Living Reference Work Entry

Encyclopedia of Engineering Geology

Part of the series Encyclopedia of Earth Sciences Series pp 1-4

Date: Latest Version


  • Abdul ShakoorAffiliated withDepartment of Geology, Kent State University Email author 


Densification; Soil stabilization


Compaction or densification is reduction in the volume of voids in a soil mass caused by rearrangement of soil particles by mechanical means.


Compaction is used as a method of stabilizing soils, i.e., improving their properties. Compaction is required when soils are used as a construction material in applications such as structural fill, highway and railroad embankments, earth dams and levees, cover and liner material for sanitary landfills, foundation material, and reclamation of mine waste embankments.

Compaction improves almost all desirable properties of soils. It reduces detrimental settlements, increases soil strength and improves its stability, improves bearing capacity, reduces permeability, and reduces volume changes due to frost action, shrinking, and swelling.

Compaction is measured in terms of dry density (ρd), which is defined as the weight of solids (mineral particles) per unit volume. In the ...

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