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The infrastructure that we rely on daily is increasingly under pressure from weather events and associated geohazards. In addition, there is rising demand for development of infrastructure into more challenging ground conditions.
Geosynthetics, such as geotextiles, geogrids, drainage nets, geocells, erosion control blankets and geomembranes are often utilized to meet the design and construction demands of a wide range of projects. These materials are typically readily available, inexpensive and easy to install.
The normal design life of infrastructure project is typically 75 to 100 years. To achieve this design criteria, the designer needs to specify materials which can retain their required design properties over time to meet the project objectives. Geosynthetic are engineered to survive the environment in which they are installed. These products are manufactured from plastics such as polypropylene, polyethylene and polyester which are recognized for their durability and ability to continue to perform under very aggressive environments.
Resiliency is the ability to endure and/or recover quickly after an event. Infrastructure projects are at risk from extreme events such as floods, earthquakes and landslides, which can test our ability to predict loads and resistances under these conditions.
Geosynthetics enhances the behavior of the material they are installed in, such as the backfill materials. In reinforcement applications they will add tensile resistance and confinement of the fill material which improves its response to loads. In drainage and filtration applications, geotextiles allow water to pass while preventing soil particle transport.
This capability is important, as it helps retain soil strength, reduces internal erosion of soil, and minimizes pore pressure build-up. Inclusion of geosynthetics plays a key role in design and construction of resilient structures.
Sustainability or minimizing impact on the environment is an important consideration in infrastructure development. Geosynthetics can support the concept of sustainability by directly reducing the impact of project components with high environmental costs. This is most often realized by utilizing geosynthetics to reduce the volume of excavation, hauling, and use of imported materials.
Geosynthetics in pavement applications can be used to design thinner sections which results in reducing material use and construction cost while improving performance. In embankment construction, they allow for steeper reinforced slopes which reduces the overall footprint and volume of fill material needed. Both examples also reduce the required extent of excavation which can minimize hauling cost in and out of the project. This reduction in materials and earthwork effort is particularly important in remote areas, where transporting aggregates or disposing of excavated soil can significantly increase a project’s carbon footprint.
The use of geosynthetics provides significant advantages in delivering infrastructure that is resilient and sustainable while improving constructability, schedule and cost. They are indispensable materials in the development of modern infrastructure projects. Geosynthetic use will continue to increase as weather related geohazards continue and ideal construction sites become scarcer.
Daniel E. Alzamora, P.E., is a contributing editor for Geosynthetics and has spent more than three decades in the geosynthetics industry in both the public and private sector.