Drainage Geocomposites
TERRAPRO™ Drainage Geocomposites create easy-to-install replacements for conventional granular layers. For over 40 years they have established an impressive track record in building and construction projects worldwide, standing the test of time with high-quality performance.
The filter/net/filter composites are used for general area drainage and are easy-to-install, factory-assured replacements for stone installations. The filter/net/membrane composites are used to drain from one side only and provide a barrier to the other – a cut-off drain. Both types can be deployed vertically or horizontally.
The textile provides the filter function, allowing liquids and gases to pass into the net core while preventing soil particles from washing into and clogging the core. The net collects the liquids and gases which can then be conveyed to collection points. Membranes are used to provide the barrier function and prevent the passage of liquids and the majority of gases.
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- Manufactured using TERRAPRO™ TERRAM T1000, a unique geotextile filter developed for its high tensile modulus and ability to prevent soil ingress into the void space of the drainage core
- TERRAPRO TERRAM drainage cores are manufactured from HDPE nets which have been engineered to have good flow under high loading
- Robust to survive installation and service life
- Stable under load to resist deformation that could ultimately restrict flow
- Good chemical resistance
- High-volume flow paths for liquids and gases
- Lightweight and easy to handle, making for easy installation, particularly against vertical faces such as bridge abutment
- Cost-effective replacement for primary natural resources, with factory-assured properties to avoid issues regarding stone grading and consistency
- Reduced environmental impact by avoiding the use of natural-occurring minerals
- Lower haulage costs, lower material
FAQs
A Geocomposite Drain is a thin, three-layer drainage product consisting of two layers of geotextile bonded to a plastic drainage core, which provides a continuous flow path for liquids and gases. The geotextile layers act as filters, retaining soil particles while allowing water to pass through. As a three-layer composite product, it performs the functions of separation, filtration, and drainage.
Terrapro Geocomposite Drains offer several advantages over traditional drainage materials such as drainage aggregates, gravel, and sand, including reduced thickness, ease of installation, consistent drainage performance, and efficient use of space.
Terrapro Geocomposite Drains offer an efficient, economical and environmentally friendly alternative to traditional aggregate drainage layers. They help conserve natural aggregate resources and reduce the number of vehicle movements required during construction. Being lightweight and easy to handle, Geocomposite Drains can be transported, placed, and installed more quickly, enabling faster project execution and reduced construction effort.
Transmissivity (in-plane waterflow) measures the product grade’s ability to convey water under compressive loads, making it the key performance parameter. A high transmissivity ensures efficient long-term drainage even under soil overburden and structural loads. Generally, transmissivity (in-plane water flow) is measured as the quantity of water collected in litters per meter width per second (L/m·s). and load in kilo pascals (kPa).
The filter geotextile must provide the right balance between soil retention through apparent opening size (AOS/O90) and corelated water permeability. Proper selection prevents soil migration and clogging while allowing efficient water flow, ensuring long-term drainage performance and system durability.
Generally, Terrapro 1B1 and 1C1 grades are widely used in the construction industry for vertical drainage applications behind retaining wall fascia and RCC walls, where efficient drainage and water relief are required.
Terrapro 1D1 is commonly used for horizontal drainage applications, particularly beneath railway ballast, to facilitate drainage and minimize water ingress into the railway formation.
Higher-grade Geocomposite Drains may be required where higher water flow rates, greater pressures due to deeper soil fill layers, or lower hydraulic gradients are expected. Grade selection should therefore be based on the required flow capacity, applied pressure, hydraulic gradient, and site-specific drainage conditions.
Terrapro Geocomposite Drains are suitable for a wide range of vertical and horizontal drainage applications to serve various markets, including:
- Retaining walls and reinforced soil walls – relief of hydrostatic pressure behind wall facias.
- Basements and underground structures – drainage and protection of waterproofing systems.
- Bridge abutments and wing walls – collection and conveyance of water away from structures.
- Landfills – leachate drainage and drainage beneath covers/capping systems.
- Tunnels and underground structures – controlled drainage of groundwater and seepage.
- Podium decks and green roofs – drainage and water management beneath landscaped areas.
- Railway formations – horizontal drainage beneath ballast to minimize water intrusion into the formation.
- Roads and pavements – sub-surface drainage and prevention of water accumulation.
- Sports fields and landscaped areas – rapid removal of excess water.
- Plaza decks and roof gardens – drainage and protection of waterproofing membranes.
- Foundations and other below-ground structures – collection and controlled discharge of groundwater.
