B. 0.196
C. 5.10
D. 50.91
HYDRAULICS AND
GEOTECHNICAL
ENGINEERING
8. Determine the depth of the cut slope.
A. 30.89
B. 59.89
C. 36.81
D. 63.81
1. At two points 1 and 2 in a pipeline, the
velocities are V and 2V, respectively. Both
the points are at the same elevation. The
fluid density is ρ. The flow can be assumed
to be in compressible, inviscid, steady and
irrotational. The difference in pressures P1
and P2 at points 1 and 2 is
A. 0.5ρV2
B. 1.5ρV2
C. 2ρV2
D. 3ρV2
2. A saturated clay stratum draining both
at the top and bottom undergoes 50 percent
consolidation in 16 years under an applied
load. If an additional drainage layer were
present at the middle of the clay stratum,
50 percent consolidation would occur in
A. 16 years
B. 8 years
C. 4 years
D. 2 years
3. For a body completely submerged in a
fluid, the center of gravity (G) and center
of buoyancy (O) are known. The body is
considered to be in stable equilibrium if
A. O does not coincide with the center of
mass of the displace fluid
B. G coincide with the center of mass of
the displaced fluid
C. O lies above G
D. O lies below G
4. Soil derives its
capacity to resist
A. compression
B. torsion
C. tension
D. shear
strength
from
its
5. According to NSCP 2010 Sec. 307.3.1, when
concrete is used in metal-cased piles, the
specified compressive strength must have a
capacity of
A. not less than 17 MPa
B. not less than 20 MPa
C. not less than 25 MPa
D. not less than 30 MPa
9. Find the width in m of the channel at the
back of a suppressed weir using the
following data: H= 28.5 cm; d= 2.485 m; Q=
0.84 cu.m/sec. Consider the velocity of
approach and use the Francis formula.
A.
B.
C.
D.
2.01 m
3.0 m
1.75 m
4.2 m
10. A composite non prismatic 6 – m high
cylindrical tank has a frustum of a cone at
the bottom with the upper base diameter 3
m, 1.5-m-diameter at the bottom, and 5 m
high. The bottom contains 150 mm-diameter
sharp edged orifice with coefficient of
discharge of 0.65. If fully filled to the
top, determine the time to empty the tank
in minutes.
A. 589.5 s
B. 621.3 s
C. 408.8 s
D. 638.1 s
11. A conical tank 4 m diameter on top and
4.6 m tall has a 100–mm–diameter orifice at
its bottom for its outlet. Assume C = 0.65.
The tank is filled with 7500 liters of
water. How long will it take to drain the
content of the tank?
A. 2.88 min
B. 3.09 min
C. 3.62 min
D. 4.24 min
12. In the syringe as shown in the figure,
the drug has 900 kg/m 3 and an absolute
viscosity μ = 0.002 Pa–s. Neglecting head
loss in the larger cylinder. Determine the
force required to produce a flow of 0.4
mL/sec.
SITUATION (6-8). A cut is to be made in a
soil that has γ= 17 kN/m3, c= 40 kPa, φ=
20°. The side of the cut slope will make an
angle of 25° with the horizontal. Using a
factor of safety of 2,
6. Determine the stability number.
A. 0.0196
B. 0.196
C. 5.10
D. 50.91
7. Determine the stability factor.
A. 0.0196
A.
B.
C.
D.
9.03
7.56
8.19
10.3
kN
kN
kN
kN
13. During a flow of 500 liters/sec, the
gage pressure is +68 kPa in the horizontal
300 mm supply line of a water turbine and a
- 41 kPa at a 450 mm section of the draft
tube 2 m. below. Estimate the horsepower
output of the turbine under such conditions
assuming efficiency of 85%. Compute the
output horsepower of the turbine.
A. 63.2
B. 74.4
C. 99.7
D. 84.7
14. During a flow of 500 liters/sec, the
gage pressure is +68 kPa in the horizontal
300 mm supply line of a water turbine and a
- 41 kPa at a 450 mm section of the draft
tube 2 m. below. Estimate the horsepower
output of the turbine under such conditions
assuming efficiency of 85%. Compute the
horsepower input of the turbine.
A. 63.2
B. 74.4
C. 99.7
D. 84.7
15. A proposed embankment fill requires 8000
m3 of compacted soil. The void ratio of the
compacted fill is specified as 0.70. Four
borrow pits are available as described in
the following table, which lists the
respective void ratios of the soil and the
cost per cubic meter for moving the soil to
the proposed construction site. Make the
necessary calculations to select the pit
from which the soil should be bought to
minimize the cost. Assume Gs to be the same
at all pits.
A.
B.
C.
D.
Pit
Pit
Pit
Pit
characteristics of soil as follows: LI < 0
(brittle solid), LI < 1 (plastic), LI > 1
(liquid). What is the characteristic of
soil?
A. Brittle
B. Liquid
C. Dense
D. Plastic
19. An open rectangular tank mounted on a
truck is 4 m long, 2 m wide and 3 m high is
filled with water to a depth of 2.5 m. If
it is accelerated at 8 m/s 2, determine the
volume of water spilled.
A. 8.96 cu. m
B. 6.98 cu. m
C. 8.69 cu. m
D. 9.86 cu. m
20. Compute the speed in rpm of a 1 m
diameter and 3 m high cylinder full of water
which is rotated about its vertical axis
until 75% of its volume is spilled out.
A. 207.22 rpm
B. 210.34 rpm
C. 231.14 rpm
D. 209.56 rpm
21. SITUATION. The figure shows a layer of
soil in a tube that is 100 mm x 100 mm in
cross section. Water is supplied to maintain
a constant head difference of 400 mm across
the sample. The hydraulic conductivities of
the soils in the direction of flow is as
follows. Calculate the seepage velocity
through soil C in cm/sec.
A
B
C
D
16. For a granular soil, given dry unit
weight= 17.3 kN/m^3, relative density= 82%,
moisture content= 8% and Gs= 2.65. If emin =
0.44, what would be the dry unit weight in
the loosest state?
A. 14.54 kN/m 3
B. 13.21 kN/m 3
C. 13.65 kN/m 3
D. 14.23 kN/m 3
17. A saturated soil sample has a volume of
20 cm3 at its Liquid Limit. Given LL= 42%,
PL= 30%, SL= 17%, GS= 2.74. Find the minimum
volume the soil can attain.
A. 10.70 cm3
B. 19.97 cm3
C. 13.63 cm3
D. 14.77 cm3
18. A soil sample was determined in the
laboratory to have a liquid limit of 41% and
a plastic limit of 21.1%. If the water
content
is
30%,
the
following
A.
B.
C.
D.
0.00233
0.00384
0.00455
0.00146
22. A rectangular channel 6m wide has a
constant specific energy of 2.2m. Evaluate
the critical slope.
A. 0.00287
B. 0.00185
C. 0.00305
D. 0.00221
23. _________ is a proportionality constant
used to determine the flow velocity of water
through soils.
A. Seepage Velocity
B. Hydraulic Conductivity
C. Hydraulic Gradient
D. Seepage Flow
24. SITUATION. A 1-m wide curved gate
supports water as shown. The gate is from a
sector with radius 6 m and subtends 60°
angle. The gate is hinged at point A.
Evaluate the horizontal hydrostatic force
acting on a gate, in kN?
A.
B.
C.
D.
A.
B.
C.
D.
140
132
45
110
25.
(continuation)
Determine
how
far
horizontally from point O is the resultant
of the hydrostatic force located, in m.
A. 5.08
B. 5.12
C. 5.16
D. 5.20
26. (continuation) Evaluate the force P
required to hold the gate in place, in kN.
A. 31
B. 51
C. 39
D. 45
27. The curved surface AB shown in the
figure is a quarter of a circle of radius 5
ft.
Determine,
for
an
8-ft-length
perpendicular to the paper, the total
resultant force acting on surface AB.
6.47
6.35
5.42
4.24
m/s
m/s
m/s
m/s
29. A vertical cylindrical tank is 6 ft in
diameter and 10 ft high. Its sides are held
in position by means of two steel hoops, one
at the top and one at the bottom. The tank
is filled with water up to 9 ft high.
Determine the tensile force in the bottom
hoop.
A. 10614 lb
B. 15163 lb
C. 5307 lb
D. 7851 lb
30. A circular orifice 20-mm diameter is
located at the bottom of a tank 0.4 m2 in
plan area. At a given instant the head above
the orifice is 1.2 m. 307 seconds later the
head is reduced to 0.6 m. Calculate the
coefficient of Discharge.
A. 0.58
B. 0.60
C. 0.62
D. 0.64
31. A circular orifice 20-mm diameter is
located at the bottom of a tank 0.4 m2 in
plan area. At a given instant the head above
the orifice is 1.2 m. 307 seconds later the
head is reduced to 0.6m. Determine the time
for the head to fall from 1.2 m to 0.8 m.
A. 168 s
B. 174 s
C. 185 s
D. 193 s
A.
B.
C.
D.
6790
9802
6240
8918
lb
lb
lb
lb
28. The water tank in the figure is being
filled through section 1 at v 1 = 5 m/s and
through section 3 at Q3 = 0.012 m3/s. If
water level h is constant, determine the
exit velocity v2.
32. A short length of pipe suddenly enlarges
from 250 mm to 500 mm and convey 250 L/s of
water. If the pressure at the entrance of
the flow is 80 kPa, determine the energy
loss if the flow were to be reversed with a
contraction coefficient of 0.62?
A. 8.16m
B. 6.18m
C. 3.12m
D. 1.93m
33. Calculate the equivalent normal depth
of the most efficient trapezoidal section
corresponding
to
the
most
efficient
rectangular section having a normal depth
of 1.75 m assuming that both channels will
be constructed of the same material and laid
on the same slope.
A. 2.13m
B. 1.85m
C. 1.07m
D. 0.93m
34. A closed rectangular tank 4 m long, 2 m
wide, and 2 m high is filled with water to
a depth of 1.8 m. If the allowable force at
the rear wall of the tank is 200 kN, how
fast can it be accelerated horizontally?
A. 17.23 m/s2
B. 13.72 m/s2
C. 12.27 m/s2
D. 11.13 m/s2
35. An open cylindrical vessel having a
height equal to its diameter is half filled
with water and rotated about its own
vertical axis at a constant speed of 120
rpm. Evaluate its minimum diameter so that
there can be no liquid spilled.
A. 0.650 m
B. 0.368 m
C. 0.497 m
D. 0.551 m
36. A cut is to be made in a soil having
unit weight as 16.5 kN/m 3, cohesion of 28.75
kPa, and angle of friction of 15 degrees.
The side of the cut slope will make an angle
of 45 degrees with the horizontal. What
should be the depth of the cut slope that
will have a factor of safety FS= 3?
B. fine-grained soils
C. coarse-grained gravel
D. silts
38. A cut is to be made in a soil having
unit weight as 16.5 kN/m 3, cohesion of 28.75
kPa, and angle of friction of 15 degrees.
The side of the cut slope will make an angle
of 45 degrees with the horizontal. What
should be the depth of the cut slope that
will have a factor of safety FS=3?
A. 7.03
B. 9.65
C. 6.58
D. 5.65
39. From a hydrometer analysis to determine
particle sizes, it is found that 45 percent
of the sample consists of particles smaller
than 0.002 mm. The soil sample has a liquid
limit of 64% and plastic limit of 42%.
Determine the activity of the clay.
A. 0.68
B. 0.54
C. 0.32
D. 0.49
40. All samples from Atterberg’s Limit Tests
shall pass sieve __.
A. #10
B. #200
C. #40
D. #4
41. The cohesion and density of a soil are
2 ton/sq.m. and 2 ton/cu.m. respectively.
If the stability number is 0.1, considering
its safety factor as 2.00, determine the
safe height of the slope in meters.
A. 2.5
B. 10
C. 5
D. 7.5
42. Slope failure occurs only when the total
shear stress is
A. greater than the total shear strength
B. equal to the total shear strength
C. less than the total shear strength
D. none of the above
43. A 300 mm diameter test well penetrates
27 m below the static water table. After 24
hours of pumping at 69 liters/sec, the water
level in an observation well at a distance
of 95 m from the test well is lowered 0.5 m
and the other observation well at a distance
of 35 m from the test well, the water level
dropped by 1.1 m. Compute the coefficient
of permeability.
A. 76.20 m/day
B. 60.27 m/day
C. 67.20 m/day
D. 72.60 m/day
A.
B.
C.
D.
1594.26 kN
1413.20 kN
1673.23 kN
531.42 kN
37. Sieve analysis is meant for:
A. coarse-grained soils
44. A hydraulic jump occurs on a triangular
channel with 90 degrees vertex angle. The
depth before the jump is 2 m and the Froude
number is 1.67. Determine the power lost on
the hydraulic jump.
A. 27.71 kW
B. 20.92 kW
C. 13.24 kW
D. 28.2 kW
45. A sewer pipe, for which n=0.016, is laid
on a slope of 0.00015 and is to carry 3.5m 3/s
when the pipe flows at 80percent of full
depth. Determine the required diameter of
pipe.
A. 2.76 m
B. 3.5 m
C. 5.52 m
D. 1.75 m
46. A permeable soil layer that is underlain
by an impervious layer slopes at 5 degrees
to the horizontal and is 4 m thick measured
vertically.
If
the
coefficient
of
permeability
of
the
permeable
layer
k=0.005cm/sec,
determine
the
rate
of
seepage per meter width of permeable layer
in liters per hour.
A. 62.51 m
B. 56.62 m
C. 65.52 m
D. 52.26 m
47.
For
a
residential
building
construction, as a rule of thumb, OBO will
require
you
to
conduct
foundation
investigation for structures that are
_____.
A. 2-storey and up
B. 3-storey and up
C. 1-storey and up
D. 4-storey and up
48.
Evaluate
the
allowable
bearing
capacity, in kPa, of the soil for a square
footing 1.5 m wide when founded at a depth
of 1.2 m below the ground surface. Use
Section 304 of the National Structural Code
of the Philippines with a presumptive SBC
of 100 kPa.
A. 288 kPa
B. 277 kPa
C. 360 kPa
D. 300 kPa
49.
Evaluate
the
allowable
bearing
capacity, in kPa, of the soil for a square
footing 1.8 m wide when founded at a depth
of 1.5 m below the ground surface. Use
Section 304 of the National Structural Code
of the Philippines with a presumptive SBC
of 100 kPa.
A. 288 kPa
B. 330 kPa
C. 360 kPa
D. 300 kPa
50.
To
determine
the
volume
of
an
irregularly shaped object that weighs 300 N
in air, the engineer completely submerged
it in fresh water and observed that the
weight was reduced to 230 N. Evaluate the
volume of the object (m3).
A. 0.00741
B. 0.00714
C. 7.14
D. 7.41