The construction of embankments for roads, rail and flood defence works often involves the importation and compaction of large quantities of fill material in such a way that the end product is suitable for its intended use.
Indeed, large reclamations by the sea or large rivers can involve the importation, deposition and treatment of many millions of cubic metres of fill material. The source, nature, characteristics, workability and cost of these imported fills can have a major impact on the out-turn cost of a project.
Royal Haskoning has considerable experience of sourcing and selecting fill materials to achieve a balance between cost (including the cost of subsequent compaction or other treatment on site), performance and environmental impact.
Large volumes of imported fill material for embankments, dams and reclamations place considerable additional loads on the foundation soils which could lead to instability of the constructed works or large ongoing settlements over extended periods of time. Royal Haskoning has extensive experience of ground treatment works for improving the characteristics of both the foundation soils and the fill materials to control stability and limit long-term settlements to acceptable levels.
Typical ground treatments can include the use of prefabricated vertical drains to accelerate consolidation soft compressible soils, vibroflotation or dynamic compaction to improve fill materials and avoid the risk of liquefaction or the use of piled foundations in conjunction with geofabrics to support embankments on poor ground.