Excavations and Trenches

Sloping

Forming sides of an excavation that are inclined away from the excavation so as to prevent cave-ins.

Type C soil

Granular soils including gravel, sand, and loamy sand Submerged soil r soil from which water is freely speeping or submerged rock that is not stable

Aluminum Hydraulic Shoring

How we mostly protect trenches

Protective Systems

Sloping, benching, support systems, shoring, and shields required where cave-in potential is high

Dry rock that is not stable

Type B soil

Hazardous Atmosphere

an atmosphere which by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating, oxygen deficient, toxic, or otherwise harmful, may cause death, illness, or injury

Ramp

an inclined walking or working surface that is used to gain access to one point from another, and is constructed from earth or from structural materials such as steel or wood.

Type B soil

angular gravel (similar to crushed rock), silt, silt loam, sandy loam and, in some cases, silty clay loam and sandy clay loam

Wales

horizontal members of a shoring system placed parallel to the excavation face whose sides bear against the vertical members of the shoring system or earth.

Trench

means a narrow excavation (in relation to its length) made below the surface of the ground. Width of the bottom of the trench os not greater than 15ft

Cave-In

the separation of a mass of soil or rock material from the side of an excavation

Accepted Engineering Practice

those requirements which are compatible with standards of practice required by a registered professional engineer

Shield

A structure which is able to to withstand the forces imposed on it by a cave-in and thereby protect employees within the structure.

Excavation

Any man-made cut, cavity, trench, or depression in an earth surface, formed by removing earth.

high a shield must be above a slope

18"

What is the maximum allowable slope for an excavation less than 20 feet in a type B soil?

1:1

Excavate below shield and spoil piles

2'

Max depth you can excavate a trench without a Registred Engineer

20'

Ladder above landing

3'

One cubic yard 3' x 3' x 3' weights

3000 lbs

Access/Egress Required

4'

At what depth must employees be protected from cave-ins in an excavation?

5 ft

Protective system is required

5'

Egress Spacing

50'

A 12" x 12" x 12" of soil weights

90-140lbs

Which of the following are approved employee protective systems for excavations?

Benching Sloping Shoring

There is not worst type soil than

C

Type A soil

Clay, silty clay, sandy clay, clay loam and, in some cases, silty clay loam and sandy clay loam. Cemented soils such as caliche and hardpan are also considered

Inspections

Every workday

Benching

Excavating the sides of the excavation to form one or a series of horizontal levels or steps.

Slopes

Type A - 3/4 H to 1 V slope ratio Type B - 1H to 1V slope ratio Type C - 1 1/2 H to 1 V slope ratio

Registered Professional Engineer

a person who is registered as a professional engineer in the state where the work is to be performed

Shoring

a structure such as a metal hydraulic, mechanical or timber shoring system that supports the sides of an excavation and which is designed to prevent cave-ins