Applications of Jute Geo –Textiles

1. Applications ofJute Geo –Textiles - A presentation by The Jute Manufactures Development Council

2. What are geo-textiles? • Technical textiles that improve engineering performance of the soil • Either made of synthetic polymers (petrochemical derivatives) or of natural fibres (jute, coir)

3. Jute hessian was applied successfully on Strand Road at Kolkata as early as in 1934 and in Myanmar during the 2nd World War First concerted effort to promote use of Jute Geotextile took off in 1980s JGT - the forerunner of man made GT Use of jute for solving soil-related problems is not a new concept. JMDC has published a manual on application of JGT in Civil engineering

4. USP of jute • High moisture absorbing capacity • Excellent drapability (the best of all GTs) • High initial tensile strength • Low extension at break • High roughness co-efficient • High spinnability • Bio-degradable; soil nourisher • Renewable resource, easily available • Economical • Eco-friendly

5. JGT – Basic functions • Separation • Filtration • Drainage • Initial reinforcement. Additionally, it helps in providing biotechnical support to the soil.

6. Separation • Segregates two layers, preventing intermixing • Facilitator to natural consolidation of soil

7. Filtration • Two contrasting functions - • soil retention • allowing pore-water through and along the fabric • Addressing 2 related phenomena – • clogging • blocking.

8. Drainage • Acts as a drain within its own thickness. • Permittivity and Transmittivity of JGT are high

9. Initial Reinforcement • Acts against rotational slides, lateral dispersion and vertical subsidence • Exerts confining action on soil • Partially absorbs effective stress, preventing shear failure.

10. Civil engineering applications of JGT • Slope management • Protection of river bank • Strengthening of road • Stabilizing embankments • Prevention of railway track subsidence • Consolidation of soft soil • Control of surface soil detachment

11. 1.Slope management with JGT Slopes erode due to: • Flow of rain water • Severe wind Can be controlled by reducing the velocity of surface run-off.

12. 1.Slope management with JGT Open weave JGT with 3D construction controls slope erosion : • Creates an array of micro-barriers against the overland flow, reducing velocity. • Effects partial storage due to capacity to absorb water • Entraps detached soil particles.

13. 1.Slope management with JGT • Absorbs water upto about 5 times its dry weight • Stores 0.44 litres per sqm on 1: 2 slope • Promotes quick growth of vegetation.

14. 2. Protection of river banks Causes of river bank erosion • Erodable bank soil • Strong current • Large fluctuations in water level • Waves uplift pressure

15. 2. Protection of river banks Granular / fabric Filter should address 5 basic criteria – • Soil-tightness • Prevention of differential over pressure across the filter • Separation of bank-soil from the overlying filter • Strength to withstand installation hazards • Effectiveness during its design life

16. Disadvantages : • No separation between layers • Results in inter-penetration of layers • Reduction in design thickness of layers • Permittivity is impaired 2. Protection of river banks Conventional Granular Filter • Two – layer construction • Inner core and outer layer.

17. 2. Protection of river banks Fabric Filter • JGT, a natural fabric filter, an effective substitute of conventional granular filter. • Can satisfy all the requirements of filter needed for protection of river banks.

18. 2. Protection of river banks Survivability of JGT depends on-- • Careful storage, handling, transportation, laying on level surface • Guard against puncture by falling aggregates • Guard against soil-slurry at the time of laying

19. 2. Protection of river banks Durability : • In unidirectional flow - 2 season cycles are sufficient for filter-cake formation & natural stability • In flow – reversals - with a moderate cycle time, a longer time is needed ( > 4 season – cycles )

20. Problems of conventional practice • Availability of the right filter materials in time. • Control on quality and workmanship. • Time of execution. • Environmental concerns due to quarrying/ mining for filter materials. Thus a need for an economical and effective substitute.

21. 3. JGT in road construction Causes of failure of roads : • Inadequate pavement thickness • Traffic load & intensity • Low bearing capacity of sub grade • Intermixing of sub-base and sub grade • Insufficient drainage of surface and sub-surface water • Leading to “mud pumping” • Permeable wearing course

22. 3. JGT in road construction • How can JGT help? • Enhances the CBR of the sub grade • Prevents intermixing of sub grade and sub-base • Facilitates filtration & drainage in the sub-surface zone

23. 3. JGT in road construction • Guidelines for designing a new road with JGT • CBR to be taken as 1.5 times the control value of CBR. • Woven JGT should be selected in conformity with the average particle size distribution • Provisions of sub-surface drainage should be made with non-woven JGT concurrently.

24. 3. JGT in road construction • Note : • Choice of JGT also depends on the allowable rut depth which is a factor of the level of service expected of a road vis-à-vis the level of its maintenance • Porometry range: 150 to 400 microns Tensile strength: 25 kN/m should serve the purpose [recommended by the CFGG Manual (French).]

25. 4. Stability of embankments • Expansive or compressive soils used as fills in embankments may lead to: • Vertical subsidence • Lateral dispersion • Downslope migration • Rotational slides (slip circle failure)

26. 4. Stability of embankments • Absorbs stress and strain induced due to moving loads on embankments • Soil - JGT friction acts as a medium of transference of the induced stress and strain • JGT can directly reinforce the soil mass in an embankment only during its useful lifespan • Soil is otherwise stabilized due to separation, filtration and drainage effects

27. Basal reinforcement with JGT for anynew embankment is effective JGT can also be used in successive layers of an embankment and may be folded at the fringes for side restraint • PRECAUTION • Prevent ingress of water into an embankment • Drain out entrapped water from an embankment for which JGT encapsulated concealed drains may be constructed

28. 5. Prevention of railway tracksubsidence • Causes of railway track subsidence • Erosion pumping • Intermixing of ballast and subgrade • Entrapped water within embankment • Surficial erosion  erosion of cess width

29. 5. Prevention of railway tracksubsidence • Solution • Use of JGT (woven + non-woven) on subgrade after removal of ballast layer • Use of JGT encapsulated rubble drains within embankment • Reshaping of embankment profile – rebuilding the cess • Protection of slope with open mesh JGT • Vegetation on slope

30. 6. Consolidation of soft soil • Pre-fabricated Vertical Jute Drain (PVJD) • Better substitute of sand - drains • Drains out water by capillary action • Standard prefab vertical jute drains with jute/coir wicks available • Equivalent drain diameter and its zone of influence may be calculated (as per Runesson et al,1977) to determine the drain spacing

31. 7. Control of surface soil detachment JGT also: • Reduces erodability co-efficient of soil • Attenuates extremes of temperature • Protects soil and seeds from direct exposure • Controls dehydration of soil • Allows air and light • Adds nutrients to the soil and acts as mulch on • Biodegradation

32. 7. Control of surface soil detachment Vegetation as bio-engineering support Vegetation • Dissipates KE of rain drops • Is a receptor of moisture • Attenuates wind effects • Reduces velocity of surface run off • Ensures soil attachment with roots • Improves soil – permeability

33. 7. Control of surface soil detachment Choice of vegetation is important • JGT improves micro-climatic conditions • Enhances organic matter levels • Thus an excellent catalyst for quick growth of vegetation

34. Durability of JGT • Loss of strength of JGT after a year is NOT a deterrent– by that time, JGT provides a self-sustaining sub-grade for most soils • The gain in strength of the sub-grade compensates the loss of strength of JGT within the same time frame (ibid & JU 2005) • With the passage of time soil dependence on JGT for stability decreases

35. Is bio-degradability of JGT a technical disadvantage? • Consolidation of soil by JGT takes about a year • Necessity of GT ceases thereafter. • Degradability of JGT after this period is thus an advantage

36. Comparison between JGT &SGT in respect of properties(for woven type) • JGT has a higher C factor than SGT • 0.005 in a slope of 1:1.5 • 0.004 in a slope of 1:3 • Narrow strip tensile strength – • For JGT – 30 kN/m (warp) x 20 kN/m (weft) usually • For SGT – can customise to any strength • Strain at failure for JGT – 7% to 9% (SGT – usually 23%)

37. Comparison between JGT &SGT in respect of properties (for woven type) • Elongation at break for JGT – 11 % to 13 % • JGT has a high initial tangent modulus (comparable to SGT) • JGT has a breaking strength of 33 kN/m (warp) and 28 kN/m (weft) • JGT offers a greater interfacial friction than SGT • JGT has greater transmittivity than SGT • Permittivity of JGT is comparable to that of SGT

38. Comparative costs of JGT with Synthetic Geo-textile • Open mesh JGT – Rs. 9 - 10 per sq.m. Open mesh GeoSynthetic - Rs. 30 per sq.m. • Woven JGT (treated with rot resistant chemical and bitumen - Rs. 40 - 45 per sq.m. Woven GeoSynthetic – Rs. 80 – 90 per sq.m. • Non woven JGT – Rs. 15 - 19 per sq.m. Non woven GeoSynthetic– Rs. 45 -

39. Comparative Estimated Cost( for West Bengal) • Bank protection of rivers with conventional granular filters – Rs.65 – 70 / sq.m. • Bank protection of rivers with JGT and armour overlay – Rs.60 – 65 / sq.m. • New bank protection of rivers with SGT – Rs. 75 / sq.m. • New road construction with GeoSynthetics - Rs. 57 lac / km (Class AA loading, 7 m. wide) • New road construction with JGT – Rs. 55 lac / km (Class AA loading, 7 m. wide)

40. Advantages Of JGT – in summary • Economical • Easily available • Can be tailor made to meet the criteria of retention and permeability. • Precise control on quality and workmanship possible. • Quicker execution time. • More drapability than any other geo-textile. • Provides a sustainable and Eco-compatible solution. • Conducive natural protection against erosion through quick growth of vegetation cover.

41. New Areas of Research • Use of JGT in asphaltic overlay for prevention of reflection cracks. • Developing a paving fabric as a substitute of masticasphalt. • Turf reinforcing mats with JGT. • Fabriforms • “Jutecrete” • Development of water-resistant & stronger JGT.

42. Standards/Normative References • IS 14986:2001— Guidelines for application of Jute Geo-textiles for rain water erosion control in road & railway embankments and hill slopes • RDSO, Ministry of Railways – • Guideline no GE:G1 (July 2003)— • Guidelines for earthwork in railway projects • Indian Roads Congress— • Specifications for road & bridge works (2001) & • Recommended practice for treatment of embankment slope & erosion control (1991)

43. Case Studies Case Studies in Civil Engineering Case Studies in Agriculture

44. Case Studies In Civil Engineering • Construction of highway embankment on soft marine soil using jute Geo-Textile at Kakinada port – Andhra Pradesh • Widening and strengthening of Munshirhat – Rajpur Road, West Bengal. • Application of JGT for mine-spoil stabilisation in Uttaranchal • Control of bank erosion naturally – a pilot project in Nayachara Island (West Bengal) on the River Hoogly. • Prevention of railway track subsidence with jute Geo-Textile – a case study under Eastern Railway.

45. Project I Name of the project Construction of highway embankment on soft marine soil using jute Geo-Textile at Kakinada Port – Andhra Pradesh Objective Reinforcement of the highway embankment with the help of jute Geo-Textile by minimising post-construction settlement, lateral spreading of fill material etc.

46. Leveling in progress Laying of Jute Geotextile Road before giving final shape

47. Properties of Jute Geo-Textile Used

48. Findings & Conclusion • Water content, void ratio and compression index decreased while dry density and CBR value of the sub-grade soil increased by use of jute Geo-Textile. • Jute Geo-Textile appeared to be very effective even in weak sub-grade soils in reducing their compressibility and increasing their strength as reflected from the good performance even after a lapse of 7 years.

49. Project II Name of the project Widening and strengthening of Munshirhat – Rajpur Road, West Bengal. Objective Strengthening of the widened portion of the existing black top road on both sides with use of jute Geo-Textile for controlling settlement.

50. Consolidation of brick metal laid over JGT on widened portion Widening of Munshirhat – Rajpur Road - JGT is laid on the sub-grade. Finished Road after widening.