Alabama Contractors License Practice Exam

What is the maximum slope limit of safety for permanent fill?

1. 1 to 1

2. 2 to 1

3. 3 to 1

4. 4 to 1

The correct answer is: 2 to 1

The maximum slope limit of safety for permanent fill is typically set at a ratio of 2 to 1. This means that for every two horizontal units, there should be one vertical unit of fill. This ratio is important for ensuring stability and reducing the risk of erosion, sliding, or failure of the fill slope. A 2 to 1 slope provides a safer angle that can help prevent the weight of the fill material from overloading the base and supports, contributing to long-term stability in various conditions, including weather changes and soil saturation. Using steeper slopes (like 1 to 1) may increase the risk of instability, while flatter slopes (3 to 1 or 4 to 1) may not be as efficient in space usage if high fill volumes are necessary. However, safety considerations often take precedence in construction practices, making the 2 to 1 slope a commonly accepted standard for permanent fill areas.