Shoring

Shoring systems use hydraulic, pneumatic, or mechanical jacks placed between the walls of an excavation to hold the soil in place and prevent cave-ins. Shoring is one of three OSHA-accepted methods of cave-in protection, along with sloping (cutting the walls back at a safe angle) and shielding (using trench boxes to protect workers). The choice of method depends on soil type, excavation depth, available space, and project requirements.

In hydrovac excavation, shoring is less commonly needed than in conventional trenching because hydrovac excavations are typically narrower and workers do not normally enter the excavation. However, when hydrovac excavations exceed 5 feet in depth and a worker must enter for utility repair, inspection, or installation work, OSHA's cave-in protection requirements apply.

The competent person on site is responsible for determining whether shoring or another form of cave-in protection is needed. This determination is based on soil classification (Type A, B, or C under OSHA's system), excavation depth, water conditions, and vibration from nearby operations. Even when shoring is not required by depth, the competent person may require it based on site-specific conditions.