Can Type C soil be benched?

Asked By: Ernestino Haider | Last Updated: 9th March, 2020
Category: business and finance civil engineering industry
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Appendix B does not permit an employer to bench a type C soil excavation. 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.

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Besides, can Type C soil be sloped?

OSHA requires type C soil to be sloped at 1½H:1V and it cannot be benched. This means that the slope must be cut back 1½ ft horizontally for every 1 ft of depth.

Likewise, what type of soil can be benched? Type A soils are cohesive with an unconfined compressive strength of 1.5 tons per square foot (tsf) or greater. Examples include clay, silty clay, sandy clay and clay loam. Type A soil may also be “benched,” or set at specific angles for employee protection.

Similarly one may ask, can Class C Soil be benched?

Assume TYPE C soil. This gives a maximum allowable slope of 34 degrees (1.5H: 1V). No benching is allowed.

What is the slope ratio for Type C soil?

A. Sloping

Soil type Height:Depth ratio Slope angle
Type B 1:1 45°
Type C 1½:1 34°
Type A(short-term) ½:1 63°
(For a maximum excavation depth of 12 ft)

34 Related Question Answers Found

What is the most stable soil type?

Solid Rock is the most stable, and Type C soil is the least stable. Soils are typed not only by how cohesive they are, but also by the conditions in which they are found.

What are the 3 types of soil?

There are three basic types of soil: sand, silt and clay. But, most soils are composed of a combination of the different types.

What are the three methods of excavation?

There are number of excavation methods which are used for deep foundation construction such as full open cut method, bracing excavation, anchored excavation, island excavation methods,zoned excavation, top down construction methods etc. These excavation techniques are discussed.

Which type of soil is the least stable and can contain sand gravel and soft clay?

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.

What type of soil is clay?

Clay Soil is a heavy soil type that benefits from high nutrients. Clay soils remain wet and cold in winter and dry out in summer. These soils are made of over 25 percent clay, and because of the spaces found between clay particles, clay soils hold a high amount of water.

What is the difference between shoring and shielding?

Shoring should not be confused with shielding by means of trench shields. Shoring is designed to prevent collapse, whilst shielding is only designed to protect workers should collapse occur. Most professionals agree that shoring is the safer approach of the two.

What type of soil is most common?

Most common garden plants prefer loam — soils with a balance of different-sized mineral particles (approximately 40% sand, 40% silt, and 20% clay) with ample organic matter and pore space. However, some plants grow better in sandy soils, while others are well-adapted to clay soils.

What is granular soil?

Granular soil means gravel, sand, or silt (coarse grained soil) with little or no clay content. Granular soil has no cohesive strength. Some moist granular soils exhibit apparent cohesion . Granular soil cannot be molded when moist and crumbles easily when dry.

How can you control water around an excavation?

Exclusion Methods to Control Ground Water in Excavations
There are number of techniques by which ground water exclusion are obtained: Forming impervious barriers by grouting with cement, clay suspension. Chemical consolidation for controlling ground water in excavation. Ground water control by compressed air.

What is cohesive soil?

Cohesive soil is defined as sticky soil, and can be termed as clay or silty clay. The surface tension of capillary water exerts the capillary forces, which reduces the soil strength. Example for cohesive soil is clay, and it contains very fine particles which can hold water to increase volume of soil particle.

What is the maximum allowable slope for Type B soil?

Soil or Rock Type Max Slope (H:V) Max Slope (degrees)
Stable Rock Vertical 90
Class "A" 3/4 : 1 53
Class "B" 1 : 1 45
Class "C" 3/2 : 1 34

What are the properties of cohesive soil?

Most commonly used characteristics for cohesive soils are boundaries of fine-stratification, grain-size distribution, consistency limits, maximum and minimum density, specific gravity, organic matter, moisture content, dry density, porosity, permeability, void ratio, compression index, and shear strength.

How do you find trench slope?

(based on chart slope is 3/4:1) 75% of 12 = 8. Add the length at the top of the excavation to the length at the bottom of the excavation and divide by 2 to get the average length. Do the same for the width. Multiply the average length times the average width times the average depth and divide by 27.

Are trenches considered confined space?

Open trenches and excavations such as building foundations aren't generally considered confined spaces; they are regulated under OSHA's excavation standard, 29 CFR Part 1926, Subpart P. It's a space large enough to bodily enter, has limited or restricted means of entry/exit and is not designed for continuous occupancy.

What are used to prevent soil movement and cave ins during the excavation of earth?

Protective Systems
Shoring requires installing aluminum hydraulic or other types of supports to prevent soil movement and caveins. Shielding protects workers by using trench boxes or other types of supports to prevent soil cave-ins.

What is benching in excavation?

Benching (Benching system) means a method of protecting employees from cave-ins by excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels.

What is benching and sloping?

This appendix contains specifications for sloping and benching when used as methods of protecting employees working in excavations from cave-ins. Actual slope means the slope to which an excavation face is excavated. Distress means that the soil is in a condition where a cave-in is imminent or is likely to occur.