How does erosion control mat function?

Geosynthetic erosion control mats help nature to establish a natural, vegetation cover, as it :

• acts as an artificial root-system
• holds soil particles and seeds
• reduces water and wind velocities
• creates a micro-climate and favours germination of seeds and growth
• reinforces the vegetation cover in the root-zone

Multifunctional geogrids

• grid embedded in nonwoven filter layers
• One-step easy installation
• Optimal interaction with the sub-grade
• High modulus, low strain (Enkagrid TRC)
• Geogrid and nonwoven geotextile together

Functions:
Stabilization+ Filtration+ Separation

What is a PVD ?

• Prefabricated Vertical Drain - PVD
• Also called as wickdrain.
• Used for soil consolidation, settlement instead of sand drains.
• Typically 95 -100 mm wide by 3 - 5 mm thick
• Synthetic core wrapped with geotextile
• The core may be produced from different polymers (PVC, PP, PE or mixtures ...)
• The geotextile jacket type can differ depending on the producer.
• There are also many core types in the market.

Steel water storage silo / tank

Another usage of geosynthetics materials are in steel water reservoirs.

These are very practical and easy to use water storage systems.

They come with all the parts inside and you construct it on site.

Their heights are upto 4.64 meters and diameters vary from 1.85 to 30.95 meters.

Inside the steel construction there is a nonwoven geotextile liner to protect the waterproof tank liner. The tank liner can be made of PVC or other type of polymers depending on the usage.

Capping system for waste areas

Instead of using traditional (mineral) products if we use geosynthetics materials for the capping of waste disposal areas we may have extra storage. So, to use geosynthetics has economic advantages against the traditional products. Also it is more easy to use geosynthetics (geotextiles, geomembranes, geogrids, geocomposites, geomats).

On the picture above you can see a simple comparison of “traditional” mineral- and “geosynthetic” capping of landfills.

As seen the mineral seal and drainage section have much thickness than the geosynthetics drainage and geomembrane seals.

Geocomposite drainage materials are used both for gas and water drainage.

3D-Mat for erosion control

As seen on the picture above 3D mat is a three dimensional, structured, olive green (darker than the picture, you can see the speedlight lights) erosion control mat manufactured from polypropylene monofilaments.

It is easy the installation slopes upto 60 degrees. Covered with soil after seeding. Provides instant protection against soil erosion due to wind, rain, and flash flooding. Creates an artificial root system. Helps nature.

These type of erosion control products can be used for erosion protection of steep slopes, embankments, riverbanks, lakesides, shorelines, spillways, canals, and ditches. Also highly effective on golf courses and residential lawn areas.

Rain water spray absorbing matting for vehicles

Another use of synthetics 3 dimensional mats.

ExSpray is a rain water spray absorbing matting at the inside of mud flaps of trucks and busses. The open structure of the matting "catches" 80% of the rain drops, before spraying out adjacent to the truck. Consequently the rain water spraying effect of the tires is minimized significantly. This results in good view for the cars driving adjacent to the truck or bus.

Waste disposal area

This pictures shows layers of a typical waste disposal area.

• Clay base
• Drain pipes
• drainage layer
• sump pump
• membrane (geomembrane) liner
• leachate collection
• waste
• levelling layer
• filter layers
• gas vent
• seepage drain
• membrane liners (top)
• drainage layer (top)

Some detailled information about waste capping will be sent in next posts.

Calculation of Prefabricated wick drains 1

VERTICAL DRAINAGE DESIGNS
An assessment of the effect of vertical drains on the consolidation process may be made using the method proposed by Kjellman.
This method is based on the assumption that the drains are placed in a regular pattern and that each drain serves a cylindrical soil column of exactly the same length as the drain (colbonddrain) . it is assumed that the increase in vertical load is evenly distributed over the consolidation area and that horizontal layers remain horizontal throughout the consolidation process. It is been assumed
that the permeability of the cohesive soil remains unchanged throughout the consolidation period and that the internal resistance of the drain is negligible. Practical experiments have shown that although these assumptions are not always applicable, in majority of cases their influence on the ultimate results is of little significance. The exception is where drains without a "high flow" core are used for thick highly compressible strata. In such cases the internal resistance of the drain can have a substantial effect on the consolidation period.

How can we control erosion?

In nature it often takes thousands of years till erosion has stopped and a gradual building up of a natural, vegetal cover has taken place.
Mankind can make artificial protection with concrete, stone, wood, etc. or help nature to establish a natural cover.

Also it is possible to use prefabricated plastic erosion control products. Three-dimensional erosion control mattings, made of polyamide monofilaments welded together where they cross, with an open space of over 95%.

Erosion control with honeycomb structures

Honeycomb structured erosion control products has been specially designed for use on sub-bases which do not generally allow the growth of vegetation due to their geological properties. Slag heaps and rocky slopes are examples of this kind of sub-base, upon which a 10 cm thick layer of soil can be applied into the product to form the basis for the development of vegetation.
In such cases, the honeycomb structure allows the mat to be filled with topsoil, providing a lasting grip in the cascading geocells. A further major applications are slopes where the topsoil would erode, if no corresponding measures were taken to combat erosion.
These flexible geocell products are generally made of geotextile fabrics connected to each other reciprocally to form a hexagonal honeycomb structure. The resulting cells can be filled with fertile topsoil, sand, flint or gravel, depending on the specific application. The factors of rigidity and permeability are decisive criteria in the selection of the geotextile fabric used for the production. They are taken into account to ensure that the finished product can ideally fulfil the requirements of its specific application.
The number of anchoring pins of is determined by a great variety of parameters
In addition to its functional characteristics, one of the benefits is its high degree of flexibility. The geocells can follow the gradient of the slope without buckling or warping. Furthermore, the lightweight material allows quick and easy installation. The geocells are resistant to rotting and therefore stabilize the covered surfaces permanently, independent of the vegetation that has been chosen.

Reinforcement of silo foundation

The project contains the foundation of 4 silos with a diameter of 27 m each, to be used for the storage of grain. The soil had insufficient bearing capacity to prevent differential settlements under the circular loaded area.
The steel wall of the silo was placed upon a concrete foundation. The bottom of the silo consists of a circular concrete plate which is not connected to the surrounding foundation of the wall.
When the silo is filled, this could bring about some movement of the plate caused by the consolidation of the subgrade. A local designer made a design with four layers of Enkagrid TRC-20 geogrid to improve the bearing capacity of the foundation underneath the silos.
TRC-Grid reinforces the granular fill and prevents mixing of the particles of the subgrade and the granular fill during the design life.
Furthermore TRC-Grid acts as a filter around the drainage pipe. Differential settlements can occur due to consolidation or loss of bearing capacity of the underlying subsoil between the silo wall and the silo bottom plate. However, the support and the movement of the silo bottom plate should be uniform.

Green slopes with wire mesh and Enkamat

Enkamat and wiremesh hold soil particals, stones and seeds. The Enkamat functions as a griplayer for hydroseeding.

First Enkamat is installed on the slope and then on it wiremesh.

As the green of the first hydroseeding does not cover the whole area, a second hydroseeding is needed.

Climbing plants have been planted in the toe of the slope. The last picture is taken one year after installation.

Especially near the roads you may have a green beautiful view.

Geogrid with a filter layer

Kocaeli free zone project has a harbour inside the project. There is a heavy traffic of trucks. To prevent or reduce partial settlements on the roads due to the heavy truck traffic special geogrid was used.

This multifunctional geogrid delivers reinforcement, separation and filtration in one easy-install product for paved roads, parking areas, platforms and building/structure foundations. In the project it reduced the required subbase thickness.

Due to the special manufacturing method Enkagrid TRC has very low elongation properties.

It helps to reduce the partial settlements.

Beside the reinforcing Trc geogrid also provides a filter layer. So it works like a geogrid and a nonwoven .

This type of geogrids work as reinforcement, separation and filtration layers.

Erosion control

Why erosion control

• during the erosion process soil particles are transported, resulting in the gradual deformation and destruction of slopes, banks, shores, rivers bottoms, etc.
• elsewhere, erosion causes undesirable sedimentation on agricultural land and roads, in rivers and drainage systems, etc.

How can we control erosion?

a)Existing slopes:

• prevent removal of the vegetation
• in case of new slopes protect the fertile surface layer by means of:
  -coarse, less erodible surface
  -flatter slopes / terraces
  -surface cover with concrete, stones, plastic sheets
  -temporary plastic sheets over surface in rain season
  -geosynthetic mats
  -biodegradable mats

b)In case of slopes of ditches/channels:

• revetment structure
• concrete blocks

Fountains and water displays

In controlling water movement, back splash, and noise in commercial fountains and water displays you may need a material to reduce the sound. Three dimensional products which can control these , can be used used in theme parks, shopping malls, restaurants, museum exhibits etc.

For more detail :sport & leisure

Geosynthetics

We can simply devide geosynthetics in below groups.

1)Geotextiles:

• Woven fabrics
• Geogrids
• Nonwoven fabrics (Thermally, mechanically, chemically bonded)
• Nets
• three dimensional mats

2)Geomembranes:

• HDPE , LDPE liners

3)Geosynthetics clay liners, (bentonite mats)

4)Geocomposites

Geocomposites are made by using above product with each other. For example a drainage composite can be made by joining 2 filter fabrics (nonwovens) and a 3 dimensional mats in the middle.