Which process involves mechanically forcing soil particles closer together?

Compaction is the process that involves mechanically forcing soil particles closer together, which is essential in civil engineering for the preparation of foundations and other civil works. By applying mechanical energy through methods such as rolling, tamping, or vibration, compaction increases the density of the soil. This process reduces the air voids within the soil structure and enhances its load-bearing capacity, providing a more stable base for structures and reducing issues like settlement and shifting over time.

Consolidation, while related to the improvement of soil strength, involves the gradual reduction of voids due to the application of load over time and the expulsion of water from the soil. Compression typically refers to the application of pressure that may lead to a reduction in volume, but does not specifically address the controlled method of rearranging particles in soil as compaction does. Hardening usually relates to the curing and setting of materials such as concrete or cement, rather than soil particles. Understanding the distinction between these processes is critical for effective soil management in engineering projects.