Key Questions
The following key questions are answered in this module:
How dangerous is excavation?
Excavating is one of the most dangerous operations in construction work. There are an average of 70 deaths each year in the U.S. due to excavation accidents, and thousands more injuries.
How can excavation accidents be prevented?
. due to excavation accidents, and thousands more injuries. Most excavation accidents could be prevented by following simple safety procedures. Knowing the types of soil and the properties of soil is very important in excavation work. Whether a soil is solid, cohesive, sandy, or wet will make a big difference in how excavation work is planned.
What is a competent person at an excavation site?
Every excavation operation must have what OSHA terms a competent person. The competent person plans and oversees an excavation operation. He or she is able to recognize any existing or potential excavation dangers as well as any other related dangers such as confined spaces or hazardous atmospheres. He or she must also have the authority to take appropriate actions to fix any problems that are found. The competent person also inspects the soil properties and performs soil tests to determine what the necessary safety precautions should be.
What causes most excavation casualities?
Most excavation fatalities are caused by cave-ins. Preventing cave-ins should be the top safety concern during excavation work.
What are the four primary types of soil?
The four primary types of soil are solid rock, type A, type B, and type C.
What is solid rock?
Solid rock is the most stable of all the soils; there is almost no chance of solid rock caving in.
What is type A soil?
Type A soil is the second-most stable soil type; it is made up of cohesive clay-like soil.
What is type B soil?
Type B soil is less cohesive than Type A; it poses a significant danger of cave-in.
What is type C soil?
Type C is a very sandy, granular soil that comes apart very easily. It is the most unstable type of soil.
Most trenching is done in which soil types?
Most trenching will be done in Type B or Type C soil because these are the most common soil types.
What are some signs of a possible cave-in?
Signs that a cave-in may occur include tension cracks, toppling, sliding or sluffing, bulging, heaving or squeezing, and boiling.