What is the key feature of a trench box?

A trench box is primarily designed to provide safety and support for workers who are operating in trenches during excavation projects. Its main function is to prevent soil collapse, thus creating a secure working environment. By providing structural support, a trench box enhances worker safety by protecting them from potential hazards associated with trench cave-ins.

While it may relate to other aspects of excavation and construction, such as drainage or grading, those are not its primary functions. Similarly, although trench boxes are a form of shoring, they are not used exclusively for this purpose. The key emphasis is on the safety and support aspect, which is crucial in maintaining a safe worksite during excavation activities.