Which of the following describes the process of compaction?

The process of compaction is described accurately by the choice that focuses on packing soil to increase its density. During compaction, the objective is to reduce the volume of air voids between soil particles, thereby increasing the overall density of the soil. This is typically achieved through mechanical means such as rollers, plate compactors, or heavy equipment that applies pressure to the soil.

Increasing the density of the soil improves its load-bearing capacity, reduces settlement, and minimizes the potential for soil erosion. Compacted soil is essential in construction and earthwork because it provides a stable foundation that can support structures and withstand external forces.

Other options do not reflect the concept of compaction correctly. Loosening soil to increase aeration would actually serve to decrease density and is counter to the goals of compaction. Excavating soil pertains to the removal of soil, not the process of increasing its density, and measuring soil pH levels is unrelated to physical properties of soil density, focusing instead on chemical characteristics.