What is the angle of a 15-foot deep trench in type "C" soil?

In type "C" soil, which is characterized as cohesionless and has the least stability among the soil classifications outlined by OSHA, the recommended angle for a trench is typically about 34 degrees from the horizontal. This angle reflects the need for proper safety measures when working with trenches of significant depth, such as the 15-foot trench mentioned in the question.

The steepness of 34 degrees for a trench in type "C" soil is designed to minimize the risk of cave-ins, which are more common in this type of soil due to its loose structure. According to OSHA guidelines, the maximum allowable depth for a trench in type "C" soil without shoring is 5 feet. However, at depths greater than that, proper protective systems such as trench boxes or shoring must be implemented due to the increased risk.

Understanding the angle associated with type "C" soil helps in ensuring that safety protocols are adhered to, protecting workers from potential hazards while working in or near trenches. The correct angle reflects industry best practices to mitigate risks associated with soil type, trench depth, and the unique characteristics of the soil at the site.