Answer: All of the above
Explanation:
Excavation and trenching is the most dangerous types of construction. Shielding helps to provide safety to the employees. It provides protection against cave ins.
The simplest form of protection is benching and shoring. where the walls of the excavation are sloped or benched. The angle to be sloped is determined by the type of soil i.e. how stable it is
Shoring means to provide sideways support to the soil which prevents it to fall off
