Final answer:
Trench boxes are filled with backfill to prevent trench wall collapse, which stabilizes the trench walls and protects workers from cave-ins.
Step-by-step explanation:
The question appears to be a mixture of a construction safety topic and details from World War I trench warfare; however, answering the construction safety aspect: When using trench boxes, the space between the box and the trench wall is backfilled to prevent the trench walls from collapsing. Trench boxes are a safety measure implemented to protect workers from cave-ins when working within a trench. The backfill material creates pressure against the trench box, which helps stabilize the trench walls by compacting loose soil and reducing the chances of a trench wall failure. This method prevents potential injuries and ensures the overall stability of the excavation site.
When using trench boxes, the space between the box and trench wall is backfilled for several reasons:
To provide additional support and stability to the trench box. The backfill material acts as a counterbalance, preventing the box from collapsing inward due to the pressure exerted by the surrounding soil.
To prevent soil movement and potential cave-ins. By backfilling the space, the soil is compacted against the trench box, reducing the risk of soil shifting and ensuring a safer work environment.
To increase the overall strength of the trench system. Backfilling helps distribute the load evenly across the box and the surrounding soil, minimizing the chances of structural failure.