513 EM 385-1-1 Chapters 23-29

Sections

25-8. General Requirements.

Protective Systems

Protective systems must withstand all expected loads and guard against dangers from moving ground. Employ methods like support systems or sloping.
Excavations under 5 feet in depth, examined and deemed safe by a CP, are exempt from protective systems, but still require a fixed egress.
For excavations over 5 feet deep or unstable soil, implement benching, sloping, or support systems approved by the USACE supervisor, KO, or COR, and halt work if any hazards like potential cave-ins are detected.

Stability of Adjacent Structures

Avoid excavation beneath structures unless a support system is in place or an RPE confirms the excavation won't endanger the structure.
An RPE must design support for excavations that threaten the stability of neighboring structures.
Protect and support sidewalks, pavements, or related structures when undermined by excavation.

Protection from Water

Prevent water entry into excavations with ditches, dikes, or similar methods and ensure good drainage around the excavation.
Do not work in excavations with water accumulation unless controlled by methods directed and planned by an RPE, with continuous monitoring and emergency measures in place.

Protection from Falling Material

Shield employees from potential hazards like loose rock or soil on excavation walls using methods like scaling, benching, or barricading.
Clear or secure any material that might slide or roll into the excavation and store excavated materials at least 2 feet away from the edge to prevent collapse.
Ensure upper-level work on excavations doesn't endanger workers below by implementing adequate protective measures.

Knowledge Check Choose the best answer for the question.

25-6. When must protective systems be installed in excavations?

If spoils are over 2 feet from the excavation edge

If excavations of any depth regardless of soil conditions

When excavations are over 4 feet deep in unstable soil

For excavations over 5 feet deep or unstable soil

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EM 385-1-1 Paragraph 25-8 (a.–d.).

25-8. General Requirements. (a.–d.).

The requirements of this chapter are applicable to all Government and contractor work forces when their employees are performing excavation or trenching activities.

a.  Protective Systems. (25-8.a)

(1)  Protective systems must have the capacity to resist without failure all loads that are intended or could reasonably be expected to be applied or transmitted to the system.

(2)  Guard the sides of all excavations in which employees are exposed to danger from moving ground by a support system, sloping or benching of the ground, or other equivalent means.

(3)  A protective system is not required for excavations less than 5 feet (1.5 m) in depth and which a CP examines, determines, and documents that there is no potential for cave-in. However, a fixed means of egress must be still provided.

(4)  Slope and bench according to paragraph 25-8.i.

(5)  Use and install support systems according to paragraph 25-8.j.

(6)  Shore unstable soil or excavations deeper than 5 feet (1.5 m) unless benching, sloping, or another acceptable plan is implemented and approved by the USACE supervisor or accepted by the KO or COR.

(7)  If evidence of a situation that could result in possible cave-ins, slides, failure of protective systems, hazardous atmospheres, or other hazardous condition is identified, remove exposed workers from the hazard and stop all work in the excavation until all necessary safety precautions have been implemented.

b.  Stability of Adjacent Structures.  (25-8.b)

(1)  Except in stable rock, do not excavate below the level of the base of footing of any foundation or retaining wall unless one of the following is met:

(a)  A support system, such as underpinning, is provided to ensure the stability of the structure and to protect employees involved in or adjacent to the excavation work.

(b)  An RPE has determined that the structure is sufficiently removed from the excavation so that it is not affected by the excavation and the excavation will not pose a hazard to employees.

(2)  If the stability of adjoining buildings or walls is endangered by excavations, then an RPE must design the shoring, bracing, or underpinning to ensure the stability of the structure and to protect employees.

(3)  Do not undermine sidewalks, pavements, and related structures unless a support system is provided to protect employees and the sidewalk, pavement, or related structure.

(4)  Where it is necessary to undercut the side of an excavation, safely support the overhanging material.

c.  Protection from Water.  (25-8.c)

(1)  Use diversion ditches, dikes, or other means to prevent surface water entering an excavation and to provide good drainage of the area adjacent to the excavation.

(2)  Do not work in excavations in which there is accumulated water or in which water is accumulating unless the water hazards posed by accumulation is controlled.

(a)  An RPE must plan and direct freezing, pumping, drainage, and similar control measures. Address existing moisture balances in surrounding soils and the effects on foundations and structures if it is disturbed.

(b)  When continuous operation of ground water control equipment is necessary, provide an emergency power source.  The CP must monitor water control equipment and operations to ensure proper operation.

d.  Protection from Falling Material.  (25-8.d)

(1)  Protect employees from loose rock or soil that could create a hazard by falling from the excavation wall by scaling, ice removal, benching, barricading, rock bolting, wire mesh, or other means.  Give special attention to slopes that may be adversely affected by weather, moisture content, or vibration.

(2)  Remove or make safe materials (for example, boulders, stumps) that may slide or roll into the excavation.

(3)  Place excavated material at least 2 feet (0.6 m) from the edge of an excavation or retain it using devices that are sufficient to prevent the materials from falling into the excavation.  In any case, place material at a distance to prevent excessive loading on the face of the excavation.

(4)  Do not work on the faces of sloped or benched excavations at levels above other employees except when employees at lower levels are adequately protected from the hazard of falling material or equipment.