Geology
Geology Questions
1. The soil profile at a site consists of:
0 –8m Sand t=16kN/m3 Ko=0.5
8 –12m Clay t=20kN/m3 Ko=0.3
The water table is initially at a depth of 1m below the surface. The water table is to be rapidly lowered to a depth of 6m and maintained at that level permanently. Consider two points in the soil profile, Point A at a depth of 4m and Point B at a depth of 10m. Determine the effective vertical and horizontal stresses at Points A and B for two cases:
a) Initial conditions where the water table is 1m below the surface.
b) A long time after lowering the water table to 6m below the surface.
Answer for a:
Answer for b:
2. A level site consists of a deep deposit of sand having a total density of 1.7t/m3. The water table is 2m below the surface of the sand. During a period of wet weather the site is flooded such that 2m of water covers the site. Determine the change in vertical effective stress at a point 4m below the surface of the sand as a result of this flooding.
Answer:
3. An element of soil is subjected to the normal compressive stresses of 100 and 40kPa as shown in Figure 2. Shear stresses are now applied to the planes on which these stresses act. What is the magnitude of the shear stress which must be applied to those planes such that the plane of major principal stress in the element is horizontal?
Answer:
4. The stresses shown in Figure 3 are applied at a point in a soil mass. Determine the angle that the plane of major principal stress makes with the x-axis.
Answer:
Geology Questions
1.
The soil profile at a site consists of:
0
–
8m Sand
g
t
=16kN/m
3
K
o
=0.5
8
–
12m Clay
g
t=20kN/m
3
K
o
=0.3
The water table is initially at a depth of 1m below the surface. The water
table is to be rapidly lowered to a depth of 6m and maintained at that level
permanently. Consider two points in the soil profile, Point A at a depth of 4m
and Point B at a depth of 10m. Determine the effective vertica
l and horizontal
stresses at Points A and B for two cases:
a) Initial conditions where the water table is 1m below the surface.
b) A long time after lowering the water table to 6m below the surface.
Answer for a:
Answer for b:
2.
A level site consists o
f
a deep deposit of sand having a total density of
1.7t/m3. The water table is 2m below the
surface of the sand. During a period of wet
weather the site is flooded such that 2m of water covers the site. Determine the
change in vertica
l effective stress at a point 4m below the surface of the sand as a
result of this flooding.
Answer:
3.
An element of soil is subjected to the normal
compressive stresses of 100 and 40kPa as
shown in
Figure
2. Shear stresses are now
ap
plied to the planes on which these stresses act.
What is the magnitude of the shear stress which
must be applied to those planes such that the
plane of major principal stress in the element is
horizontal?
Answer:
4.
The stresses shown in Figure
3
ar
e applied at
a point in a soil mass. Determine the angle
that the plane of major principal stress makes
with the x
–
axis
.
Answer:
Geology Questions
1. The soil profile at a site consists of:
0 –8m Sand t=16kN/m
3
K
o
=0.5
8 –12m Clay t=20kN/m
3
K
o
=0.3
The water table is initially at a depth of 1m below the surface. The water
table is to be rapidly lowered to a depth of 6m and maintained at that level
permanently. Consider two points in the soil profile, Point A at a depth of 4m
and Point B at a depth of 10m. Determine the effective vertical and horizontal
stresses at Points A and B for two cases:
a) Initial conditions where the water table is 1m below the surface.
b) A long time after lowering the water table to 6m below the surface.
Answer for a:
Answer for b:
2. A level site consists of a deep deposit of sand having a total density of
1.7t/m3. The water table is 2m below the surface of the sand. During a period of wet
weather the site is flooded such that 2m of water covers the site. Determine the
change in vertical effective stress at a point 4m below the surface of the sand as a
result of this flooding.
Answer:
3. An element of soil is subjected to the normal
compressive stresses of 100 and 40kPa as
shown in Figure 2. Shear stresses are now
applied to the planes on which these stresses act.
What is the magnitude of the shear stress which
must be applied to those planes such that the
plane of major principal stress in the element is
horizontal?
Answer:
4. The stresses shown in Figure 3 are applied at
a point in a soil mass. Determine the angle
that the plane of major principal stress makes
with the x-axis.
Answer: