1. Geo-Synthetics Perspective in 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
Latest Major 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. Scope for use of geosynthetics
Vision 2020
New Lines km route expansion
DFC- Western & Eastern Corridor
Double/Multiple lines – Kms

7. 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.

8. Scope for use of geosynthetics
ROB/RUB
Road Over Bridge ( 400 ROB constructed per year)

9. Application In Railway (General)
Steep Slope Construction ( Non Railway Loading)
Embankment Slip repairs
Construction of high banks on soft soil (PVD)
Erosion control of slope
Protection against rock falls
Application In Railway (General)

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

11. Construction of RE Embankment

12. Typical Cross Section of Embankment with Prefabricated Vertical Band Drains
Sand Blanket
Initial Embankment
Band drains
Soft Clay Layer
Firm Soil 12 12

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

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

15. GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION

16. Geo-grid in IR
Biaxial geogrid 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 Geogrid.

17. Geo-grid+Geotextile 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.

18. 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)

19. Geo-grids
40X40 mm To 60X60 mm aperture size are not available for trial
These sizes may be provided/manufactured.
Scope- Early Rehabilitation of app 2000 km track.

20. 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)

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

22. Road Over Bridge With Retaining Wall

23. Road Over Bridge With Reinforced Earth Wall

24. 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

25. 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

26. Project on 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.

27. RDSO has drafted the Specification for geo-synthetics which is under active consideration of Railways

28. THANKS

29. 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.

30. 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 30

31. 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.

32. 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.