513 EM 385-1-1 Chapters 23-29

Sections

Chapter 25: Excavation and Trenching

This chapter on excavation and trenching focuses on ensuring safe practices during excavation activities to prevent accidents and injuries.

Long deep trench with bracing and ladder

This chapter focuses on ensuring safe practices during excavation activities to prevent accidents and injuries.

It outlines the roles and responsibilities of personnel, including the Competent Person (CP), who is responsible for developing excavation plans, conducting hazard analyses, performing soil classification, and ensuring that all protective systems are in place and functional.

The chapter also details the requirements for protective systems, which include sloping, benching, shoring, and shielding to prevent cave-ins, and emphasizes the importance of protecting workers from potential hazards such as falling materials, water accumulation, and hazardous atmospheres.

It also highlights the proper planning and execution of excavation activities, including the identification and protection of underground utilities, the management of excavated materials, and ensuring stable adjacent structures.

Safety measures such as providing safe access and egress to excavation sites, implementing proper perimeter protection to prevent falls and equipment from entering excavations, and conducting regular inspections to identify and mitigate hazards are also discussed.

25-1. References.

EM 385-1-1 Paragraph 25-1.

25-1. References.

25-2. Definitions.

EM 385-1-1 Paragraph 25-2.

25-2. Definitions.

a.  Barricade. A physical obstruction (for example, tape, screens, cones) intended to warn of and limit access to a hazardous area.  (25-2.a)

b.  Benching. A method of protecting employees from cave-ins by cutting the sides of the excavation in the arrangement of one or more horizontal levels, usually with vertical or near-vertical walls between steps. (25-2.b)

c.  Cofferdam. A temporary structure used to keep water (and earth) out of an excavation during construction of the permanent structure.  (25-2.c)

d.  Competent Person (CP), Excavations.  A person designated in writing by the employer to be responsible for the immediate supervision, implementation, and monitoring of the Excavation and Trenching Plan.  Must have training, knowledge, and experience in excavation and trenching to be capable of identifying, evaluating, and addressing existing and potential hazards.  This individual must have the authority to take prompt corrective measures with regard to such hazards.  The term “Competent Person (CP)” as used in this chapter, refers to “Competent Person, Excavations.”
(25-2.d)

e.  Perimeter Protection.  Measures taken to prevent personnel, vehicles, and materials from falling into an excavation.  (25-2.e)

f.  Protective System. Methods used to protect employees from cave-ins, from material falling into an excavation, or from the collapse of adjacent structures.  Systems include benching, sloping, shoring, trench shields, underpinning, rock bolting, and similar.  (25-2.f)

g.  Scaling. The removal of loose, overhanging, protruding, or otherwise precariously positioned material from above or along the sides of an excavation. (25-2.g)

h.  Sloping.  A method of protecting employees from cave-ins by cutting the sides of the excavation in the arrangement of slopes.  The angle of the slope needed to prevent cave-in is a function of the soil type, environmental factors such as moisture and freezing weather, and the magnitude and location of any loads and vibration surcharged upon the slopes.  (25-2.h)

i.  Stable Rock. Natural, solid, mineral material that can be excavated with vertical sides and remain intact while exposed.  (25-2.i)

j.  Support System.  A structural means of supporting the walls of an excavation to prevent cave-ins. Systems include shields, shoring, underpinning, rock bolts, and similar.  (25-2.j)