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

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 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 Road Over Bridge ( 600 ROB constructed per year)

Application In Railway (General) 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 Drains Sand Blanket Initial Embankment Band drains Soft Clay Layer Firm Soil 15 15

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

Geotechnical Directorate Locations Specification requirement Formations To be designed for Rly Loadings Cuttings No issue with Rlys Ground improvement RE wall constructions ( ROB)

Specifications and scope for use of geo-synthetics in World Railways European Railways (UIC) Code 719 R New Construction Geotextiles 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 Construction Geotextiles 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 Construction Geotextiles between Ballast & sub-ballast Geotextiles beneath sub-ballast Erosion 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-synthetics Indian Railways (specific to railway use) Jute geotextiles ( for erosion control) Issued Geo-grids under trial Geotextiles (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 Jute All 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

Use of IS of geo-synthetics by IR Geo Grid All properties is to be checked with IS codes Properties Test Method (IS) 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

Use of IS of geo-synthetics by IR Geo Textiles All properties is to be checked with IS codes Properties Test Method (IS) 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

Geo-grid in IR 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+Geo-textile 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.

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-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 – Rectangular 5. 40-50 mm x 60-65 mm – Rectangular Aperture 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 Tests Item 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 types 20 kN/m (minimum) 30 kN/m (minimum) 5.2 Strain at Ultimate Tensile Strength 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

Item Property Test Method Values 6.5 Resistance to chemical degradation (Non Essential Test) EPA 9090 6.6a Resistance to UV Light Weathering ASTM D4355 6.6b Carbon Black Test (where applicable as per polymer type material) BS2782 Part-4 Method, 452B: 1993 6.7 Creep limited Strength for 15 years period at 30° C temp. (MD & CD) ASTM D 5262/ASTM D6992/ISO 13431

Specification of Non-woven Geo-textile 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 Elongation at break IS: 13162 / ASTM D 4595 / EN ISO: 10319 40 % to 70 % Tensile Strength IS: 13162 / ASTM D 4595 / 15 kN/m (minimum) Hydraulic Properties Apparent opening size O95 IS: 14294 / ASTM D 4751 / EN ISO: 12956 40 to 85 microns Water Flow Rate Normal to the Plane IS 14324 / ASTM D 4491 20 lit. /m2/s (minimum) Geotechnical Engg./RDSO

Specification of 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) Mechanical Properties Tensile Strength Warp IS: 1969 / ASTM D 4595 / EN ISO: 10319 40kN/m (Minimum) Weft 35kN/m (Minimum) Elongation at Maximum Load 15%-30 % Puncture Strength IS: 13162 / ASTM D: 4833 600 N (Minimum) Hydraulic Properties Apparent opening size O95 IS 14294 / ASTM D: 4751 / EN ISO: 12956 425 microns (maximum) Water Flow Rate Normal To The Plane IS: 14324/ ASTM D: 4491 15 lit. /m2/s (minimum) Geotechnical Engg./RDSO

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 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

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

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 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 47

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-Synthetics New 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-grid SN 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) Mechanical Properties 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) Strain at Ultimate Tensile Strength (MD) 8 - 15% Strain at Ultimate Tensile Strength (CD) 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. Geotechnical Engg./RDSO