What Happens in a Trench Collapse?

Official Bureau of Labor Statistics numbers show that excavation and trench-related fatalities doubled in 2016 over the previous five years. Trench collapses and cave-ins are some of the most dangerous situations workers can encounter. Individuals and companies can be found liable in the case of severe injury or death on the worksite. To prevent serious accidents, it’s important to know what’s happening when a trench collapses.

Trench cave-ins occur when gravity overcomes the soil’s ability to support its weight. Knowing that the overall stability of soil depends on soil strength, gravitational factors, and environmental factors, workers need to be aware of the conditions in which they are working. Soil cohesion, porosity, and moisture level are important factors, as are adjacent excavations, trench depth, and weather conditions, among many others.

Excavation removes the lateral support for trench walls. The soil at the bottom of the trench can bulge in – due to the weight of the soil above it – causing the trench lip to slide down. Soil at the back of the trench face holds and pulls on the soil at the trench face, creating stress at a right angle to the wall. This ultimately causes surface cracks parallel to the trench – the next step is a collapse.

Some indicators of potential trench failure:

  • Bulging soil at the bottom of a trench
  • Parallel tension cracks at the surface, leaning towards the trench
  • Sliding wedges of soil falling into the trench
  • Falling rock sections or chips of soil falling on the sides of the trench or the sliding of layered soils

Plan ahead to protect from trench collapse. Allen Trench Safety can help you determine which product is best for your application, so contact us for individualized product plans. Additionally, OSHA promotes trench safety through their Slope it, Shore it, Shield it campaign. Their goal is to protect workers in trenches. Find out more and download additional resources by clicking here. Ready to talk to a trench safety expert at Allen Trench Safety? Call us at (877) 854-3552.