Question

what are the three main protection methods against cave - ins?
select the best option.
shields, shoring, and roofing
shields, shoring, and sloping
frames, shoring, and sloping
if you need to review this content, it can be found in the protecting workers from cave ins and utility hazards module of the excavations topic.

Explanation:

Shielding (using trench boxes), shoring (installing support systems), and sloping (cutting the sides of the excavation at an angle) are standard methods to prevent cave - ins. Roofing is not a main protection method for cave - ins in excavation safety. Frames are not one of the three main recognized methods.

Answer:

Shields, shoring, and sloping