All excavations 20 feet or less in depth which have vertically sided lower portions shall be shielded or supported to a height at least 18 inches above the top of the vertical side. All such excavations shall have a maximum allowable slope of 1:1.
What is the slope ratio for Type A soil?
Type A: This is the most stable of the soil classifications and implies that you have a slope angle of a 3/4:1 ratio, which means that for every foot of depth, the sides of the excavation will slope back three-quarters of a foot or a 53-degree angle.
What is a Class B soil?
Type B means: (i) Cohesive soil with an unconfined compressive strength greater than 0.5 tsf (48 kPa) but less than 1.5 tsf (144 kPa); or. (ii) Granular cohesionless soils including: angular gravel (similar to crushed rock), silt, silt loam, sandy loam and, in some cases, silty clay loam and sandy clay loam.
Can you slope Type C soil?
Therefore, it is not safe to cut steps into a slope of type C soil because the soil’s lack of cohesion is likely to cause the steps to crumble when an employee steps on them.
How deep do you need shoring?
Trenches 5 feet (1.5 meters) deep or greater require a protective system unless the excavation is made entirely in stable rock. If less than 5 feet deep, a competent person may determine that a protective system is not required.
What is Cohesionless soil with example?
Cohesionless soil is soil that contains elements that do not stick together. Soil analysis prior to construction provides information critical to the success of trenchless operations. Examples of cohesionless soil are sand and gravel. Cohesionless soil is also known as frictional soil.
What are the 6 types of soil?
There are six main soil types:
What is OSHA Type C soil?
Type C soil is the least stable type of soil. Type C includes granular soils in which particles don’t stick together and cohesive soils with a low unconfined compressive strength; 0.5 tons per square foot or less. Examples of Type C soil include gravel, and sand.