EGR 256 - Exam 1 | Questions and Correct Answers
Graded A+ | 2026\2027 Latest Edition
S: Degree of Saturation
-Correct Answer-S = Vw/Vv
γ: Moist (bulk) Unit Weight (lb/ft^3)
-Correct Answer-γ = W/V
γd: Dry Unit Weight (Ww = 0)
-Correct Answer-γd = Ws/V
γsat: Saturated Unit Weight (Va = 0)
-Correct Answer-γsat = (Ws+Ww) / V
γs: Solid Unit Weight
-Correct Answer-γs = Ws/Vs
γw: Water Unit Weight
-Correct Answer-γw = Ww/Vw
γ': Submerged Unit Weight
-Correct Answer-γ' = γsat - γw
Unit Weight of Water (γw)
-Correct Answer-9.81 kN/m^3
62.4 lb/ft^3
Relationship between γd, γsat, and γ
-Correct Answer-γd < γ < γsat
Gs: Specific Gravity
-Correct Answer-Gs = γs/γw
Dr: Relative Density
-Correct Answer-• In-situ measure of denseness or looseness of granular soil in the field
• Relevant for compaction
Dr = (emax-e)/(emax-emin)
Typical e Values
, -Correct Answer-• Dense sand: 0.3 - 0.6
• Loose sand: 0.6 - 1.0
• Clay: 0.6 - 1.5 (it can be higher)
• e = 0 is impossible (no voids)
Atterburg Limits
-Correct Answer-moisture contents (w%) between states
Liquid Limit (LL)
-Correct Answer-The moisture content above which the soil behaves as a liquid
(between plastic and liquid states)
- Casagrande Test (25 blows)
If: Flow Index
-Correct Answer-Slope of the log scale in a LL Test (N = # blows, w = moisture content)
One - Point Method
-Correct Answer-Used to determine the liquid limit when only one test is run for a soil.
Plastic Limit (PL)
-Correct Answer-Between semi solid and plastic states. Water content at which the soil
begins to crumble when rolled out into thin threads.
Chemical Weathering
-Correct Answer-
• chemical reactions
• changes mineral composition
• strongly affects plasticity + compressibility
Soil Classification based on Sieve Analysis
-Correct Answer-
- Gravel: retained on No. 4 sieve
- Sand: retained No. 200 to No. 4
- Fines (Silt and clays): pass No. 200
Sieve Analysis
-Correct Answer-Series of sieves with decreasing openings
• Mass retained measured on each sieve
• Used mainly for sands and gravels
• Results expressed as percent passing
Graded A+ | 2026\2027 Latest Edition
S: Degree of Saturation
-Correct Answer-S = Vw/Vv
γ: Moist (bulk) Unit Weight (lb/ft^3)
-Correct Answer-γ = W/V
γd: Dry Unit Weight (Ww = 0)
-Correct Answer-γd = Ws/V
γsat: Saturated Unit Weight (Va = 0)
-Correct Answer-γsat = (Ws+Ww) / V
γs: Solid Unit Weight
-Correct Answer-γs = Ws/Vs
γw: Water Unit Weight
-Correct Answer-γw = Ww/Vw
γ': Submerged Unit Weight
-Correct Answer-γ' = γsat - γw
Unit Weight of Water (γw)
-Correct Answer-9.81 kN/m^3
62.4 lb/ft^3
Relationship between γd, γsat, and γ
-Correct Answer-γd < γ < γsat
Gs: Specific Gravity
-Correct Answer-Gs = γs/γw
Dr: Relative Density
-Correct Answer-• In-situ measure of denseness or looseness of granular soil in the field
• Relevant for compaction
Dr = (emax-e)/(emax-emin)
Typical e Values
, -Correct Answer-• Dense sand: 0.3 - 0.6
• Loose sand: 0.6 - 1.0
• Clay: 0.6 - 1.5 (it can be higher)
• e = 0 is impossible (no voids)
Atterburg Limits
-Correct Answer-moisture contents (w%) between states
Liquid Limit (LL)
-Correct Answer-The moisture content above which the soil behaves as a liquid
(between plastic and liquid states)
- Casagrande Test (25 blows)
If: Flow Index
-Correct Answer-Slope of the log scale in a LL Test (N = # blows, w = moisture content)
One - Point Method
-Correct Answer-Used to determine the liquid limit when only one test is run for a soil.
Plastic Limit (PL)
-Correct Answer-Between semi solid and plastic states. Water content at which the soil
begins to crumble when rolled out into thin threads.
Chemical Weathering
-Correct Answer-
• chemical reactions
• changes mineral composition
• strongly affects plasticity + compressibility
Soil Classification based on Sieve Analysis
-Correct Answer-
- Gravel: retained on No. 4 sieve
- Sand: retained No. 200 to No. 4
- Fines (Silt and clays): pass No. 200
Sieve Analysis
-Correct Answer-Series of sieves with decreasing openings
• Mass retained measured on each sieve
• Used mainly for sands and gravels
• Results expressed as percent passing
