Fildrain - Earthworks & Embankments

Fildrain drainage geocomposite for civil engineering earthworks and embankment drainage and consolidation

Fildrains’s unique drainage core replaces the requirement for stone filter layers providing superior flow horizontally and vertically. The filter geotextile prevents clogging of the core.

Fildrain - Earthworks & Embankments

Fildrain drainage geocomposite for civil engineering earthworks and embankment consolidation. A cost-effective alternative to traditional stone drainage systems by collecting and channeling water or gases to a suitable drainage point.


  • Embankment starter layers
  • Embankment drainage
  • Combined surface and sub-surface drainage
  • Embankment basal and consolidation layer
  • Embankment counterfort drain


  • Cost effective
  • High water flows compared to traditional drainage stone
  • Re-use of site won excavated material
  • Reduction or elimination of drainage stone
  • Speed up consolidation
  • Rapid installation
  • Allows water flow in all directions
  • Reduction in haulage requirements

Drainage is a major consideration in all civil engineering earthworks, embankment and slope projects. Sub-surface drainage using a Fildrain drainage geocomposite horizontally in place of a granular starter layer, as well as to relieve pore pressure and accelerate consolidation. Sub-surface drainage options have been limited to traditional crushed stone filter drains even though modern materials are available. The modern option of the Fildrain geocomposite enables greater use of site won as-dug materials and this in turn minimises the number of vehicle journeys, both delivering and removing materials from site.

Embankment Starter Layers

A thick granular drainage layer is often placed onto the prepared formation before construction of an embankment. This layer serves two functions, one of which is drainage and the other is to protect the formation from heavy construction machines.
Introducing Fildrain 7DD/ST170 or 7DHD/ST170 will provide the required drainage capacity, this would be overlaid with at least 300mm of fill before tracking with construction plant.

Fildrain geocomposite drainage layer is laid across the width of the embankment and the backfill placed on an advancing face. The geocomposite must have sufficient compressive strength/flow for the forces under the full height of the embankment and ideally have a core with a central barrier that protects the formation from water ingress and re-hydration due to rainfall..

ABG Fildrain Embankment Fin Drain Drainage system

Consolidation Layers

Earthworks are usually on the critical path and the programming of the project works, and on soft soil embankments these are no exception. The speed of construction of the embankment depends on the rate at which the pore water pressure can dissipate as the embankment height progresses. Fildrain geocomposite is so effective at reducing pore pressures, that it significantly increases the range of soils that can be considered as suitable fill. Even very wet soils that would be unsuitable for use with granular drainage layers may be considered usable. Fildrain geocomposite has a central core that is impermeable to restrict vertical movement of water, which means that each layer of Fildrain acts as a roof to the fill below, preventing rainfall from slowing consolidation. Consequently the weather window for earthworks is extended. Using Fildrain instead of crushed stone utilises more fill, which is cost saving and has a positive impact on the earthworks balance.

ABG Fildrain Embankment Drainage system 
ABG Fildrain starter layers

Slope Drainage

Slope drainage is primarily required to collect seepage water emerging from permeable layers in soil slopes, or from open joints in rock slopes. It is there essentially to stop topsoil from slumping or being eroded by water from below.

ABG Fildrain Y Embankment Fin Drain system

When designing and constructing cuttings, the ground water level is reduced below the intended surface of the cutting slopes.  Traditionally this is achieved with crushed stone counterfort drainage trenches.  Installing any trench on a steep slope is not easy.  Fildrain helps to make the process simple, in one of three ways:

  • Fildrain is installed upright in narrow trenches
  • Fildrain is laid flat in strips before the topsoil layer is placed
  • Fildrain is laid across the whole area before the topsoil is placed

In addition to new build, Fildrain is excellent for dealing with seepage that has appeared on the existing cutting slopes.

Case Studies / Recent Projects:

Fildrain drainage geocomposite has been used in the following civil engineering projects:

Related Products

The following similar products provide solutions civil engineering, structural, ground and highways drainage:

New embankment construction project using Fildrain drainage layers
ABG Fildrain Embankment Fin Drain Drainage system

Associated System Products

Within a Fildrain construction, products that may also be considered are:

Typical Client Profile:

  • Drainage Contractors
  • Water companies
  • Covered Reservoir engineers
  • Landscape Architects
  • Structural Engineers

Earthworks and Embankment Starter Layers - Carbon Footprint Saving

The use of ABG's Fildrain Drainage Geocomposite can save up to 57% on the carbon footprint compared with traditional granular starter layer methods:

Click to read the full carbon footprint assessment
Carbon footprint reduction using ABG geosynthetics for soil drainage and Embankment starter layers verses traditional methods

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