Dykes
Dykes are essential structures that protect us from floods. By definition they are built on weak soils which will cause differential settlements. Erosion becomes a risk when water levels are high and dykes are under heavy attack from waves for a period of time. Another risk is the so-called piping phenomenon that may cause serious damage during high water.
Building dykes on weak soils with heavy duty woven reinforcing fabrics is a technology that has existed for 40 years since it was first used along the Mississippi in the USA. In general three failure modes can be identified:
- loss of overall stability
- loss of foundation stability
- bearing capacity failure
Design advice is available on request.
When water levels are high, the resulting pressure can force water to seep through the base of a dyke. This water may take grains of sand with it, creating tubular openings (pipes) under the dyke that get bigger and bigger, jeopardising the stability of the structure. This can weaken the dyke and, in the worst case, cause it to collapse. Vertical screens of Enka-Tex geotextiles are used as filtering layers to avoid piping. The principle of the vertical screen is based on allowing water, but not sand, to pass through the base of the dyke.
Where environmentally friendly engineering is a priority, Enkamat is used for dyke slope sections above the main water level. This allows for erosion protected embankments to grow naturally vegetated facings. Below that level, flexible Enka-Fix with precast concrete blocks or Enka-Mattress have proven to withstand heavy wave attacks.
A large variety of uses for geosynthetics contributes to the stability of embankments during construction and during their lifetime.
Horizontal base layers prevent extremely soft silt layers from being squeezed out and contribute to global stability against sliding and slip circles. By using this method the bearing stability is better controlled during installation.
Functions:
- Reinforcement
- Piping prevention
- Separation
- Filtration
- Erosion protection
Relevant products:
