Trenching

Trenches are defined by OSHA as "a narrow underground excavation that is deeper than it is wide, and no wider than 15 feet." Soil analysis and sampling must be done to adequately prepare for proper trenching.

There are three main ways to prevent cave-ins: sloping the walls, shoring the walls with supports, or shielding the walls with trench boxes:

• Sloping the trench walls requires cutting the trench wall at an angle inclined away from the excavation.
• Shoring trench walls involves using aluminum hydraulic supports, or other approved supports, to support and prevent the soil from moving.
• Shielding involves the use of trench boxes, or similar items. Trench boxes are steel or aluminum structures that are made of outer sidewalls connected by spreaders.

Any trench greater than five feet requires a protective system, and trenches greater than twenty feet require a protective system specifically designed by a registered professional engineer.

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