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FE Civil Geotechnical Engineering
Practice Test 2027 Edition | Updated
2026–27 Questions, Answers &
Rationales
1. A soil has a liquid limit of 62% and a plastic limit of 28%. What is its
plasticity index?
A. 28%
B. 34%
C. 62%
D. 90%
Answer: 34%
Rationale: The plasticity index is PI = LL − PL = 62 − 28 = 34%.
2. A saturated soil has a total unit weight of 120 pcf. If the water unit weight is
62.4 pcf, what is its submerged unit weight?
A. 42.4 pcf
B. 57.6 pcf
,C. 62.4 pcf
D. 120 pcf
Answer: 57.6 pcf
Rationale: The submerged unit weight is γ′ = γsat − γw = 120 − 62.4 = 57.6 pcf.
3. A soil has a void ratio of 0.75 and a specific gravity of solids of 2.70. What is
its dry unit weight?
A. 85.1 pcf
B. 95.4 pcf
C. 110.1 pcf
D. 168.5 pcf
Answer: 95.4 pcf
Rationale: γd = Gsγw/(1 + e) = (2.70)(62.4)/(1.75) ≈ 96.3 pcf; using standard
rounding gives approximately 96 pcf. Therefore, among the choices, 95.4 pcf is
the closest.
4. A soil has a water content of 18%, a specific gravity of 2.65, and a void ratio
of 0.70. What is its degree of saturation?
A. 42%
B. 68%
C. 82%
D. 100%
Answer: 68%
Rationale: S = wGs/e = (0.18)(2.65)/0.70 ≈ 0.681, or approximately 68%.
, 5. Which soil type generally exhibits the greatest permeability?
A. Clay
B. Silt
C. Fine sand
D. Gravel
Answer: Gravel
Rationale: Hydraulic conductivity generally increases dramatically as particle
size increases. Gravel typically has much larger interconnected voids than fine-
grained soils.
6. According to Darcy's law, the rate of groundwater flow through a soil is
directly proportional to:
A. Hydraulic gradient and cross-sectional area
B. Effective stress only
C. Soil plasticity index
D. Degree of compaction only
Answer: Hydraulic gradient and cross-sectional area
Rationale: Darcy's law is Q = kiA, where k is hydraulic conductivity, i is hydraulic
gradient, and A is cross-sectional area.
7. A constant-head permeability test has k = 2 × 10⁻³ cm/s, cross-sectional
area = 50 cm², hydraulic head loss = 30 cm, and specimen length = 15 cm.
What is the approximate discharge rate?
A. 0.002 cm³/s
B. 0.01 cm³/s
C. 0.20 cm³/s
D. 2.0 cm³/s
, Answer: 0.20 cm³/s
Rationale: Q = kiA = (0.002)(30/15)(50) = 0.20 cm³/s.
8. Which laboratory test is primarily used to determine the shear strength
parameters c and φ for a soil?
A. Atterberg limits test
B. Direct shear test
C. Hydrometer test
D. Specific gravity test
Answer: Direct shear test
Rationale: The direct shear test evaluates shear stress at failure under controlled
normal stress and can be used to determine cohesion and friction angle.
9. For a normally consolidated clay, the coefficient of earth pressure at rest is
approximately:
A. sin φ
B. 1 − sin φ
C. 1 + sin φ
D. tan φ
Answer: 1 − sin φ
Rationale: For normally consolidated soils, Jaky's relationship is K₀ ≈ 1 − sin φ′.
10.A soil has an effective friction angle of 30°. What is its approximate
coefficient of active earth pressure using Rankine theory?
FE Civil Geotechnical Engineering
Practice Test 2027 Edition | Updated
2026–27 Questions, Answers &
Rationales
1. A soil has a liquid limit of 62% and a plastic limit of 28%. What is its
plasticity index?
A. 28%
B. 34%
C. 62%
D. 90%
Answer: 34%
Rationale: The plasticity index is PI = LL − PL = 62 − 28 = 34%.
2. A saturated soil has a total unit weight of 120 pcf. If the water unit weight is
62.4 pcf, what is its submerged unit weight?
A. 42.4 pcf
B. 57.6 pcf
,C. 62.4 pcf
D. 120 pcf
Answer: 57.6 pcf
Rationale: The submerged unit weight is γ′ = γsat − γw = 120 − 62.4 = 57.6 pcf.
3. A soil has a void ratio of 0.75 and a specific gravity of solids of 2.70. What is
its dry unit weight?
A. 85.1 pcf
B. 95.4 pcf
C. 110.1 pcf
D. 168.5 pcf
Answer: 95.4 pcf
Rationale: γd = Gsγw/(1 + e) = (2.70)(62.4)/(1.75) ≈ 96.3 pcf; using standard
rounding gives approximately 96 pcf. Therefore, among the choices, 95.4 pcf is
the closest.
4. A soil has a water content of 18%, a specific gravity of 2.65, and a void ratio
of 0.70. What is its degree of saturation?
A. 42%
B. 68%
C. 82%
D. 100%
Answer: 68%
Rationale: S = wGs/e = (0.18)(2.65)/0.70 ≈ 0.681, or approximately 68%.
, 5. Which soil type generally exhibits the greatest permeability?
A. Clay
B. Silt
C. Fine sand
D. Gravel
Answer: Gravel
Rationale: Hydraulic conductivity generally increases dramatically as particle
size increases. Gravel typically has much larger interconnected voids than fine-
grained soils.
6. According to Darcy's law, the rate of groundwater flow through a soil is
directly proportional to:
A. Hydraulic gradient and cross-sectional area
B. Effective stress only
C. Soil plasticity index
D. Degree of compaction only
Answer: Hydraulic gradient and cross-sectional area
Rationale: Darcy's law is Q = kiA, where k is hydraulic conductivity, i is hydraulic
gradient, and A is cross-sectional area.
7. A constant-head permeability test has k = 2 × 10⁻³ cm/s, cross-sectional
area = 50 cm², hydraulic head loss = 30 cm, and specimen length = 15 cm.
What is the approximate discharge rate?
A. 0.002 cm³/s
B. 0.01 cm³/s
C. 0.20 cm³/s
D. 2.0 cm³/s
, Answer: 0.20 cm³/s
Rationale: Q = kiA = (0.002)(30/15)(50) = 0.20 cm³/s.
8. Which laboratory test is primarily used to determine the shear strength
parameters c and φ for a soil?
A. Atterberg limits test
B. Direct shear test
C. Hydrometer test
D. Specific gravity test
Answer: Direct shear test
Rationale: The direct shear test evaluates shear stress at failure under controlled
normal stress and can be used to determine cohesion and friction angle.
9. For a normally consolidated clay, the coefficient of earth pressure at rest is
approximately:
A. sin φ
B. 1 − sin φ
C. 1 + sin φ
D. tan φ
Answer: 1 − sin φ
Rationale: For normally consolidated soils, Jaky's relationship is K₀ ≈ 1 − sin φ′.
10.A soil has an effective friction angle of 30°. What is its approximate
coefficient of active earth pressure using Rankine theory?
