GEO TEXTILE: PERSPECTIVE FROM THE RAILWAY SECTOR

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GEO TEXTILE PERSPECTIVE FROM THE RAILWAY SECTOR

• A K Shrivastava. Executive Director Railway Board
• Rajesh Agarwal Geo-technical Engineering
  Directorate RDSO
• Presentation on 19.11.2010 at New Delhi

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Introduction

• Geo textile / Geo synthetics a Polymer based
  product of Polypropylene, Polyester, PVC,
  Polyamide, Polyethylene
• Various types of Geo synthetics
• Geo textiles
• Geo grids
• Geo nets
• Geo cell
• Geo membranes
• Geo composites
• Prefabricated Vertical Drains (Band Drains)

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Functions of Geosynthetics

• Geo-synthetics improve mechanical and hydraulic
  behaviour of formations
• Basic functions of geo-synthetics
• Separation
• Filtration
• Drainage
• Reinforcement
• Barrier
• Basal Layer

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RAILWAY TRACK FORMATION

• Railway Track is porous Road
• Varying formation soil across country v/s need of
  uniform track formation response.
• Cumbersome and costly to transport specified soil
  material at all places.
• Specifications of formation, Ballast Blanket
  materials are different from highway
• Geo-synthetic can be an economical aid in
  improving train load carrying capability.
• Geo-synthetic works as separation barrier,
  prevent rutting, ballast puncturing, improve
  soil bearing capacity, distribute load better

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• Steep Slope Construction ( Non Railway
  Loading)
• Embankment Slip repairs
• Construction of high banks on soft soil
• Erosion control of slope
• Protection against rock falls

Application In Railway (General)
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Application In Railway (Specific to railway loading)

• Track Bed Design
• Reinforced Earth Embankment
• Formation Rehabilitation

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Application In RailwayNew Constructions

• Dedicated Freight Corridors
• High Speed Corridors.
• Heavy axle loads / high speed railway track
  require stable track formations.
• Geo-synthetics can help to avoid repeated
  maintenance and provide stable railway formation
• Need to be designed as per site boundary
  condition

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Application In Railway Open-line / Revenue line)

• IR is upgrading infrastructure to meet future
  demand of higher axle load traffic.
• About 700 km track is on weak formation
• cause of ballast penetration, higher fuel
  consumption, passenger discomfort, extra
  maintenance cost to track and rolling stock,
• Rehabilitation / strengthening of such track can
  help to eliminate speed restrictions

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Use of Synthetic Geogrids for Erosion Control of
Natural Existing Slopes
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Construction of RE Embankment
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Typical Cross Section of Embankment with
Prefabricated Vertical Band Drains
Sand Blanket
Initial Embankment
Band drains
Soft Clay Layer
Firm Soil
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Band drains installed above initial embankment
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GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION
USES OF GEO-GRID
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GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION

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PROJECT JAMMU-UDHAMPUR RAIL LINK.

• At km 54/043 near bridge no 162 in Udhampur
  yard, embankment constructed with 35 m height .
• Due to space constraint and close proximity of
  irrigation canal and Tawi river at the bottom of
  hill, not possible to provide designed slope of
  2.5H 1V.
• RE slope was constructed with Uniaxial Geogrid
  of slope of 1.5 H 1V.

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Why do the Industry should develop customized geo synthetics for railway track formation application?

• Railway Loading are different
• Cyclic Vibrations Effects
• Traction (mainly Electrical)
• Seismic Effects when train is running
• Impact loading
• Maintenance of track should not be infringed by
  geo-synthetics
• Rehabilitation methods after completion life
  cycle of geo-synthetics

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FORMATION REHABILITATION

• Work is to be done on running traffic condition
• Methods available for formation rehabilitation
  such as
• With aluminium alloy girder, Track dismantling
  method, With manually operated portals, With c.
  c. crib rail clusters (SE Railway Method), With
  rail clusters (Eastern Railway Method), Lifting
  of track with deep screening, Fully mechanized
  methods.
• Above methods are tedious in operation,
  alternative method need to be explored.
• Railway is interested in develop cost effective
  easy to lay geo-synthetics.

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• HISTORY OF GEO-SYNTHETICS TRIED IN IR
• First time Geo-textiles were tried in Sothern
  Railway (Madras - Gudur section, RDSOs report
  no.C-261, July, 83) for prevention of Mud pumping
  under ballast.
• Geotextile were tried over 12 no. of different
  sites all over Indian Railways in 80s and a
  compilation report State of the Art Use of
  Geotextile in Railways, Nov. 89 was prepared by
  RDSO giving recommended specification of
  geo-textile for track formation.
• Trials of geo-jute along with blanket layer have
  been done in Eastern Railway but not added
  strength to blanket layer. Geo-jute can improve
  only drainage properties.
• Geo-grid was tried in Cuttack Paradeep section
  for track construction over soft soil and design
  of geo-grid reinforced embankment, retaining wall
  and on bridge approach in Jammu-Udhampur section,
  N .Rly (RDSO Report no. GE-13 14, May.1997.
  

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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) for formation rehabilitation.
• Field observations on SCR NR indicate
  improvement in overall track performance after
  the application of geogrid.

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Geo-grid Geotextile on IR

• NF Railway has 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 is satisfactory.
• For low density routes, geotextile along with
  sand layer and brick soling has been used in
  Sitamarhi Darbangha project, ECR.

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CURRENT PROCETS WITH GEO- SYNTHETICS

• Issues involved
• Aperture size of Bi-axial geogrid
• Junction strength
• Material type

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WORLD RAILWAY PRACTICE ON USE OF GEO-SYNTHETICS

• Geo-synthetics being used on many world
  railways.
• American Railways
• Use of geo-synthetics is on experimental basis
  and specific to the nature of problem.
  Specification of geo-synthetics is in draft
  stage.
• Australian Railways
• specify use of geotextile and Geogrid for
  reconditioning/ rehabilitation of existing track
  (Draft guideline).
• UIC European Railways
• UIC consist of different railways. Their loading
  conditions are different for different railways
  and based on the soil type. It is recommendatory
  in nature

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CURRENT PROCETS of GEO- SYNTHETICS

• Railway Budget Speech (2010-11) lay emphasis on
  use of Jute-geo-textile is to enhanced for
  formation rehabilitation under track.(Rehabilitati
  on)
• Project with IIT/Kharagpur for improving tensile
  strength of jute-geotextile with synthetic
  polymers
• Project with IIT/Delhi to study behavior of
  different Geo-synthetics to be used in Railway
  Formationsvalidation through Lab model, FEM
  model site measurements

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Recent Documentation on Geo-synthetics in IR

• Draft Guidelines for use of Geo-synthetics on
  Indian Railways has been prepared by RDSO
  provisional specifications of various
  geosynthetics items based on relevant literature
  survey
• Extended field trials on geogrid are being done
  on IR to validate assess the specifications of
  geogrid.

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FOR INDUSTRY

• Geo-synthetics can find its use in railway
  application for
• track bed stabilization,
• track drainage, erosion control, interface
  protection, construction over soft soil,
• steep slope construction, mud pumping, etc.
• There is need to develop cost effective easy to
  lay geo-synthetics for application in
  construction of new formations rehabilitation
  of existing formations for running of heavy axle
  loads and high speed trains.
• IR look forward active participation of industry
  in this sector.

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THANKS