geo-synthetics specifications for railway sector rajesh agarwal, director, rdso

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


Separation

Filtration

Natural Soil

Geo-textile

Water Flow Direction

Granular Soil


Reinforcement

Drainage


Barrier

Scope for use of geosynthetics

Vision 2020

New Lines -- 25000 km route expansion DFC- Western & Eastern CorridorDouble/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 Road Over Bridge ( 600 ROB constructed per year)

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)

Use of Synthetic Use of Synthetic Geogrids for Erosion Geogrids for Erosion

Control of Natural Control of Natural Existing SlopesExisting Slopes

Construction of RE EmbankmentConstruction of RE Embankment

15

Typical Cross Section of Typical Cross Section of Embankment with Prefabricated Embankment with Prefabricated

Vertical Band DrainsVertical 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)

USES OF GEO-GRID

GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION

GEOSYNTHETICS APPLICATION IN RAILWAY FORMATION

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 ConstructionGeotextiles between blanket and prepared subgrade if prepared subgrade has fines more than 15%

Existing Track Geotextiles and geogrids for Formation Rehabilitation


American Railways AREMA Manual Part 10

New ConstructionGeotextiles between Ballast & sub-ballastGeotextiles beneath sub-ballastErosion Control on slopes

Existing Track For Formation Rehabilitation


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) IssuedGeo-grids under trialGeotextiles (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 JuteAll 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


Geo GridAll properties is to be checked with IS codes


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)


Geo TextilesAll properties is to be checked with IS codes


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 IRGeo-grid in IR

Geo-grid+Geo-textile on IRGeo-grid+Geo-textile on IR NF Railway also tried use of Geo-grid (Polyester based – NF Railway also tried use of Geo-grid (Polyester based –

knitted & coated with strength of 40 kN/m & aperture size knitted & coated with strength of 40 kN/m & aperture size of 25mmx25mm) in combination of geo-textile and sand of 25mmx25mm) in combination of geo-textile and sand layer for formation rehabilitation. layer for formation rehabilitation.

The performance report of the trial section of NF Railway The performance report of the trial section of NF Railway

is satisfactory.is satisfactory.

For low density routes, geotextile along with sand layer and brick For low density routes, geotextile along with sand layer and brick soling has been used in Sitamarhi – Darbangha project, ECR.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-gridsGeo-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 – Rectangular5. 40-50 mm x 60-65 mm – RectangularAperture 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 TestsItem 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 types1.20 kN/m (minimum)2.30 kN/m (minimum)

5.2 Strain at Ultimate TensileStrength(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

ItemProperty Test

MethodValues

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./RDSO36

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

2Water Flow Rate Normal to the

PlaneIS 14324 / ASTM D 4491

20 lit. /m2/s (minimum)

Specification of Non-woven Geo-textile


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)


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)

2Water Flow Rate Normal To The

PlaneIS: 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 RiasiBank of 16m to 56 m highDesign 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

Specification- Generic in natureTo avoid monopoly Material to be readily available (Time constraint)

Cost effectiveShould be competitive with AlternatesResearch with Blending of Jute with PP etc.

being explored by Railways

Issues concern

Testing facilitiesContracts to be awarded division wise & to be

passed by divisional authoritiesHow testing of material to be monitored

Works contract/Supply contractRailway 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

THANKSTHANKS

Other Use Of Geosyntheticis in IROther 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 & Formation treatment with blanket & geotextile by formation rehabilitation m/cgeotextile 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 dayGeotextile 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-SyntheticsNew 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.


Specification of Geo-gridSN 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)


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.

geo-synthetics specifications for railway sector rajesh agarwal, director, rdso

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