Name a method to increase the compaction of granular soils.

Using vibratory rollers or tamping equipment is an effective method to increase the compaction of granular soils because these devices apply dynamic loads that enhance the rearrangement of soil particles into a denser configuration. Vibratory rollers work by generating vibrations that cause the soil to compact under its own weight, while tamping equipment provides impact force that compresses the soil particles. This process not only reduces void spaces but also helps achieve optimal moisture content, which is essential for maximum density in granular soils.

In contrast, excessive watering of soil can lead to adverse effects like excessive moisture that may weaken the soil structure, while using only hand tools does not provide the necessary force or vibrations needed for effective compaction. Leaving the soil to settle naturally can result in insufficient compaction, as it relies on gravity alone without employing any mechanical means to densify the soil. Therefore, the use of mechanical equipment specifically designed for compaction is the most effective method for achieving well-compacted granular soils.