What is the term for the densification of soil through mechanical means?

The term for the densification of soil through mechanical means is compaction. Compaction involves the process of reducing the volume of soil by applying mechanical force, which increases its density and strength. This is commonly achieved through various methods such as rolling, tamping, or vibrating the soil. Compaction is essential in construction and engineering applications to improve soil stability, decrease settlement, and enhance the load-bearing capacity of the ground, which is critical for supporting structures.

In contrast, smoothing refers to the process of leveling or finishing a surface, which does not specifically involve soil densification. A caisson is a type of deep foundation, and centerline typically refers to a central reference point in a design, neither of which relates to the mechanical densification of soil. Thus, compaction is the correct and relevant term for this process.