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  • 1. 1
  • 2.  Geotextiles- more aptly Geosynthetics – belong to the class of Technical Textiles under GEOTECH category.  Geotextiles are generically of two varieties—one variety is made of synthetic polymers (petrochemical derivatives) and the other of natural fibres (such as jute, coir)  Geotextiles are intended to improve engineering performance of soil on or in which it is laid 2
  • 3. Jute Geotextiles  Jute Geotextiles (JGT)-as the name suggests –is made of bast fibres of jute plants—a renewable agri-resource under cultivation in the Ganga-Brahmaputra delta for centuries. Presently under cultivation in other areas/countries as well  The British were the first to discover the potential of jute fibre for flexible packaging (sacks) after elaborate tests  The features of jute fibre conform to technical requirements of geotextiles, besides its added advantage of being eco- concordant, abundant availability, and industry-expertise to make customized JGT 3
  • 4.  High moisture absorbing capacity  Excellent drapability (the best of all GTs)  High modulus of elasticity  Low extension-at-break  High roughness co-efficient  Excellent spinnability  Bio-degradability with mulching & soil-nourishing properties  Annually renewable resource with abundant availability  Economical &  Eco-friendly 4
  • 5. JGT matches its man-made counterpart in the three basic functions of a geo textile. They are Separation, Filtration, Drainage. Besides,  Along-plane drainage capability (i.e. transmissivity ) of JGT is higher than its man- made counterpart.  Fineness of jute fiber enables manufacture of JGT according to the specified porometric features  High Roughness Co-efficient of jute ensures better load transference & confining action on soil  JGT has far greater water absorbency than all other GTs –a quality which enables sustained release of the absorbed water, thus creating a congenial micro-climate for better growth of vegetation JGT – Basic Functions 5
  • 6.  Strengthening of road by improving CBR  Slope management  Protection of river bank against erosion  Stabilizing embankments  Prevention of railway track settlement  Consolidation of soft soil  Control of surface soil detachment 6
  • 7. Slope Management with JGT Roads built on high embankments and slopes at construction sites require preventive measures to control erosion of slope surface. Slopes erode due to:  Detachment of top soil by K E of rain drops  Flow of rain water (surface run-off)  Severe wind Surface soil erosion can be controlled by reducing the velocity of surface run-off & entrapping detached soil particles. Wind-induced soil erosion can be controlled by suitable JGT- cover 7
  • 8. Remedial Concept •Universal Hydrological Equation in its simplest form states precipitation  surface flow + through flow ( sub-surface flow ) + storage. •If through-flow and on-land storage can be increased, surface run- off gets reduced. •Through-flow depends on hydraulic conductivity of the soil. Storage can be facilitated by creating micro-barriers on the slope. Such micro-barriers also decrease the velocity of surface flow. •JGT is the ideal material that fulfills the requirements, besides facilitating fast growth of vegetation on its bio-degradation as a result of its mulching properties and by increasing the hydraulic conductivity of soil. 8
  • 9. Soil Erosion Process on a Slope RAIN - - - -- - -- - XC belt of no erosion FLOW active erosion deposition of sediments D a d bb’ e c’ c material in suspension overland flow 9
  • 10. Direction of laying Jute Geotextile Fixing nail Graded slope Grass plant Toe anchor (150 mm x 150mm) 150 Shoulder anchor (150 mm x 150mm) 150 mm 50 mm Fixing nail (II Gauge wire) + 10
  • 11. Role of JGT in Filter-cake formation in soil FILTER CAKE FORMATION IN SOIL IS AN OPTIMAL STATE OF SOIL CONSOLIDATION TRIGGERING GRADUAL DEVELOPMENT OF EFFECTIVE STRESS WITHIN A SOIL MASS, THUS ENABLING IT TO BEAR GREATER LOAD. 11
  • 12.  The surface vegetation prevents the direct impact of water droplets to the surface of soil.  Leafs of the large trees stores rain water for some time and after wetting a large surface area, a reduced amount of water is getting to the soil surface.  Stems and shoots roughen and loosen the ground to enable water to infiltrate more easily. Finally it reinforces the slope by binding the loose soil with it’s root network 12
  • 13. Durability of JGT  Loss of strength of JGT after a year is NOT a drawback – for, 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  With the passage of time dependence on JGT for soil stability continues to decrease However there is need to ensure JGT-durability ranging from 2 to 4 years (depending on the application-type) by special treatment. Eco-friendly durability treatments have been developed by IIT, KgP & IJIRA 13
  • 14.  The answer is NO. Optimal consolidation (development of effective stress) is seen to take place within the effective life of JGT N.B. Effective life of JGT may be enhanced by specially developed eco-friendly water-repellent treatment (developed by IIT Kgp & IJIRA  Necessity of JGT or, for that matter, of any GT ceases after filter-cake formation.  Bio-degradability of JGT is thus not a technical disadvantage. Additionally JGT lends environmental advantage to the construction 14
  • 15. Some Photographs showing application of JGT for Stabilization of Slope 15
  • 16. . LAYING OF JUTE GEOTEXTILE ON AN EMBAKMENT Fig 1 Fig 2 16
  • 17. SLOPE COVERED WITH VEGETATION LAYING OF JUTE GEOTEXTILE AFTER DRESSING OF SLOPE HILL SLOPE GUWAHATI- SHILLONG ROAD AT SONAPUR Fig 3 Fig 4 17
  • 18. Fig 7. Leveling of the damaged road with earth Fig 5. Condition of Damaged Road Fig 8.Finished road after 7 years of construction Fig 6. Laying of JGT over sand 18
  • 19. BRIDGE APPROACH ON R.MUNDESHWARI, West Bengal SLOPE COVERED WITH VEGETATION ON THE SLOPE NEAR A BRIDGE Fig 9 Fig 10 19
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