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

RDSO Research Design & Standard OrganizationOnly R & D organization of IRDeals from Track formation to Bridges to Coaches to signal to OHEMade specifications of products for Railway UseLatest Achievements includesAC Double Decker Coach 4500 HP Hotel load locomotiveVideo Surveillances for running trainDesigning of Track including formation for HAL

Geotechnical Directorate

Deals with R & D of soil mechanics for the use of Railways in

FormationsCuttingsGround improvement RE wall constructions ( ROB )

IntroductionGeosynthetics :Generally Polymer based - Polypropylene, Polyester, PVC, Polyamide, PolyethyleneVarious types of Geosynthetics can be used in Railways

GeotextilesGeogridsGeonetsGeocellGeomembranesGeocompositesPrefabricated Vertical Drains (Band Drains)

Functions of GeosyntheticsGeo-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:

SeparationFiltrationDrainageReinforcementBarrierBasal Layer

Functions of Geosynthetics

Separation

Filtration

Functions of Geosynthetics

Reinforcement

Drainage

Functions of Geosynthetics

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-SyntheticsExisting 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/RUBRoad 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 Geogrids for Erosion Control of Natural Existing Slopes

Construction of RE Embankment

*Typical Cross Section of Embankment with Prefabricated Vertical Band DrainsSand BlanketInitial EmbankmentSoft Clay LayerBand drainsFirm 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

LocationsSpecification requirementFormationsTo be designed for Rly LoadingsCuttingsNo issue with RlysGround improvement No issue with RlysRE 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

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

Specifications and scope for use of geo-synthetics in World Railways American Railways AREMA Manual Part 10

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

Existing Track For Formation Rehabilitation

Specifications and scope for use of geo-synthetics in World Railways Australian Railways Reconditioning Guidelines RTS3430

Existing Track Geotextiles and Geogrids for Formation Rehabilitation

Specifications and scope for use of geo-syntheticsIndian 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 IRGeo JuteAll properties is to be checked with IS codes

PropertiesTest Method (IS)Weight (gsm)IS: 2387Maximum length & widthIS: 1954Ends/dm & picks/dm IS: 1963Thickness IS: 7702Aperture sizeIS: 2405Minimum Breaking LoadIS:1969Maximum Elongation at BreakIS: 1969

Use of IS of geo-synthetics by IRGeo GridAll properties is to be checked with IS codes

PropertiesTest Method (IS)Mass per unit areaIS: 14716Ultimate Tensile StrengthIS: 13162 (Part V)Load at 2% & 5% strainIS: 13162(Part V)Strain at Ultimate Tensile Strength IS: 13162(Part V)

Use of IS of geo-synthetics by IRGeo TextilesAll properties is to be checked with IS codes

PropertiesTest Method (IS)Mass per unit areaIS: 14716Tensile StrengthIS 13162 Elongation at breakIS: 13162Apparent opening sizeIS: 14294Water flow rate normal to the planeIS: 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 IR

Geo-grid+Geo-textile on IRNF 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-gridsField 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-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

ItemPropertyTest MethodValues1Material of Geo-gridAny 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.2Aperture 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.3Roll widthAs per requirement of width attachment to fit with BCM, in the range 3.8m to 4.0m.4Roll length50 m (Minimum)

Mechanical Properties & other Tests

ItemPropertyTest MethodValues

5.1Ultimate Tensile Strength(MD & CD)IS: 13162 part 5 & IS: 13325/ASTM D 6637/BS EN ISO: 10319Two types20 kN/m (minimum)30 kN/m (minimum)5.2Strain at Ultimate TensileStrength(MD & CD)IS: 13162 part 5 & IS: 13325/ASTM D 6637/BS EN ISO: 103198-5% (Range)5.3Junction Efficiency (CD & MD) (Non Essential Test)GRI-GG2-87 and GRI-GG1-87Desirable 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.6.1Radial stiffness at low strain(@0.5% strain)(Non Essential Test)ISO 10319: 1996

ItemPropertyTest MethodValues6.5Resistance to chemical degradation(Non Essential Test)EPA 90906.6aResistance to UV Light Weathering(Non Essential Test)ASTM D43556.6bCarbon Black Test (where applicable as per polymer type material)(Non Essential Test)BS2782 Part-4 Method, 452B: 1993

6.7Creep limited Strength for 15 years period at 30 C temp.(MD & CD)(Non Essential Test)ASTM D 5262/ASTM D6992/ISO 13431

Geotechnical Engg./RDSO*Specification of Non-woven Geo-textile

SLPropertyTest MethodValues1PolymerPolypropylene/ High Density Polyethylene/ polyamide, polyester or similar polymer2Weight/Mass per unit areaIS: 14716 /ASTM D: 3776 300 g/m2 (Minimum)3Thickness of Fabric at 2 Kpa ASTM 51992.0 mm (minimum)4Roll width 5.0 metre (minimum).5Roll Length50 m (minimum)Mechanical Properties1Elongation at break IS: 13162 /ASTM D 4595 /EN ISO: 1031940 % to 70 %2Tensile StrengthIS: 13162 / ASTM D 4595 /EN ISO: 1031915 kN/m (minimum)Hydraulic Properties1Apparent opening size O95IS: 14294 / ASTM D 4751 /EN ISO: 1295640 to 85 microns 2Water Flow Rate Normal to the PlaneIS 14324 / ASTM D 449120 lit. /m2/s (minimum)

Geotechnical Engg./RDSO

Geotechnical Engg./RDSO*Specification of woven geo-textile

SLPropertyTest MethodValues1PolymerPolypropylene/ High Density Polyethylene/ polyamide/ polyester or similar polymer2Mass per unit areaIS: 14716 /ASTM D: 3776240 g/m2 (Minimum)3Thickness at 2 KpaASTM: 5199 0.65 mm (minimum)4Roll width5.0 metre (minimum)5Roll Length50 m (minimum)Mechanical Properties1 Tensile Strength WarpIS: 1969 /ASTM D 4595 /EN ISO: 1031940kN/m (Minimum)Weft35kN/m (Minimum)2Elongation at Maximum LoadWarpIS: 1969 /ASTM D 4595 /EN ISO: 1031915%-30 % Weft15%-30 % 3Puncture StrengthIS: 13162 /ASTM D: 4833600 N (Minimum)Hydraulic Properties1Apparent opening size O95IS 14294 /ASTM D: 4751 /EN ISO: 12956425 microns (maximum)2Water Flow Rate Normal To The PlaneIS: 14324/ASTM D: 449115 lit. /m2/s (minimum)

Geotechnical Engg./RDSO

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 IssuesSpecification- 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 concernTesting 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

THANKS

Other Use Of Geosyntheticis in IRDifferent 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 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.

CONCLUSIONSGeo-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 ConstructionsTo 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.

Geotechnical Engg./RDSO*Specification of Geo-grid

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.

SNPropertyTest MethodValues1PolymerPolypropylene/Polyester or similar polymer 2.Mass per unit areaIS: 14716 /ASTM D: 3776320 g/m2(minimum)3.Aperture sizeSquare 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 widthAs per site requirement and width attachment to BCM 5.Roll Length50 m (minimum)Mechanical Properties1.Ultimate Tensile Strength (MD)IS: 13162 part 5 & IS: 13325 /ASTM D 6637 /BS EN ISO: 1031930 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 1343115 kN/m (minimum)

Geotechnical Engg./RDSO

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