Excavation work requires planning
All forms of excavation work require a large number of conditions to be met. For instance, there are set rules on how reinforcement is to be implemented in the case of major works, and what you should do when reinforcement is not possible. Remember that soil is heavy and a lot of soil is very heavy, so it is important that you pay attention to the rules.
Find out lots more here:
Manual for the safety group (pages 78-86)