Benching, Battering and Shoring

To watch the video go to "Benching, Battering and Shoring"

Here in Australia the deepest excavation that a person can enter is 1.5m deep.

This height is set so that if a collapse was to occur you would not be buried any further than you waist. This is to try and eliminate a condition called Compressive Asphyxia, this is where the expansion of the lung is limited due to the weight of material on the chest of the victim.

If the excavation that you are getting into is deeper than 1.5m there is a couple of things that should be done before you bet in.

Benching

The excavation is cut in a series of steps. Each step should not be deeper than 1.5m and it should be set back enough so that if the top level was to collapse it would not fall into the bottom of the trench. This method requires a lot more material to be excavated however no shoring is required.

Battering

The sides of the excavation is sloped at the Angle of Repose so that the sides are self supporting. Again,this method requires a lot more material to be excavated however no shoring is required.

Benching and Battering

A combination of the above methods.

Shoring

Shoring is the act of physically holding up the sides of the trench to prevent it from collapsing. There are numerous methods of shoring, both permanent and temporary. A couple of temporary techniques are the shoring box and Sheet piling.