Coastal & Waterways

Coastal & Waterways

Many coastal and waterway applications commonly use TERRAM Geosynthetics including

Foreshores, dams and flood bunds, river and canal banks, lagoon, lake and reservoir shores, culverts and outfalls, ports, breakwaters, artificial islands and causeways. 

TERRAM Defencell geocells are used for temporary flood protection where a fast response in required and local fill materials are available.

Geotextile filters in Marine Breakwaters

Modern construction techniques for marine revetment underlayers utilise a single, carefully-selected robust geotextile layer, to provide the necessary hydraulic and mechanical properties and to prevent leaching of the underlying soil. 

The role of geotextiles in providing stability of hydraulic marine defence structures is vital and often undervalued. This is possibly due to the relatively low unit cost of the geotextile in comparison to 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.

Geotextiles are faster and easier to install than stone layers, and its factory-controlled manufacturing properties means that it will perform more consistently than traditional construction methods.

TERRAM Robust Geotextiles provide an innovative alternative to traditional materials, but the careful selection and specification of the correct geotextile is vital, in the same way as the stone size and grading were important for the more traditional methods.

The correctly specified geotextile must:

i) be robust enough to withstand installation and service-life loads

ii) have a suitable pore size and permeability, and be capable of providing sustained filtration

iii) possess extensibility to adapt to point loads in order to avoid puncture and tearing

NB: Not all geotextiles can provide this unique combination of performance properties.


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 factors 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..