Soil Safety Trench Quiz
OSH 379
Soil Safety / Trenching Safety Quiz
Week 5
1. Define “trench.”
a. A narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m). If forms or other structures are installed or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet (4.6 m) or less (measured at the bottom of the excavation), the excavation is also considered to be a trench.
2. Safety professionals must be concerned about two descriptors of soil from soil reports. What are they?
a. grain size, plasticity, and permeability
3. What does the term “well graded” mean in regards to grain size distribution?
a. It means that a sample is not missing certain amounts of grain sizes. It has a sufficient amount of all grain sizes in the given sample.
4. What are the signs of high concentrations of organic materials in soil?
a. Dark color, smell/gasses, visible organics
5. A soils report will report indications of water table levels and point out potential water issues in areas where trenches will be needed.
a. True
6. There are how many types of soil for OSHA trenching safety regulations? What are they?
a. Four. Stable Rock, Type A, Type B, and Type C
7. What is the strength of Type A soil?
a. cohesive soils with an unconfined, compressive strength of 1.5 ton per square foot (tsf) (144 kPa) or greater.
8. What is the standard sloping for Type A soil?
a. ¾ to 1
9. If a trench wall soil sample had a strength of 1.5 tsf, but did not pass the cohesive roll test, then what type of soil would be indicated only from the information given?
a. Type B
10. Regardless of other tests, if water was seeping from a trench wall, what type of soil would it be?
a. Class C
11. List the visual indications of non-cohesive soils. What physical test indicates
Soil Safety / Trenching Safety Quiz
Week 5
1. Define “trench.”
a. A narrow excavation (in relation to its length) made below the surface of the ground. In general, the depth is greater than the width, but the width of a trench (measured at the bottom) is not greater than 15 feet (4.6 m). If forms or other structures are installed or constructed in an excavation so as to reduce the dimension measured from the forms or structure to the side of the excavation to 15 feet (4.6 m) or less (measured at the bottom of the excavation), the excavation is also considered to be a trench.
2. Safety professionals must be concerned about two descriptors of soil from soil reports. What are they?
a. grain size, plasticity, and permeability
3. What does the term “well graded” mean in regards to grain size distribution?
a. It means that a sample is not missing certain amounts of grain sizes. It has a sufficient amount of all grain sizes in the given sample.
4. What are the signs of high concentrations of organic materials in soil?
a. Dark color, smell/gasses, visible organics
5. A soils report will report indications of water table levels and point out potential water issues in areas where trenches will be needed.
a. True
6. There are how many types of soil for OSHA trenching safety regulations? What are they?
a. Four. Stable Rock, Type A, Type B, and Type C
7. What is the strength of Type A soil?
a. cohesive soils with an unconfined, compressive strength of 1.5 ton per square foot (tsf) (144 kPa) or greater.
8. What is the standard sloping for Type A soil?
a. ¾ to 1
9. If a trench wall soil sample had a strength of 1.5 tsf, but did not pass the cohesive roll test, then what type of soil would be indicated only from the information given?
a. Type B
10. Regardless of other tests, if water was seeping from a trench wall, what type of soil would it be?
a. Class C
11. List the visual indications of non-cohesive soils. What physical test indicates