NICET - Highway Construction Inspection Practice Exam

What occurs when soil moisture content exceeds the optimum moisture content?

1. Soil becomes too dry for compaction

2. Soil becomes excessively compacted

3. Soil is more susceptible to erosion

4. Soil particles become more cohesive

The correct answer is: Soil is more susceptible to erosion

When soil moisture content exceeds the optimum moisture content, the balance of water and soil particles shifts, leading to an increased susceptibility to erosion. At this point, the excess moisture creates a condition where the soil structure may weaken, as too much water can begin to wash away the fine particles, reduce the soil's cohesion, and compromise its stability. In scenarios where the soil is overly saturated, gravity starts pulling down the water, which can result in runoff and soil particles being displaced, particularly in sloped areas. The saturated soil can also become less stable, potentially leading to further erosion issues such as landslides or slumping. This phenomenon highlights the critical role of moisture in maintaining soil strength and integrity. The correlation between moisture content and erosion potential is essential for planning and managing soil in construction and landscaping projects.