Soil Mechanics Final
TF: The diffuse double layer is the basic structure of each clay particle, and these clay
particle diffuse double layers are the 2 different mineral sheets bonded together -
✔️✔️False. The diffuse double layer is the region of attracted positive ions in solution
and the negatively charged surface of the clay
What is the name of the lab test that is used to determine the grain size distribution of
the particles of fine soil, that pass through the No. 200 sieve? - ✔️✔️Hydrometer
Analysis
What is the sieve number that is used to separate fine sand from medium sand? -
✔️✔️40
What is the grain size diameter (in mm) that is the dividing line between fines and sand
particles sizes? - ✔️✔️0.075
The plastic limit test involves rolling out a soil thread until it just breaks into smaller
pieces when thread is what diameter? - ✔️✔️1/8 inch
List the 4 conditions necessary for Liquefaction to occur in a natural sand deposit -
✔️✔️Loose soil, fine sand, below GWT, earthquakes
TF: A clay soil is considered to be at its liquid limit when the slot closes for 1/2 inch of its
length at 35 drops of the brass cup - ✔️✔️False. 25 drops
TF: All the clay soils exhibit the same behavior and shear strength when at their Liquid
Limit, even if one clay has LL=130% and another clay has LL=25% - ✔️✔️True
List the three most common clay minerals that were discussed in class -
✔️✔️Montmorillonite, Kaolinite, Illite
Which common clay mineral has the most potential for shrink and swell when water
content changes? - ✔️✔️Montmorillonite
TF: Clay soils usually have a void ratio that is greater than 1.0, but not sand. -
✔️✔️True
Which of the following 4 USCS classified soils would be best for use as an impervious
cap over a landfill, that must provide: impermeability, resistance to shrink-swell, and
relative ease of compaction - ✔️✔️CL
, If a sand soil has a void ratio value of 0.30, then what term best describes its density? -
✔️✔️Very dense
What is the symbol for porosity? - ✔️✔️n
What is the symbol for void ratio? - ✔️✔️e
What is the equation for the degree of saturation? - ✔️✔️s=(Vw/Vv)*100%
What is the equation for the degree of water content? - ✔️✔️w=(Ww/Ws)*100%
What is the equation for the specific gravity? - ✔️✔️s=(Ws/(Vs*Gammaw)
A soil with 4% fines, and 51% passing the No. 4 sieve, with a Cu=5.2 and Cc=1.5 will be
classified as which of the following? - ✔️✔️GW
In the USCS system, write the three words that describe a soil classified as ML soil? -
✔️✔️Low plasticity silt
TF: In working with a "performance" specification, only the required percent compaction
is specified, but often the allowable range of moisture content is also specified -
✔️✔️True
Make a sketch to the right of the soil fabric that results from compacting clay soil that is
dry of optimum w.c. - ✔️✔️Particles are more spread out. Higher permeability and the
particles stick together better
ASTM test specification says that all the soil of a sample being tested in the lab Proctor
test must pass through a No. 4 sieve if the 4-inch diameter compaction mold is to be
used. If larger soil particles are present, what mold size must be used? - ✔️✔️6 inch
TF: To achieve good degree of compaction throughout the lift thickness of a clayey soil,
the thickness of loose placed fill before compaction should not exceed about 8-10
inches - ✔️✔️True
TF: The sheepsfoot roller is most often used to compact plastic clay soils because the
small peg-like feet apply the high stresses needed to shear through the clay and
manipulate the clay soils into denser condition - ✔️✔️True
What should be the water content of clay soil being compacted for a landfill liner or as
core of an earth-fill dam, both of which need to have very slow permeability? -
✔️✔️Wet of Optimum
TF: The diffuse double layer is the basic structure of each clay particle, and these clay
particle diffuse double layers are the 2 different mineral sheets bonded together -
✔️✔️False. The diffuse double layer is the region of attracted positive ions in solution
and the negatively charged surface of the clay
What is the name of the lab test that is used to determine the grain size distribution of
the particles of fine soil, that pass through the No. 200 sieve? - ✔️✔️Hydrometer
Analysis
What is the sieve number that is used to separate fine sand from medium sand? -
✔️✔️40
What is the grain size diameter (in mm) that is the dividing line between fines and sand
particles sizes? - ✔️✔️0.075
The plastic limit test involves rolling out a soil thread until it just breaks into smaller
pieces when thread is what diameter? - ✔️✔️1/8 inch
List the 4 conditions necessary for Liquefaction to occur in a natural sand deposit -
✔️✔️Loose soil, fine sand, below GWT, earthquakes
TF: A clay soil is considered to be at its liquid limit when the slot closes for 1/2 inch of its
length at 35 drops of the brass cup - ✔️✔️False. 25 drops
TF: All the clay soils exhibit the same behavior and shear strength when at their Liquid
Limit, even if one clay has LL=130% and another clay has LL=25% - ✔️✔️True
List the three most common clay minerals that were discussed in class -
✔️✔️Montmorillonite, Kaolinite, Illite
Which common clay mineral has the most potential for shrink and swell when water
content changes? - ✔️✔️Montmorillonite
TF: Clay soils usually have a void ratio that is greater than 1.0, but not sand. -
✔️✔️True
Which of the following 4 USCS classified soils would be best for use as an impervious
cap over a landfill, that must provide: impermeability, resistance to shrink-swell, and
relative ease of compaction - ✔️✔️CL
, If a sand soil has a void ratio value of 0.30, then what term best describes its density? -
✔️✔️Very dense
What is the symbol for porosity? - ✔️✔️n
What is the symbol for void ratio? - ✔️✔️e
What is the equation for the degree of saturation? - ✔️✔️s=(Vw/Vv)*100%
What is the equation for the degree of water content? - ✔️✔️w=(Ww/Ws)*100%
What is the equation for the specific gravity? - ✔️✔️s=(Ws/(Vs*Gammaw)
A soil with 4% fines, and 51% passing the No. 4 sieve, with a Cu=5.2 and Cc=1.5 will be
classified as which of the following? - ✔️✔️GW
In the USCS system, write the three words that describe a soil classified as ML soil? -
✔️✔️Low plasticity silt
TF: In working with a "performance" specification, only the required percent compaction
is specified, but often the allowable range of moisture content is also specified -
✔️✔️True
Make a sketch to the right of the soil fabric that results from compacting clay soil that is
dry of optimum w.c. - ✔️✔️Particles are more spread out. Higher permeability and the
particles stick together better
ASTM test specification says that all the soil of a sample being tested in the lab Proctor
test must pass through a No. 4 sieve if the 4-inch diameter compaction mold is to be
used. If larger soil particles are present, what mold size must be used? - ✔️✔️6 inch
TF: To achieve good degree of compaction throughout the lift thickness of a clayey soil,
the thickness of loose placed fill before compaction should not exceed about 8-10
inches - ✔️✔️True
TF: The sheepsfoot roller is most often used to compact plastic clay soils because the
small peg-like feet apply the high stresses needed to shear through the clay and
manipulate the clay soils into denser condition - ✔️✔️True
What should be the water content of clay soil being compacted for a landfill liner or as
core of an earth-fill dam, both of which need to have very slow permeability? -
✔️✔️Wet of Optimum
