Coastal & Waterways

Coastal & Waterways

Terram Geosynthetics are commonly used in many coastal and waterway applications such as:
Foreshores, dams and flood bunds, river and canal banks, lagoon, lake and reservoir shores, culverts and outfalls, ports, breakwaters, artificial islands and causeways. 

Geotextile filters in Marine Breakwaters

Application Function

Protection | Filter separators

Market Sectors

Coastal & waterways

Traditionally, marine revetment underlayers have comprised multiple filter layers of stone: grading down from largest stone at the surface. The stone sizes and the number of layers were dictated by the particle size distribution of the underlying soil.

Modern construction techniques utilise a single carefully-selected geotextile layer, to provide the necessary hydraulic and mechanical properties and to prevent leaching of the underlying soil. This geotextile is faster and easier to install than stone layers, and its factory-controlled properties means that it will perform more consistently.

In the same way as the stone size and grading were important for the traditional solution, the careful selection and specification of the correct geotextile is vital. The textile must be robust enough to withstand installation and service-life
loads. It must have a suitable pore size and permeability, and be capable of providing sustained filtration. It must possess extensibility to adapt to point loads in order to avoid puncture
and tearing. Not all geotextiles can provide this unique combination of performance properties.

The role of geotextiles in the provision of stability of hydraulic marine defence structures is vital and often undervalued. This is possibly due to the geotextiles low unit cost in comparison with the overlying armourstone. However, incorrect selection and specification of geotextiles for coastal and waterway applications could risk the stability of the entire structure. When correctly specified and installed, marine geotextiles can provide significant benefits including savings in construction and whole life costs and increase in design life.

Key Advantages:

• Robust Geotextiles can replace graded stone underlays, providing savings in materials, material transportation and placement costs.

• Robust Geotextiles minimise the amount of lost material into soft subsoil at the toe.

• Robust Geotextiles mitigate differential settlement.

 

 

 

 

 

 

The key attributes that require consideration when selecting and specifying a geotextile to be used in revetment type structures are:

Survivability

The geotextile must be robust enough during installation and in service so puncture resistance is very important.

Mechanical performance

The geotextile must have sufficient extensibility to wrap around point loads and avoid puncture and resist compression.

Hydraulic performance

The geotextile must allow water to pass effectively in both directions yet filter fine soil particles.

Durability

Depending on planned exposure times and required design life UV and antoxidant stabilisation will need to be considered..

 

 


Downloads

TERRAM Robust geotextiles