North Carolina Building Contractor License Practice Exam

What is the maximum slope allowed for excavation less than 20 feet in total depth in Type C soil?

1. 1:1 slope

2. 3 feet horizontal to 1 foot vertical

3. 4 feet horizontal to 1 foot vertical

4. 2 feet horizontal to 1 foot vertical

The correct answer is: 3 feet horizontal to 1 foot vertical

In Type C soil, which is classified as the least stable soil type, the maximum slope permitted for excavations that are less than 20 feet in total depth is 3 feet horizontal to 1 foot vertical. This means for every 3 horizontal feet of the excavation, the depth can increase by 1 vertical foot, resulting in a slope of approximately 33 degrees. This slope requirement is important for ensuring the safety and stability of excavations. Type C soil tends to have less cohesiveness and higher potential for failure under certain conditions; therefore, stricter slope requirements that are less steep help prevent collapses that can occur with steeper slopes. Understanding these specifications is critical for ensuring compliance with safety regulations and best practices in construction and excavation work, protecting both workers and the surrounding environment.