SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
MODULE- 49C
Sub-surface investigations- scope, drilling bore holes, sampling, penetration
tests, and plate load test.
1.
A plate load test was conducted in sand on a 300 mm diameter plate. If
the plate settlement was 5 mm at a pressure of 100 kPa, the settlement
(in mm) of a 5m × 8 m rectangular footing at the same pressure will be
(A) 9.4
(B) 18.6
(C) 12.7
[
)]
(D) 17.8
Ans:
=
= *
(
(
)+
= 17.8 mm
2.
The observed value of the standard penetration number (N) at 10m
depth of a silty sand deposit is 13. The unit weight of the soil is 16
kN/ . The N value after correcting for the presence of fines will be
(A) 12 (B) 13 (C) 14 (D) 15
Ans: (B) no correction for presence of fines
3.
In a plate load test conducted on cohesion-less soil, a 600 mm square
test plate settles by 15mm under a load intensity of 0.2 N/mm2. All
conditions remaining the same, settlement of a 1m square footing will
be
(a) Less than 15 mm
(b) Greater than 25 mm
(c) 15.60 mm
(d) 19.97 mm
Ans:
=
[
(
=
*
(
)]
)+
= 19.97 mm
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
4.
Match the items of the two lists and select the correct answer.
List I (Boring Methods)
P
Auger Boring
Q
Wash Boring
R
Percussion Drilling
S
Rotary Drilling
List II (Field Conditions)
1.
2.
3.
4.
Below water table in all soil types except hard soils
and rocks
Large diameter boreholes over 150 mm in size
Explorations for shallow foundations and highways
Bouldery and gravelly strata
Codes:
(a)
(b)
(c)
(d)
P
3
1
2
3
Q
1
2
3
1
R
4
4
4
2
S
2
3
1
4
Ans: (d)
5.
Match the items of List-I with List-II and select the correct answer.
List I
P. Modulus of subgrade reaction
Q. Relative density and strength
R. Skin friction and point bearing resistance
S. Elastic constants
1.
2.
3.
4.
5.
List II
Cyclic pile load test
Pressure meter test
Plate load test
Standard penetration test
Dynamic cone penetration test
Codes:
(a)
(b)
(c)
(d)
P
1
1
2
3
Q
3
2
5
4
Ans:
Plate load test
SPT
Cyclic pile load test
resistance.
Pressure meter test
JH ACADEMY
R
2
4
1
1
S
5
3
3
2
: modules of sub grade reaction
: Relative density and strength
: Skin friction and point bearing
: Elastic constants
2
SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
6.
In the context of collecting undisturbed soil samples of high quality
using a spoon sampler, following statements are made.
(I) Area ratio should be less than 10%.
(II) Clearance ratio should be less than 1%.
With reference to above statements, which of the following applies ?
(a)
(b)
(c)
(d)
Both the statements are true
Statement II is true but I is false
Statement I is true but II is false
Both the statement are false.
Ans: (a)
7.
During the subsurface investigations for design of foundations, a
standard penetration test was conducted at 4.5m below the ground
surface. The record of number of blows is given below
Penetration depth (cm)
No. of blows
0-7.5
3
7.5-15
3
15-22.5
6
22.5-30
6
30-37.5
8
37.5-45
7
Assuming the water table at ground level, soil as fine sand and
correction for overburden as 1.0, the corrected 'N' value for the soil
would be
(a)
(c)
18
21
(b)
(d)
19
33
Ans:
SPT value = number of blows for last 30 cm
= 6 + 6 + 8 + 7 = 27
Dilatancy correction = 15 + ½ (27 – 15)
= 15 + ½ 12 = 21
8.
The number of blows observed in a Standard Penetration Test (SPT) for
different penetration depths are given as follows
Penetration of sampler Number of blows
0-150 mm
6
150-300
8
300-450 mm
10
The observed N value is
(a) 8
(b) 14
(c) 18
(d) 24
Ans: 8 + 10 = 18
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
9.
A test plate 30cm x 30cm resting on a sand deposit settles by 10mm
under a certain loading intensity. A footing 150cm x 200cm resting on
the same sand deposit and loaded to the same load intensity settles by
(A) 2.0mm
(C) 3.02mm
(B) 27.8mm
(D) 50.0mm
Ans :
=
[
= 10*
(
(
)]
)+
= 27.8 mm
10. Dilatancy correction is required when a strata is
(A) Cohesive and saturated and also has N Value of SPT > 15
(B) Saturated silt/fine sand and N value of SPT < 10 after the
overburden correction
(C) Saturated silt/fine sand and N value of SPT >15 after the
overburden correction
(D) Coarse sand under dry condition and N value of SPT < 10 after the
overburden correction
Ans: (C)
11. A plate load test is carried out on a 300mm× 300mm plate placed at 2 m
below the ground level to determine the bearing capacity of a 2m× 2m
footing placed at same depth of 2m on a homogeneous sand deposit
extending 10m below ground. The ground water table is 3m below the
ground level. Which of the following factors does not require a
correction to the bearing capacity determined based on the load test?
(A) Absence of the overburden pressure during the test
(B) Size of the plate is much smaller than the footing size
(C) Influence of the ground water table
(D) Settlement is recorded only over a limited period of one or two days
Ans: (C)
Because plate and foundation both are in same level.
12. Consider the following properties for a soil sampler:
1. Area ratio should be low.
2. Cutting edge should be thick.
3. Inside clearance should be high.
4. Outside clearance should be low.
The properties necessary for a good quality soil sampler would include
(a) 1 and 4
(b) 1, 2 and 4
(c) 2, 3 and 4
(d) 1, 3 and 4
Ans: (a)
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
13. Consider the following statements: In subsoil exploration programs the
term “significant depth of exploration” is up to
1. The width of foundation
2. Twice the width of foundation
3. The depth where the additional stress intensity is less than 20% of
overburden pressure
4. The depth where the additional stress intensity is less than 10% of the
overburden pressure
5. Hard rock level
which of these statements is/are correct?
(a)1, 3 and 5
(c)1 and 4
(b)2, 3 and 5
(d)2 and 4
Ans; (d)
14. If the actual observed value of standard penetration resistance, N, is
greater than 15 in a fine sand layer below water table, then the
equivalent penetration resistance will be
(a)15 + *
+
(b) 15 - *
+
(c) 15 + *
+
(d) 15 + *
+
Ans: (c)
15. Match List-I (Field test) with List-II (Parameters measured) and select
the correct answer using the codes given below the lists:
List-I
A. Plate Load Test
B. Standard Penetration Test
C. Static Dutch Cone Penetration Test
D. Dynamic Penetration test
List-II
1. Total and frictional resistances
2. Load intensity and settlement values
3. NCD values
4. SPT values
Codes:
A
B
C
D
(a) 2
4
3
1
(b) 4
2
3
1
(c) 2
4
1
3
(d) 4
2
1
3
Ans: (c)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
16. In standard penetration test, the split spoon sampler is penetrated into
the soil stratum by giving blows from a drop weight whose weight (in
kg) and free fall (in cm) are, respectively
(a) 30 and 60
(b) 60 to 30
(c) 65 to 75
(d) 75 to 65
Ans: (c)
17. Assertion (A): In the case of sand deposits with uniform density, N
values are found to increase with depth.
Reason (R): Overburden pressure increases with depth below ground
level.
Codes:
(a)Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R in not a correct explanation of A
(c) A is true nut r is false
(d)A is false but R is true
Ans: (a)
18. A good quality undisturbed soil sample is one which is obtained using a
sampling tube having an area ratio of
(a) 8%
(b)16%
(c) 24%
(d) 32%
Ans: (a)
19. Which one of the following tests CANNOT be done without
undisturbed sampling?
(a) Shear strength of sand
(b) Shear strength of clay
(c) Determination of compaction parameters
(d) Atterberg limits
Ans: (b)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
20. Consider the following statements:
1. Dynamic cone penetration test for site investigation is based on the
principle that elastic shock waves travel in different materials at
different velocities.
2. Electrical resistivity method of subsurface investigation is capable of
detecting only the strata having different electrical resistivity
3. In-situ vane shear test is useful for determining the shear strength of
very soft soil and sensitive clays and is unsuitable for sandy soil.
Which of these statements is/are correct?
(a)1 and 2
(b)1 and 3
(c) 2 and 3
(d) 2 alone
Ans: (c)
21. The standard penetration resistance N of a granular deposit is found to
be 20. The soil can be classified approximately in terms of 𝜙 and
density index respectively as
(a) 200 and 10% for very loose condition
(b) 320 and 50% for medium condition
(c) 320 and 30% for loose condition
(d) 380 and 65% for dense condition
Ans: (d)
22. Match List-I (In-situ test) with List-II (Measurement) and select the
correct answer using codes given below the lists:
List-I
A. SPT test
B. Plate load test
C. Field vane shear test
D.CPT test
List-II
1. Penetration resistance (N value)
2. Load settlement data
3. Point resistance and skin friction
4. In situ shear strength
Codes:
A
B
C
D
(a)1
2
4
3
(b)1
2
3
4
(c)2
1
3
4
(d)2
1
4
3
Ans: (a)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
23. A soil sampler has inner and outer radii of 25 mm and 30 mm,
respectively. The area ratio of the sampler is
(a) 24%
(b) 34%
(c) 44%
(d) 54%
Ans:
= 0.44
i.e 44%
24. The correct sequence of the increasing order of the disturbance to soil
samples obtained from chunk, piston, spilt spoon and remoulded
sampler is
(a) Piston sampler, chunk sampler, split spoon sampler, remoulded
sampler
(b) Chunk sampler, piston sampler, split spoon sampler, remoulded
sampler
(c) Piston sampler, chunk sampler, remoulded sampler, split spoon
sampler
(d) Chunk sampler, piston sampler, remoulded sampler, split spoon
sampler
Ans: (b)
25. Match List-I(Sampler) with List-II (Use) and select the correct answer
using the codes given below the lists:
List-I
A. Split spoon sampler
B. Stationary piston sampler
C. Rotary sampler
D. Compressed air sampler
List-II
1. To obtain representative samples in all types of soil
2. To obtain undisturbed samples of sands below water table
3. To obtain undisturbed samples in clay and silts
4. To obtain approximately undisturbed samples of hard cemented
cohesive soils Codes:
A
B
C
D
a)
1
3
2
4
b)
3
1
4
2
c)
1
3
4
2
d)
3
1
2
4
Ans: (c)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
26. Consider the following statements:
1.The standard penetration test is a reliable method for measuring the
relative density of granular soils.
2. For a sand having the same relative density, N-values remain the
same at all depths.
3. For a sand having the same relative density, N-values are different at
different depths.
Which of these statements is/are correct?
(a) 1, 2 and 3
(b) 1 and 2
(c) 3 only
(d) 1 and 3
Ans: (b)
27. Match List-I (Type of exploration) with List-II(Soil profile) and select
the correct answer using the codes given below the lists:
List-I
A. Diamond core drilling
B. Uncased wash boring
C. Open pit excavation
D. Cased boring
List-II
1. Medium strong cohesive soils
2. Rocky formation
3. Soft cohesive soils and cohesion less soils. Exploration up to
relatively large depths 4.Exploration up to a shallow depth below
ground level
Codes:
a)
b)
c)
d)
A
B
C
D
4
2
4
2
3
1
1
3
2
4
2
4
1
3
3
1
Ans: (b)
28. Consider the following statements:
1. A recovery ratio of less than 1 implies that the soil has compressed.
2. A recovery ratio greater than 1 implies that the soil has swelled.
3. A recovery ratio of less than 1 implies that the soil has swelled.
4. A recovery ratio greater than 1 implies that the soil has compressed.
Which of these statements is/are correct?
(a) 1 and 2
(b) 1 only
(c) 3 and 4
(d) 4 only
Ans: (a)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
29. Consider the following statements:
1. Obtaining reliable properties of soil is very important in geotechnical
engineering. Chunk samples obtained from the field are the best for this
purpose.
2. Chunk
samples may easily be obtained at all depths below ground level and for
all types of soils.
3. Undisturbed soil samples are enclosed in rugged containers. As such,
they do not get disturbed easily during transportation and handling.
Which of these statements is/are correct?
(a) 1, 2 and 3
(b) 1 only
(c) 2 and 3
(d) 1 and 3
Ans: (d)
30. During a sampling operation, the drive sampler is advanced 600 mm
and the length of the sample recovered is 525 mm. What is the recovery
ratio of the sample?
(a) 0.125
(b) 0.140
(c) 0.875
(d) 0.143
Ans:
525/600=0.875
31. A sampling tube with a cutting edge is used for extracting the samples.
The sampling tube has the following dimensions:
Inner diameter of cutting edge= Dc
outer diameter of cutting edge = Dw
inner diameter of the sampling tube = Ds
Outer diameter of the sampling tube = Dt
What is the area ratio Ar of the sampling tube?
(a)
(b)
(c)
(d)
Ans: (a)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
32. Assertion (A): Estimate of settlement of foundations on sandy soils can
be done by using SPT values.
Reason (R): Sampling in cohesion less soil without disturbing the
structure is difficult.
Codes:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R in not a correct explanation of A
(c) A is true nut r is false
(d) A is false but R is true
Ans: (b)
33. Consider the following statements in respect of static cone penetration
test:
1. The cone used has an apex angle of 600 and base of 10 cm2.
2. This test give a continuous record of cone resistance. Which of these
statements is/are correct?
(a)1 only
(b)2 only
(c)Both 1 and 2
(d) neither 1 nor 2
Ans: (c)
34. On which of the following soils is the standard penetration test useful?
1. Cohesion less soils
2. Medium clays
3. Gravelly soils
4.Very stiff clays
Select the correct answer using the codes given below:
(a)1 only
(b)1 and 3
(c) 1 and 2
(d) 3 and 4
Ans: (c)
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
35. If an SPT test gave the average blow count of 32 in fine sand below
water table, then what is the corrected value of blow count?
(a) 22.1
(b) 23.5
(c) 24.2
(d) 24.8
Ans:
15 + ½ (30 – 15)
= 15 + 1/2 17
= 15 + 8.5 = 23.5
36. Consider the following statements:
1. The soil obtained from wash boring is a representative sample.
2. Recovery ratio will be high during drilling in sound rock.
3. Hollow stem augers are sometimes used to drill holes in silty sand.
Which of these statements is/are correct?
(a) 1 only
(b) 1 and 2
(c) 2 and 3
(d) 3 only
Ans: (c)
37. The standard penetration resistance value obtained in a deep deposit of
sand at a depth of 6.0 m was 28. The unit weight of sand is 18.0 KN/m2.
What is the corrected value of number of blows for overburden
pressure?
(a) 60
(b) 57
(c) 59
(d) 55
Ans:
= 28
= 55
JH ACADEMY
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SUB: GEOTECHNICAL ENGINEERING
MODULE-49C
38.
Match List-I with List-II and select the correct answer using the code
given below the lists:
List-I
A. Geophysical methods
B. SPT
C. DCPT
D. Piston-type sampler
List-II
1.Primarily for cohesive soils
2. Clays and silts
3.Reconnaissance covering large area and large depth
4. Suitable for sandy soils
Codes:
A
B
C
D
(a) 2
1
4
3
(b) 3
1
4
2
(c) 2
4
1
3
(d) 3
4
1
2
Ans: (d)
39. The observed N-value from a standard penetration test conducted in
saturated sandy strata is 30; the N-value corrected for Dilatancy may be
taken as
(a) 15
(c) 23
(b) 20
(d) 39
Ans:
15 + ½ (30 – 15)
= 15 + 7.5 = 22.5 say 23
40. Consider the following statements:
1. Standard penetration test is commonly used for cohesion less soils.
2. Standard penetration test results in respect of cohesion less soil are
correlated to its density index and friction angle.
3.Use of N-value not corrected for overburden pressure leads to highly
conservative design of footings at shallow depths.
Which of these statements are correct?
(a)1, 2 and 3
(b)1 and 2 only
(c) 2 and 3 only
(d)1 and 3 only
Ans: (a)
JH ACADEMY
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