geo-synthetics specifications for railway...

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)

� 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

15

Typical Cross Section of Embankment with Prefabricated Vertical 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 Construction � Geotextiles 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 Construction � Geotextiles between Ballast & sub-ballast

� Geotextiles beneath sub-ballast

� Erosion 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) 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


Geo Grid All 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 Textiles All 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 IR

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 1. 20 kN/m

(minimum) 2. 30 kN/m

(minimum)

5.2 Strain at Ultimate Tensile Strength

(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

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

Geotechnical

Engg./RDSO 36

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

2 Water Flow Rate Normal to the Plane

IS 14324 / ASTM D 4491

20 lit. /m2/s (minimum)

Specification of Non-woven Geo-textile

Geotechnical

Engg./RDSO 37

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)

2 Water Flow Rate Normal To The Plane

IS: 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 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

�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

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.

Geotechnical

Engg./RDSO 51

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)


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...

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