Typically, shallow excavations are defined as being up to a depth of 1.5 metres. Deep excavations are defined as being deeper than 4.5 metres. Deep excavations are much more difficult to plan than shallow excavations, and they require much more time and resources.
At what depth must an excavation be supported?
Trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is made entirely in stable rock. If less than 5 feet deep, a competent person may determine that a protective system is not required.
What is the 1 2 depth RULE?
All simple slope excavations 20 feet or less in depth shall have a maximum allowable slope of 1½:1. 2. All excavations 20 feet or less in depth which have vertically sided lower portions shall be shielded or supported to a height at least 18 inches above the top of the vertical side.
What is cave in in excavation?
A cave-in occurs when walls of an excavation collapse. Cave-ins can be deadly. Wall failures often occur suddenly, with little or no time for the worker to react. The weight of the soil crushes and twists the body, causing death or serious injury in a matter of minutes.