Which of the following is NOT a purpose of soil compaction?

Soil compaction is a critical process in civil engineering that aims to enhance the performance of soil for construction purposes. Its primary goals include increasing density, improving stability, reducing settlement, increasing shear strength, and enhancing the bearing capacity of the soil.

Reducing settlement is important because properly compacted soil experiences less compression under loads, ensuring that structures placed upon them settle uniformly and predictably. Increasing bearing capacity relates to the ability of the ground to support loads without excessive deformation or failure, which is achieved through the densification of soil particles, creating a stronger foundation. Reducing the void ratio is also a key result of compaction since it translates to a greater density of the soil, minimizing spaces between particles and leading to a more stable material that can better support structures.

In contrast, decreasing shear strength is not a purpose of soil compaction. In fact, compaction typically serves to increase shear strength by removing air gaps and increasing inter-particle contact, which enhances the soil's ability to resist sliding under loads. Therefore, the correct answer to this question is the option associated with decreasing shear strength, as this runs counter to the fundamental objectives of soil compaction.