What Is Embankment in Road Construction?

February 8, 2024

An embankment is a mound of earth or gravel constructed to provide support or protection. Embankments are used in many construction projects, ranging from residential roads to massive highway structures. The construction process and materials of an embankment vary based on the project requirements, site conditions, and available resources. Engineers and construction professionals carefully assess these factors to construct a structurally sound, long-term embankment.

Embankments are designed to resist erosion, support heavy loads, and prevent water accumulation. To protect the soil, engineers build a drainage system into the embankment and install appropriate fill material. To enhance the load-bearing capacity and improve compaction, aggregates like crushed stone or gravel are mixed into the embankment. Geosynthetics, including geotextiles, geomembranes, and geogrids, are also frequently used to reinforce the embankment and improve its durability and performance.

When designing an embankment, form is a major concern. Different soils have varying load-bearing capacities and agreement traits. Choosing the wrong type of fill can cause the embankment to settle unevenly or even fail. Moreover, excess fill can lead to settlement, which requires extensive maintenance and rehabilitation.

Weak or Instable Soil: Construction on unstable soil is a common challenge for road construction. These soils typically have low bearing capacity and high settlement characteristics. These soils are typically soft clays, non-cohesive soils (like sand or gravel), and peat. Oftentimes, the construction of road embankments on these soils is challenging.

To reduce settlement, the construction of road embankments is usually done in layers. Each layer is compacted to the optimum moisture content for maximum dry density, using specified compaction equipment and effort. This can be accomplished through either excavation and fill or piling. In some cases, EPS (expanded polystyrene) geofoam is used to reduce the load on the subsoil and prevent settlement.


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