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RIVER
& CANAL
BANK
PROTECTION |
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Where applicable
Geotextiles can be used as a filter instead of multilayer conventional
mineral filter under permanent armour.
The armour on the filter is boulder, brick block,
concrete slab depending on site conditions. It is very effective for
unidirectional waterways and flush flood areas.
Why applied
Flowing water in a river and canal cuts the soil under bank, which becomes unstable and collapses. Application of geotextile helps to arrest
movement of soil particles by the flowing water and allows the water to pass. The geotextile acts as a filter having a definite pore size to retain the solids and allow liquid. The pore size is determined on the basis of soil particle size and the fabric is designed accordingly. Disadvantages
associated with mineral filter for protection of bank of waterways are
as follows.
 Infiltration of underlying materials, thus impairing separation function
Scour
Difficulty in controlling the quality of construction
Requirement of large quantities of raw materials and their transportation
High cost
Longer time of construction
Difficulty in adopting the method in emergency
The mineral filters are many times thicker than the jute geotextiles by a factor around 100
Product specification
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Type &
Code |
Weight (gsm) |
Width (cm) |
Thickness
(mm) |
Pore size
(micron) |
Strength
(kN/m) |
Elongation
at break (%) |
Water
permeability
(l/sq.m/sec) |
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MD |
CD |
MD |
CD |
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Woven
& Treated
BGW 760 BT |
1200 |
76 |
2.5 |
150 |
25 |
25 |
10 |
10 |
21 |
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Packing – Rolls of 50m each with anti-sticking polyethylene in between layers.
Colour - Black
How to apply
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| 1. |
If stitching at the site is not possible, the cut pieces may be laid on the slope with an over lapping
suggested in the plan below. |
| 2. |
At the bottom, the fabrics may be anchored below a sausage, if it is in the design, otherwise a toe beam of suitable size depending on the river condition may be made of the fabrics. The beam after filling with sand may be placed in the riverbed. |
| 3. |
The treated area should be covered by riprap of suitable material. During construction of the riprap sufficient care should be taken so that the filter fabrics are not damaged any way. |
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4. |
If, damaged,
the portion
may be overlapped by a fresh piece of fabric.
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Installation Plan of Jute Geotextile for River Bank Protection |
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