New Mexico GF-9 Utility Lines Exam
Questions with Answers and Rationales| Latest Update| Guaranteed Pass
,Question 1. Under OSHA excavation standards (29 CFR 1926 Subpart P), a
trench is defined as an excavation that is:
A. Any excavation deeper than 4 feet
B. A narrow underground excavation that is deeper than it is wide, and no
wider than 15 feet at the bottom
C. Any excavation wider than it is deep
D. Any excavation regardless of shape or dimension
E. An excavation used only for pipe installation
Correct Answer: B
Rationale: OSHA defines a trench as a narrow excavation made below the
surface of the ground in which the depth is greater than the width, and the
width at the bottom is not greater than 15 feet. Excavations wider than this at
the bottom are treated under the broader excavation rules rather than the
trench-specific provisions.
Question 2. Per OSHA, a trench or excavation of what depth generally
requires a protective system (shoring, shielding, or sloping) unless it is
entirely in stable rock?
A. 3 feet or more
B. 5 feet or more
C. 8 feet or more
D. 10 feet or more
E. 15 feet or more
Correct Answer: B
Rationale: OSHA requires protective systems for excavations 5 feet or deeper,
unless the excavation is made entirely in stable rock. Excavations less than 5
feet deep may also require protection if a competent person determines there
is a potential for a cave-in.
Question 3. Who is authorized under OSHA to determine the appropriate
protective system for a trench and to inspect the excavation daily for
,hazards?
A. Any laborer on site
B. The competent person
C. Only a licensed professional engineer for every excavation
D. The equipment operator
E. The general contractor's office staff
Correct Answer: B
Rationale: OSHA requires a 'competent person' - someone capable of
identifying existing and predictable hazards and who has authority to take
prompt corrective action - to classify soil, select protective systems, and
conduct daily inspections of excavations before employee entry and as
conditions change.
Question 4. A competent person must inspect an excavation and its
protective systems:
A. Only once at the start of the project
B. Daily, before the start of work, and as needed throughout the shift as
conditions change (e.g., after a rainstorm)
C. Only when an employee requests it
D. Once per week regardless of conditions
E. Only if the excavation is over 20 feet deep
Correct Answer: B
Rationale: OSHA requires daily inspections by a competent person before
work begins and as needed throughout the shift, and additional inspections are
required after any event that could increase hazards, such as rainstorms,
increased water seepage, vibration, or changes in the excavation.
Question 5. According to OSHA soil classification, which soil type is the
most stable and allows for the steepest maximum allowable slope for an
unprotected excavation?
A. Type C
B. Type B
C. Type A
, D. Saturated soil regardless of classification
E. Submerged soil
Correct Answer: C
Rationale: Type A soil is the most stable/cohesive soil classification under
OSHA (e.g., clay, silty clay) and allows the steepest maximum allowable slope
for sloping/benching systems (3/4:1, or about 53 degrees). Type C soil is the
least stable and requires the flattest slope (1.5:1).
Question 6. Which of the following soils can NEVER be classified as Type
A under OSHA, regardless of its cohesive properties?
A. Soil that is fissured
B. Soil subject to vibration from heavy traffic, pile driving, or similar effects,
or previously disturbed soil
C. Soil with an unconfined compressive strength of 1.5 tons per square foot
or greater
D. Both A and B
E. None of the above; any cohesive soil can be Type A
Correct Answer: D
Rationale: OSHA specifically excludes fissured soil, soil subject to vibration,
previously disturbed soil, soil in a sloped/layered system where the layers dip
into the excavation, and soil with seeping water from being classified as Type
A, even if it otherwise meets the unconfined compressive strength criteria of
1.5 tsf or greater.
Question 7. A trench box (trench shield) used for protection in an
excavation functions primarily by:
A. Preventing a cave-in from occurring at all
B. Protecting workers within the structure if a cave-in occurs, rather than
preventing the cave-in itself
C. Compacting the surrounding soil
D. Eliminating the need for a competent person
E. Serving only as a walkway
Correct Answer: B
Questions with Answers and Rationales| Latest Update| Guaranteed Pass
,Question 1. Under OSHA excavation standards (29 CFR 1926 Subpart P), a
trench is defined as an excavation that is:
A. Any excavation deeper than 4 feet
B. A narrow underground excavation that is deeper than it is wide, and no
wider than 15 feet at the bottom
C. Any excavation wider than it is deep
D. Any excavation regardless of shape or dimension
E. An excavation used only for pipe installation
Correct Answer: B
Rationale: OSHA defines a trench as a narrow excavation made below the
surface of the ground in which the depth is greater than the width, and the
width at the bottom is not greater than 15 feet. Excavations wider than this at
the bottom are treated under the broader excavation rules rather than the
trench-specific provisions.
Question 2. Per OSHA, a trench or excavation of what depth generally
requires a protective system (shoring, shielding, or sloping) unless it is
entirely in stable rock?
A. 3 feet or more
B. 5 feet or more
C. 8 feet or more
D. 10 feet or more
E. 15 feet or more
Correct Answer: B
Rationale: OSHA requires protective systems for excavations 5 feet or deeper,
unless the excavation is made entirely in stable rock. Excavations less than 5
feet deep may also require protection if a competent person determines there
is a potential for a cave-in.
Question 3. Who is authorized under OSHA to determine the appropriate
protective system for a trench and to inspect the excavation daily for
,hazards?
A. Any laborer on site
B. The competent person
C. Only a licensed professional engineer for every excavation
D. The equipment operator
E. The general contractor's office staff
Correct Answer: B
Rationale: OSHA requires a 'competent person' - someone capable of
identifying existing and predictable hazards and who has authority to take
prompt corrective action - to classify soil, select protective systems, and
conduct daily inspections of excavations before employee entry and as
conditions change.
Question 4. A competent person must inspect an excavation and its
protective systems:
A. Only once at the start of the project
B. Daily, before the start of work, and as needed throughout the shift as
conditions change (e.g., after a rainstorm)
C. Only when an employee requests it
D. Once per week regardless of conditions
E. Only if the excavation is over 20 feet deep
Correct Answer: B
Rationale: OSHA requires daily inspections by a competent person before
work begins and as needed throughout the shift, and additional inspections are
required after any event that could increase hazards, such as rainstorms,
increased water seepage, vibration, or changes in the excavation.
Question 5. According to OSHA soil classification, which soil type is the
most stable and allows for the steepest maximum allowable slope for an
unprotected excavation?
A. Type C
B. Type B
C. Type A
, D. Saturated soil regardless of classification
E. Submerged soil
Correct Answer: C
Rationale: Type A soil is the most stable/cohesive soil classification under
OSHA (e.g., clay, silty clay) and allows the steepest maximum allowable slope
for sloping/benching systems (3/4:1, or about 53 degrees). Type C soil is the
least stable and requires the flattest slope (1.5:1).
Question 6. Which of the following soils can NEVER be classified as Type
A under OSHA, regardless of its cohesive properties?
A. Soil that is fissured
B. Soil subject to vibration from heavy traffic, pile driving, or similar effects,
or previously disturbed soil
C. Soil with an unconfined compressive strength of 1.5 tons per square foot
or greater
D. Both A and B
E. None of the above; any cohesive soil can be Type A
Correct Answer: D
Rationale: OSHA specifically excludes fissured soil, soil subject to vibration,
previously disturbed soil, soil in a sloped/layered system where the layers dip
into the excavation, and soil with seeping water from being classified as Type
A, even if it otherwise meets the unconfined compressive strength criteria of
1.5 tsf or greater.
Question 7. A trench box (trench shield) used for protection in an
excavation functions primarily by:
A. Preventing a cave-in from occurring at all
B. Protecting workers within the structure if a cave-in occurs, rather than
preventing the cave-in itself
C. Compacting the surrounding soil
D. Eliminating the need for a competent person
E. Serving only as a walkway
Correct Answer: B
