In cup trench construction, where is the berm placed to catch rolling material?

In cup trench construction, where is the berm placed to catch rolling material?

• A. On the outermost downhill side.
• B. On the uphill side.
• C. Across the trench center.
• D. No berm is used in cup trench construction.

Answer: (A)

In cup trench construction, the berm is placed on the downhill outer edge. This setup uses gravity to your advantage: material that loosens or slides on the slope will roll toward and be caught by the berm, preventing it from sliding into or past the trench and helping keep the fireline clean and stable. Placing a berm on the uphill side wouldn’t intercept material that starts to move downhill, and putting it across the trench center wouldn’t stop rolling debris from bypassing the trench. Omitting a berm altogether removes that catch mechanism, increasing the risk of debris causing erosion or undermining the line.

In cup trench construction, the berm is placed on the downhill outer edge. This setup uses gravity to your advantage: material that loosens or slides on the slope will roll toward and be caught by the berm, preventing it from sliding into or past the trench and helping keep the fireline clean and stable. Placing a berm on the uphill side wouldn’t intercept material that starts to move downhill, and putting it across the trench center wouldn’t stop rolling debris from bypassing the trench. Omitting a berm altogether removes that catch mechanism, increasing the risk of debris causing erosion or undermining the line.