apparent opening size O95
IS: 14294 / ASTM D 4751 /
EN ISO: 12956 40 to 85 microns
2 Water Flow Rate Normal to the Plane
IS 14324 / ASTM D 4491
20 lit. /m2/s (minimum)
Specification of Non-woven Geo-textile
Geotechnical
Engg./RDSO 37
SL Property Test Method Values
1 Polymer Polypropylene/ High Density Polyethylene/ polyamide/ polyester or similar polymer
2 Mass per unit area IS: 14716 / ASTM D: 3776
240 g/m2 (Minimum)
3 Thickness at 2 Kpa ASTM: 5199 0.65 mm (minimum)
4 Roll width 5.0 metre (minimum)
5 Roll Length 50 m (minimum)
Mechanical Properties
1 Tensile Strength
Warp IS: 1969 / ASTM D 4595 / EN ISO: 10319
40kN/m (Minimum)
Weft 35kN/m (Minimum)
2 Elongation at Maximum Load
Warp IS: 1969 / ASTM D 4595 / EN ISO: 10319
15%-30 %
Weft 15%-30 %
3 Puncture Strength IS: 13162 / ASTM D: 4833
600 N (Minimum)
Hydraulic Properties
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
15 lit. /m2/s (minimum)
Specification of woven geo-textile
�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)
General Issues
� Specification- Generic in nature
�To avoid monopoly
�Material to be readily available (Time
constraint)
� Cost effective
�Should be competitive with Alternates
�Research with Blending of Jute with PP etc.
being explored by Railways
Issues concern
� Testing facilities
�Contracts to be awarded division wise & to be
passed by divisional authorities
�How testing of material to be monitored
� 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
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
� 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.
Geotechnical
Engg./RDSO 51
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
320 g/m2(minimum)
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)
Mechanical Properties
1. Ultimate Tensile Strength (MD) IS: 13162 part 5 & IS: 13325 /
ASTM D 6637 / BS EN ISO: 10319
30 kN/m (minimum)
Ultimate Tensile Strength (CD) 30 kN/m (minimum)
2. Strain at Ultimate Tensile Strength (MD) IS: 13162 part 5 & IS: 13325 /
ASTM D 6637 / BS EN ISO: 10319
8 - 15%
Strain at Ultimate Tensile Strength (CD) 8 - 15%
3. Creep limited strength for 15 years period at 300
C temperature (MD and CD) ASTM D5262 / ASTM D6992 / ISO 13431
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.
3. MD stands for Main Direction & CD stands for Cross Direction.