Nikhiel Budhai, Laboratory Manager, WSP in Africa
Geotextile dewatering tubes are usually brought into a project to contain sediment and remove water. Once that immediate function is complete, they are often still considered temporary works. Yet a filled and consolidated tube can behave as a confined-fill structural unit that can be assessed using familiar geotechnical principles.
My research looks at whether this behaviour could give geotextile dewatering tubes a broader role in civil engineering. For suitable applications, there is a case for evaluating them as permanent structural elements alongside more conventional options.
How the tube behaves once it is filled
Once the tube has been filled and consolidated, engineers should assess it as a complete structural system. Its performance depends on the fill inside it, the geotextile containing that fill and the ground it rests on. Those parts influence one another, so the design must consider how the system carries load and how it may deform over time.
That behaviour has parallels with conventional embankments and gravity-type structures. It means engineers can assess these systems using established geotechnical approaches rather than treating them as a separate class of temporary product.
If a geotextile tube is to remain part of a permanent structure, it must be assessed with the same care as any other geotechnical element. Engineers need to understand how it will behave under the loads expected on site, whether the geotextile and its seams can carry the forces created by confinement, and how much movement the structure can accommodate over time.
Designing for long-term use
Durability also should be considered from the start. Abrasion can affect the material over time, as can prolonged exposure to ultraviolet light. The design also needs to account for possible damage from external actions during the structure’s service life. Material selection and detailing therefore need to reflect the conditions the system will face.
Foundation conditions are equally important. Because a filled tube can distribute load over a relatively broad area, it may offer advantages in softer ground where concentrated bearing pressure is difficult to manage. That benefit still should be demonstrated for the conditions of the individual project.
I see geotextile tubes as another option in the engineer’s toolkit. Their suitability should be judged against the required function and site conditions, just as it would be for a more conventional solution.
Where this could be used
The applications range from inland waterways to coastal works. A tube could, for example, form part of a riverbank stabilisation system or provide support at the toe of an embankment. In coastal projects, the same structural behaviour could be used in shoreline protection or in areas exposed to hydraulic forces.
These applications make use of characteristics that can be valuable where construction access is constrained, or some deformation can be accommodated. The modular nature of the systems can also support phased installation.
I came to this research through the waste problem in mining. Large volumes of material can remain in storage for decades, with engineers having to manage the risks that come with it. That led me to consider whether some of that material could be treated and reused in construction, rather than simply remaining in long-term storage.
Geotextile dewatering tubes can contribute to that discussion because they can use locally available or waste-derived fill in appropriate circumstances. This creates scope to reduce demand for conventional materials and support resource-efficient construction, provided the material and the structural system are properly assessed.
Building local confidence
I believe the next step in South Africa is to test the idea properly and build up local experience. There are possible uses in mining-affected areas, rivers, and coastal environments, but there are still relatively few documented large permanent installations here. Pilot projects would give engineers a better sense of how these systems perform under local conditions and help build confidence in where they can be used.
International case studies show that these systems have already been used in structural applications, but that does not remove the need to assess local conditions. Cost will be part of that decision, together with the design requirements and the level of performance expected over the life of the structure.
Perception can also narrow the options before a proper assessment begins. Geotextile tubes have been associated with temporary containment and dewatering for so long that their structural potential may not be considered during early design.
The better approach is to test their feasibility using the same engineering principles applied elsewhere. If the system can satisfy the relevant stability and serviceability requirements, while addressing long-term durability, it has a legitimate place in the design conversation.
There is still work to do in South Africa through research, piloting, and validation. The next step is to assess the technology more widely and identify the projects where its structural behaviour and potential use of recovered material make it a credible option.
Nikhiel Budhai presented research from his paper Structural Applicability of Geotextile Dewatering Tubes: Reframing Confined-Fill Systems for Permanent Civil Infrastructure, co-authored with Ganesh W. Rathod, at the 13th ICG Conference in Montreal in September 2026. WSP in Africa is hiring! To find out more about available opportunities, check out the Careers page on our website or look out for updates on our LinkedIn page, @WSPinAfrica.
