Minnesota Soils Special Inspector Exam
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary purpose of a soils special inspector is to:
A. Design foundations
B. Approve architectural drawings
C. Verify compliance with approved geotechnical and construction
requirements
D. Operate excavation equipment
Answer: C. Verify compliance with approved geotechnical and construction
requirements
Rationale: The inspector's role is to observe, document, and verify that soil-
related construction activities comply with approved plans, specifications,
and code requirements.
, 2. Which soil classification system is most commonly used in
geotechnical engineering?
A. ASTM Concrete Classification System
B. Unified Soil Classification System (USCS)
C. National Electrical Classification System
D. Structural Steel Classification System
Answer: B. Unified Soil Classification System (USCS)
Rationale: USCS classifies soils based on grain size distribution and
plasticity characteristics.
3. A soil sample containing more than 50% gravel-sized particles is
classified primarily as:
A. Clay
B. Silt
C. Gravel
D. Peat
Answer: C. Gravel
Rationale: Under USCS, coarse-grained soils with a majority of gravel-sized
particles are classified as gravels.
4. What is the purpose of field density testing?
,A. Measure soil color
B. Determine compaction effectiveness
C. Identify groundwater chemistry
D. Measure slope angle
Answer: B. Determine compaction effectiveness
Rationale: Field density testing verifies whether soil compaction meets
project specifications.
5. Standard Proctor testing is covered by which ASTM standard?
A. ASTM D698
B. ASTM D1557
C. ASTM D2487
D. ASTM D4318
Answer: A. ASTM D698
Rationale: ASTM D698 establishes procedures for Standard Proctor
compaction testing.
6. Modified Proctor testing is covered by:
A. ASTM D698
B. ASTM D1557
, C. ASTM D2216
D. ASTM D2488
Answer: B. ASTM D1557
Rationale: ASTM D1557 uses higher compaction energy than Standard
Proctor testing.
7. Optimum moisture content is defined as:
A. Lowest moisture level possible
B. Moisture content producing maximum dry density
C. Moisture at saturation only
D. Moisture in groundwater
Answer: B. Moisture content producing maximum dry density
Rationale: Maximum dry density is achieved at optimum moisture content
during compaction testing.
8. Which test commonly determines in-place soil density?
A. Slump test
B. Atterberg Limits test
C. Nuclear density gauge test
D. Air content test
Answer: C. Nuclear density gauge test
Practice Questions And Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The primary purpose of a soils special inspector is to:
A. Design foundations
B. Approve architectural drawings
C. Verify compliance with approved geotechnical and construction
requirements
D. Operate excavation equipment
Answer: C. Verify compliance with approved geotechnical and construction
requirements
Rationale: The inspector's role is to observe, document, and verify that soil-
related construction activities comply with approved plans, specifications,
and code requirements.
, 2. Which soil classification system is most commonly used in
geotechnical engineering?
A. ASTM Concrete Classification System
B. Unified Soil Classification System (USCS)
C. National Electrical Classification System
D. Structural Steel Classification System
Answer: B. Unified Soil Classification System (USCS)
Rationale: USCS classifies soils based on grain size distribution and
plasticity characteristics.
3. A soil sample containing more than 50% gravel-sized particles is
classified primarily as:
A. Clay
B. Silt
C. Gravel
D. Peat
Answer: C. Gravel
Rationale: Under USCS, coarse-grained soils with a majority of gravel-sized
particles are classified as gravels.
4. What is the purpose of field density testing?
,A. Measure soil color
B. Determine compaction effectiveness
C. Identify groundwater chemistry
D. Measure slope angle
Answer: B. Determine compaction effectiveness
Rationale: Field density testing verifies whether soil compaction meets
project specifications.
5. Standard Proctor testing is covered by which ASTM standard?
A. ASTM D698
B. ASTM D1557
C. ASTM D2487
D. ASTM D4318
Answer: A. ASTM D698
Rationale: ASTM D698 establishes procedures for Standard Proctor
compaction testing.
6. Modified Proctor testing is covered by:
A. ASTM D698
B. ASTM D1557
, C. ASTM D2216
D. ASTM D2488
Answer: B. ASTM D1557
Rationale: ASTM D1557 uses higher compaction energy than Standard
Proctor testing.
7. Optimum moisture content is defined as:
A. Lowest moisture level possible
B. Moisture content producing maximum dry density
C. Moisture at saturation only
D. Moisture in groundwater
Answer: B. Moisture content producing maximum dry density
Rationale: Maximum dry density is achieved at optimum moisture content
during compaction testing.
8. Which test commonly determines in-place soil density?
A. Slump test
B. Atterberg Limits test
C. Nuclear density gauge test
D. Air content test
Answer: C. Nuclear density gauge test
