Fildrain Geocomposite | Earthworks, Slopes & Embankment Drainage

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 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.

Applications

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

Benefits

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.

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: