Which safety measure involves installing support to prevent wall collapse?

• A. Inspect soil
• B. Use shoring or trench boxes
• C. Provide escape routes
• D. Keep loads away

Answer: (B)

Installing support to prevent wall collapse is achieved by using shoring or trench boxes. These systems brace the trench walls, resisting the lateral earth pressure that could push the sides inward and cause a cave-in while workers are inside. Shoring uses uprights and cross braces to hold the soil, while trench boxes are pre-engineered steel structures left in place to provide wall support. This direct wall-support measure is essential in trenches with unstable soil, high groundwater, or deep cuts, where the risk of a cave-in is greatest. Inspecting soil helps evaluate stability and plan protection, but by itself it does not stop a collapse. Providing escape routes is about quick exit in an emergency, not preventing a collapse. Keeping loads away reduces surface pressure near the trench edge without offering wall support.