What is the purpose of compacting soil placed as engineering fill?

The purpose of compacting soil placed as engineering fill primarily revolves around the physical properties of the soil, which include shear strength, compressibility, and permeability. When soil is compacted, its particles are forced closer together, resulting in an increase in density. This denser configuration significantly enhances the shear strength, making the soil more resistant to deformation and failure under applied loads.

Additionally, compacting the soil reduces its compressibility, which is crucial for maintaining structural integrity over time and preventing excessive settlement of the structures built on it. A well-compacted fill will also have controlled permeability, which helps manage water flow through the soil, crucial for preventing excessive water buildup that can weaken the fill material.

While other factors like drainage capacity and vegetation growth are important in soil management and landscaping, they are secondary to the critical engineering analyses of shear strength and compressibility that compaction aims to improve. Therefore, obtaining these properties through compaction is essential for the overall stability and performance of engineering fills.