1. Geo-Synthetics Specifications for Railway Sector
Rajesh Agarwal, Director, RDSO

2. 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

3. Geotechnical Directorate
Deals with R & D of soil mechanics – for the use of Railways in
Formations
Cuttings
Ground improvement
RE wall constructions ( ROB )

4. 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)

5. 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

6. Functions of Geosynthetics
Separation
Filtration

7. Functions of Geosynthetics
Reinforcement
Drainage

8. Functions of Geosynthetics
Barrier

9. Scope for use of geosynthetics
Vision 2020
New Lines km route expansion
DFC- Western & Eastern Corridor
Double/Multiple lines – Kms

10. 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.

11. Scope for use of geosynthetics
ROB/RUB
Road Over Bridge ( 600 ROB constructed per year)

12. 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
Application In Railway (General)

13. Use of Synthetic Geogrids for Erosion Control of Natural Existing Slopes

14. Construction of RE Embankment

15. Typical Cross Section of Embankment with Prefabricated Vertical Band Drains
Sand Blanket
Initial Embankment
Band drains
Soft Clay Layer
Firm Soil 15 15

16. Application In Railway (Specific)
Track Bed Design
Reinforced Earth Embankment (Railway Loading )
Formation Rehabilitation

17. GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
USES OF GEO-GRID

18. GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION

19. Geotechnical Directorate
Locations
Specification requirement
Formations
To be designed for Rly Loadings
Cuttings
No issue with Rlys
Ground improvement
RE wall constructions ( ROB)

20. 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

21. 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

22. 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

23. Specifications and scope for use of geo-synthetics in World Railways
Australian Railways
Reconditioning Guidelines RTS3430
Existing Track
Geotextiles and Geogrids for Formation Rehabilitation

24. 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

25. 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

26. 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

27. 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: (Part V)
Load at 2% & 5% strain
IS: 13162(Part V)
Strain at Ultimate Tensile Strength

28. 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

29. 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.

30. 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.

31. 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)

32. 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 km track.

33. 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)
mm – Square (preferably 35mmx35mm)
mm – Square (preferably 45mmx45mm)
mm – Square (preferably 55mmx55mm)
mm x mm – Rectangular
mm x 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)

34. Mechanical Properties & other Tests
Item
Property
Test Method
Values
5.1
Ultimate Tensile Strength
(MD & CD)
IS: part 5 & IS: 13325/ASTM D 6637/BS EN ISO: 10319
Two types
20 kN/m (minimum)
30 kN/m (minimum)
5.2
Strain at Ultimate Tensile
Strength
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
strain)(Non Essential Test)
ISO 10319: 1996

35. Item
Property
Test Method
Values
6.5
Resistance to chemical degradation
(Non Essential Test)
EPA 9090
6.6a
Resistance to UV Light Weathering
ASTM D4355
6.6b
Carbon Black Test (where applicable as per polymer type material)
BS2782 Part-4 Method, 452B: 1993
6.7
Creep limited Strength for 15 years period at 30° C temp.
(MD & CD)
ASTM D 5262/ASTM D6992/ISO 13431

36. Specification of Non-woven Geo-textileSL
Property
Test Method
Values 1
Polymer
Polypropylene/ High Density Polyethylene/ polyamide, polyester or similar polymer 2
Weight/Mass per unit area
IS: /
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
Elongation at break
IS: /
ASTM D 4595 /
EN ISO: 10319
40 % to 70 %
Tensile Strength
IS: / ASTM D 4595 /
15 kN/m (minimum)
Hydraulic Properties
Apparent opening size O95
IS: / ASTM D 4751 /
EN ISO: 12956
40 to 85 microns
Water Flow Rate Normal to the Plane
IS /
ASTM D 4491
20 lit. /m2/s (minimum)
Geotechnical Engg./RDSO

37. Specification of woven geo-textileSL
Property
Test Method
Values 1
Polymer
Polypropylene/ High Density Polyethylene/ polyamide/ polyester or similar polymer 2
Mass per unit area
IS: /
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
Tensile Strength
Warp
IS: 1969 /
ASTM D 4595 /
EN ISO: 10319
40kN/m (Minimum)
Weft
35kN/m (Minimum)
Elongation at Maximum Load
15%-30 %
Puncture Strength
IS: /
ASTM D: 4833
600 N (Minimum)
Hydraulic Properties
Apparent opening size O95
IS /
ASTM D: 4751 /
EN ISO: 12956
425 microns (maximum)
Water Flow Rate Normal To The Plane
IS: 14324/
ASTM D: 4491
15 lit. /m2/s (minimum)
Geotechnical Engg./RDSO

38. 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)

39. Road Over Bridge without Reinforced Earth Wall (Conventional ROB)

40. Road Over Bridge With Retaining Wall

41. Road Over Bridge With Reinforced Earth Wall

42. 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

43. Issues concern Testing facilities Works contract/Supply contract
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

44. 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

45. THANKS

46. 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.

47. 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 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 47

48. 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.

49. 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.

50. 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.

51. Specification of Geo-gridSN
Property
Test Method
Values 1
Polymer
Polypropylene/Polyester or similar polymer 2.
Mass per unit area
IS: /
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: part 5 & IS: /
ASTM D 6637 /
BS EN ISO: 10319
30 kN/m (minimum)
Ultimate Tensile Strength (CD)
Strain at Ultimate Tensile Strength (MD)
8 - 15%
Strain at Ultimate Tensile Strength (CD)
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.
Geotechnical Engg./RDSO