When digging a 10-foot trench, the sloping or shoring requirements depend on the soil type and other conditions 5, 6, 7. Here's a breakdown of factors to consider:
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Soil Classification: A "competent person" must classify the soil as Stable Rock, Type A, Type B, or Type C [1]. This classification is crucial for determining the appropriate slope [2].
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Sloping Options:
- Option 1 (Allowable Configurations and Slopes): You can slope the excavation at an angle no steeper than 1 1/2 horizontal to one vertical (34 degrees) [3]. This is generally for Type C soil [3].
- Option 2 (Appendices A and B): Use the guidelines in OSHA's appendices for maximum allowable slopes and configurations [3].
- Option 3 (Tabulated Data): Follow tabulated data (tables and charts) approved by a registered professional engineer [3]. A copy of this data must be available at the job site [3].
- Option 4 (Design by a Registered Professional Engineer): Have a registered professional engineer design the sloping and benching system [3]. The design must be in written form and include the slopes and configurations determined to be safe [3].
- Maximum Allowable Slopes: The maximum allowable slope depends on the soil type [2]:
- Type A Soil: Maximum slope of 3/4:1 (horizontal to vertical) [4]
- Type B Soil: Maximum slope of 1:1 (horizontal to vertical) [5]
- Type C Soil: Maximum slope of 1 1/2:1 (horizontal to vertical) [3]
- Stable Rock: Vertical sides are allowed if the rock is stable [6].
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Shoring Systems: As an alternative to sloping, you can use a shoring system [6]. This involves installing supports to prevent cave-ins [6].
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Competent Person: A "competent person" must inspect the excavation daily for any signs of potential cave-ins or other hazards [7]. They also need to be able to identify existing and predictable hazards in the surroundings [8].
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Additional Considerations:
- Surface Encumbrances: Remove or support any surface encumbrances that could be a hazard [9].
- Underground Installations: Identify and locate any underground utilities before excavating [9].
- Water Accumulation: Take precautions to prevent water accumulation in the excavation [10].
- Adjacent Structures: Ensure the stability of nearby structures [10].
Disclaimer: Regulations can vary and it is important to check with your local authorities for any specific requirements in Maryland.
Important Safety Note:
Always verify safety information with your organization's specific guidelines and local regulations.