Why Use a Geotextile?
To protect against coastal erosion, armor stone revetment are constructed. The energy of the wave action of water is dissipated by the armor stone however as the waves are receding, the water erodes the sandy soil below the armor stones, causing them to displace from their location and eventually damage the revetments structural integrity.
To control soil erosion below armor stone, traditional solution was to make granular soil filter. Soil filter consist of selected sieved and graded granular soil of different sizes place manner to control erosion of base material. With the advent of non-woven fabrics and development of geotextile (filter cloth) , use of geotextile as an alternate material to soil filter has taken impetus as it is easier to install, cost effective and performance is predictable.
Advantages of Geotextile Over Soil Filter
- Placement: Soil filter material is cumbersome and time consuming process. Soil filter placement has limitation as placement of small stones in shallow tidal water. In comparison, geotextile material is easy to install.
- Material Loss: Unlike geotextile material, soil filter material has wastage during transportation handling and placement. When placed over soft sub-soil such as toe of the embankment, rocks buries itself and is lost.
- Differential Settlement: Geotextile sheet like qualities provides stabilization and reinforcement function thereby reducing differential settlement. Soil filter cell placed on soft and loose sandy soil are susceptible to differential settlement that may require regular periodic long term maintenance.
- Cost of construction: Geotextile may cost less than the traditional soil filter cell to control erosion.