Topic 3

Question 1

The fatality rate for excavation work is ___ higher than the rate for geenral construction.

Answer 1

112%

Question 2

OSHA reports ___ trench deaths in 2022 - more than double 2021 toll

Answer 2

39

Question 3

is any man-made cut, cavity or depression in an earth surface that is formed by earth removal

Answer 3

Excavation

Question 4

is a narrow excavation where the depth of a trench is greater than its width and the width measured at the bottom is not greater that 15 ft

Answer 4

Trench Excavation

Question 5

Hazards of Excavation Works

Answer 5

Soil Collapse
Falling Objects
Underground Utilities
Working Surfaces
Confined Space Conditions

Question 6

Types of Soil Collapse

Answer 6

Sliding
Bulge
Toppling
Boiling
Heave

Question 7

Principal Causes of Soil Collapse

Answer 7

Steep Cutting Angle
Super Imposed Load
Shock and Vibration
Water Pressure
Drying

Question 8

is a mixture of rock, water, air, and a variety of other substances

Answer 8

Soil

Question 9

Soil Types

Answer 9

Stable Rock
Type A
Type B
Type C

Question 10

Natural solid mineral matters

Answer 10

Stable Rock

Question 11

Cohesive soil with unconfined compressive strength of 1.5 tons per square foot or greater

Answer 11

Type A

Question 12

Cohesive soil with strength greater than 0.5 tsf but less than 1.5 tsf

Answer 12

Type B

Question 13

Cohesive soil strength 0.5 tsf or less

Answer 13

Type C

Question 14

pose the greatest risk to workers’ lives

Answer 14

Trench collapses, or cave-ins

Question 15

Trenches 5 feet (1.5 meters) deep or greater require a ______ unless the excavation is made entirely in stable rock

Answer 15

protective system

Question 16

Trenches 20 feet (6.1 meters) deep or greater require that the protective system be designed by a _________ or be based on tabulated data prepared and/or approved by a _________ in accordance with 1926.652(B) and (C)

Answer 16

registered professional engineer

Question 17

is an individual who is capable of identifying existing and predictable hazards or working conditions that are hazardous, unsanitary, or dangerous to workers

Answer 17

competent person

Question 18

Keep heavy equipment away from ______

Answer 18

trench edges

Question 19

keep excavated soil (spoils) and other materials at least ______ from trench edges

Answer 19

2 feet (0.6 meters)

Question 20

know where underground utilities are located before ___

Answer 20

digging

Question 21

test for atmospheric hazards such as low oxygen, hazardous fumes and toxic gases when ___deep

Answer 21

> 4 feet

Question 22

inspect trenches following a ___ or other water intrusion

Answer 22

rainstorm

Question 23

do not work under ___ or raised loads and materials

Answer 23

suspended

Question 24

ensure that personnel wear ______ or other suitable clothing when exposed to vehicular traffic

Answer 24

high visibility

Question 25

Types of Protective Systems

Answer 25

Benching Sloping Shoring Shielding

Question 26

means a method of protecting workers from cave-ins by excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels

Answer 26

Benching

Question 27

involves cutting back the trench wall at an angle inclined away from the excavation

Answer 27

Sloping

Question 28

requires installing aluminum hydraulic or other types of supports to prevent soil movement and cave-ins

Answer 28

Shoring

Question 29

protects workers by using trench boxes or other types of supports to prevent soil cave-ins

Answer 29

Shielding

Question 30

means loosening and taking out materials leaving space above or below ground

Answer 30

Excavation

Question 31

Advantages of using the Mechanical Plant in Excavation

Answer 31

Work Done Quicker Avoid the Dangerous Condition of Work by Human Workers Achieve Greater Depth Use Fewer Manpower and Work Done at Lower Cost

Question 32

are constructed in order to prevent erosion and sedimentation, and in some cases as a means to provide for a safe working environment during excavation by controlling surface runoff

Answer 32

Berms

Question 33

___ posted to prevent the public from going near the excavation

Answer 33

Signs

Question 34

Walkways or bridges has minimum clear width of ___

Answer 34

20 in

Question 35

Walkways or bridges has an extended a minimum of ___ past the surface edges

Answer 35

24 in

Question 36

Excavation shall be kept free of ___ at all times

Answer 36

water

Question 37

In muddy areas, workers should be provided with ___ to reduce the hazard of slipping

Answer 37

boots

Question 38

Determine location of underground ____ and take necessary steps to prevent damage

Answer 38

facilities

Question 39

2 Major Methods for Controlling Ground Water

Answer 39

Pumping Technique Exclusion Technique

Question 40

Oxygen Deficient Atmosphere

Answer 40

less than 19.5% oxygen

Question 41

___ from decayed matter

Answer 41

methane

Question 42

Shoring or timbering in excavation over ___ deep shall be designed by a structural engineer and approved by the proper authority

Answer 42

6.6 m

Question 43

No excavation in an ___ building or structure shall be undertaken unless steps are taken to prevent danger to worker

Answer 43

adjacent

Question 44

Before shoring or timbering, the walls of an excavation shall be stripped of ______ or other materials that might slide or fall on workers

Answer 44

loose rocks

Question 45

Keep excavated material from the edge of the excavation to provide a clear berm not less than the _________

Answer 45

third of the depth of excavation

Question 46

Tools, materials, and machinery keep at least ___ away from the edge of the excavation

Answer 46

1m

Question 47

The top of the walls of an excavation more than ____ deep shall be barricaded to a height of at least ___

Answer 47

2m, 1m

Question 48

Every excavation shall have at least one ___ in every ___ of length which shall extend at 0.83 above the top

Answer 48

ladder, 16.6 m

Question 49

Every part of an excavation over 2m deep where workers work shall be inspected by the person in charge at least ___ everyday

Answer 49

once

Question 50

use of ______ or other means to free the area of such contaminants

Answer 50

exhaust ventilation