Preventing cave-ins and excavation hazards
Scenario: Gordon was working in an excavation 13 feet deep and 6 feet wide. He had 10 years of experience in excavation work and knew what he was doing. Andy, a new employee who had never done excavation work, was in the trench with Gordon.
Just about mid-morning, Gordon saw a tension crack in the trench wall that he didn’t notice before. Shortly thereafter, a section of the wall began to break off. Gordon knew that the road near the excavation had had heavy equipment traffic on it yesterday. He decided to get out of the trench and told Andy to go first.
“Why?” Andy asked. Gordon told him to get up the ladder and he would explain later. Andy climbed first, followed by Gordon. He told Andy to find Jim, the site’s competent person. Just as Andy started to question Gordon about this, the far trench wall collapsed. What should happen next?
Gordon should report the incident.
An investigation should be performed to determine why the trench collapsed.
Andy should receive additional training in excavation hazards and jobsite safety and health program.
Click below to see the answer.
Preventing cave-ins and excavation hazards: Answer
What are the issues?
- Tension cracks in the trench
- Collapsed trench wall.
What did Gordon do right?
- Was observant of the conditions of the trench wall.
- Understood the hazards of working in a trench.
- Took control of the situation and made Andy get out of the trench first.
- Informed competent person immediately.
What went wrong? In this case, procedures were followed correctly.
Training tips
- Tension cracks in walls of, slopes of, or the ground near the excavation.
- Ground settlement or sinking.
- Changes in wall slope or bulging walls.
- Increase in strut loads.
- Spalling (breaking off in slabs) of soil.
- Sloughing (crumbling or falling away) of soil.
- Excessive seepage and piping of fine soils.
- Softening of sidewalls.
- Boiling of trench bottom.
- Creaking or popping sounds.
- Visual deformation of bracing system.
The presence of any of these signs indicates that your employees should not enter a trench. If they are in the trench, they should get out immediately. In either case, the problem should be reported to the supervisor or competent person.