Which of the following is a common protective system used in excavation?

Trench boxes are a common protective system used in excavation to safeguard workers from cave-ins and soil collapses. These boxes are designed as strong structures that can be placed in an excavation site to provide a safe working environment. They help stabilize the walls of the trench, preventing soil from shifting and allowing workers to operate safely within the excavation.

The use of trench boxes is particularly critical in deep excavations, where the risk of cave-ins is higher. By ensuring that the excavation site is well-supported, trench boxes significantly reduce the risk of injury or fatality due to unexpected soil movement.

Additionally, they are designed for easy installation and removal, making them efficient and practical. Proper use of trench boxes, alongside other safety measures, contributes to a comprehensive approach to excavation safety, which is essential in construction and other activities that involve digging.