Geo-Synthetics
Perspective in 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
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
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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
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 ( 400 ROB constructed per year)
Application In Railway (General)
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Steep Slope Construction ( Non Railway Loading)
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Embankment Slip repairs
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Construction of high banks on soft soil (PVD)
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Erosion control of slope
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Protection against rock falls
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
12
Application In Railway (Specific)
 Track Bed Design
 Reinforced Earth Embankment (Railway Loading )
Formation Rehabilitation
GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
USES OF GEO-GRID
GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
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.
Geo-grid+Geotextile 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 app 2000 km track.
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
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.
 RDSO has drafted the Specification for
geo-synthetics which is under active
consideration of Railways
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.