NICET - Highway Construction Inspection Practice Exam

What is the effect of using overly wet soil in construction?

1. It provides better stability

2. It enhances load-bearing capacity

3. It increases the risk of erosion

4. It allows for easier excavation

The correct answer is: It increases the risk of erosion

Using overly wet soil in construction primarily increases the risk of erosion. When soil is saturated with water, it loses its cohesion and becomes more susceptible to being washed away by surface runoff or heavy rains. This process can destabilize slopes, foundations, and roadbeds, leading to further complications in construction and potentially endangering the structural integrity of any work already completed. In addition, overly wet soil can contribute to problems such as soil liquefaction during seismic activity, where the soil temporarily loses its strength and behaves like a liquid. This effect makes the risk of erosion even more pronounced, as loose or saturated soil can be easily displaced. While it might seem that wet soil could enhance load-bearing capacity, the opposite is often true. Saturated soils may compress under loads or cause a reduction in effective stress in the soil structure. Proper moisture content is essential for maintaining the stability and strength of soil in construction. The notion that overly wet soil allows for easier excavation is misleading because wet soil can become sticky and difficult to remove, complicating excavation efforts rather than simplifying them. Thus, the primary impact of using overly wet soil in construction is indeed the heightened risk of erosion.