INSTITUTE OF AERONAUTICAL ENGINEERING - · PDF file · 2015-04-17... P a g e...

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INSTITUTE OF AERONAUTICAL ENGINEERING Dundigal, Hyderabad - 500 043

CIVIL ENGINEERING

QUESTION BANK

Course Name : GEOTECHNICAL ENGINEERING II

Course Code : 56004

Class : III - B. Tech

Branch : Civil Engineering

Year : 2014 – 2015

Course Coordinator : Ms Y. Shireesha

Course Faculty : Ms Y. Shireesha

OBJECTIVES To meet the challenge of ensuring excellence in engineering education, the issue of quality needs to be addressed, debated and taken forward in a systematic manner. Accreditation is the principal means of quality assurance in higher education. The major emphasis of accreditation process is to measure the outcomes of the program that is being accredited. In line with this, Faculty of Institute of Aeronautical Engineering, Hyderabad has taken a lead in incorporating philosophy of outcome based education in the process of problem solving and career development. So, all students of the institute should understand the depth and approach of course to be taught through this question bank, which will enhance learner’s learning process. 1. Group - A (Short Answer Questions)

S. No QUESTION Blooms Taxonomy

Level Course

Outcome

UNIT-I SOIL EXPLORATION

1 Define soil exploration. Discuss the need of soil exploration. Remember a

2 Differentiate between undisturbed and disturbed soil samplers. Understand a

3 Describe the various steps involved in soil exploration planning. Remember a

4 Two samplers have area ratios of 10.9% and 21%. Which one of these is

recommended for better soil sampling and why? Analyze a

5 Explain the use of split spoon sampler.

Understand a

6 Write a short note on geophysical exploration using electrical resistivity. Remember a

7 What are the merits and demerits of wash boring method? Remember a

8 What are the merits and demerits of split spoon sampler? Remember a

9 Sketch a split spoon sampler and explain its parts in brief. Understand a

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Outcome

10 What is N-value of standard penetration test? Remember b

UNIT-II SLOPE STABILITY

1 Differentiate finite and infinite earth slopes with suitable examples. Understand c

2 Discuss classification of slopes. Remember c

3 What are the causes of failure of slopes? Analyze c

4 Compare the Swedish arc circle method with method of slices. Analyze c

5 Write brief notes on Taylor’s stability number. Understand c

6

Under what conditions (i) a base failure and (ii) a toe failure are expected?

Explain. Analyze c

7 Discuss the basic assumptions made in the stability analysis of slopes. Remember c

8

Describe a suitable method of stability analysis of slopes in purely saturated

cohesive soil. Analyze c

9 Describe a suitable method of stability analysis of slopes in cohesion less soil. Analyze c

10 Explain method of slices for stability analysis of slopes. Remember c

UNIT-III EARTH PRESSURE THEORIES

1 Explain the earth pressure in active, passive and at rest conditions. Understand d

2

From the plastic equilibrium equation, show that the cohesion of backfill

reduces the active earth pressure and increases the passive earth pressure. Analyze d

3 What are the assumptions made in Coulomb’s theory? Remember d

4

Compare the Rankine’s and Coulomb’s theories for computation of earth

pressure and suggest the suitability of these methods. Analyze d

5 What are the assumptions made in Rankine’s theory of earth pressure? Remember d

6 What is the effect of submergence on active and passive earth pressures? Analyze d

7 Write notes on Rankine’s earth pressure theory. Understand d

8 Write notes on Culmann’s graphical method. Understand d

9 Distinguish between active and passive pressures. Understand d

10 Write notes on Coulomb’s earth pressure theory.

Remember d

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Level Course

Outcome

UNIT-IV RETAINING WALLS

1 Describe gravity and semi-gravity retaining walls.

Understand e

2 Discuss the stability of retaining walls against overturning.

Analyze e

3 Discuss the stability of retaining walls against sliding.

Analyze e

4 Discuss the stability of retaining walls against bearing capacity.

Analyze e

5 Explain the significance of weep holes in performance of retaining walls.

Understand e

6 Describe cantilever retaining wall. Remember e

7 Describe counterfort and buttress retaining walls Remember e

8 Distinguish between counterforts and buttress retaining walls.

Understand e

9 Distinguish between gravity and semi-gravity retaining walls. Understand e

10 Describe the various methods used for draining backfills. Remember e

UNIT-V SHALLOW FOUNDATIONS- BEARING CAPACITY CRITERIA

1 Distinguish between shallow and deep foundations.

Understand f

2 Enumerate the various types of shallow foundations.

Understand f

3 What are the various types of spread footings? Explain with diagrams.

Analyze f

4 Make a note on combined footing and its types.

Remember f

5 What is strip footing and when is it preferred?

Understand f

6 What is raft footing? What are its types? Remember f

7 When are raft foundations preferred? Understand f

8 What are the assumptions made in Terzaghi’s bearing capacity theory?

Remember f

9 Enumerate the similarities between Terzaghi’s and Meyerhof’s bearing capacity theories.

Understand f

10 Enumerate the differences between Terzaghi’s and Meyerhof’s bearing

capacity theories. Understand f

UNIT-VI SHALLOW FOUNDATIONS - SETTLEMENT CRITERIA

1 What are the various types of settlements in foundations?

Understand g

2 What are the types of settlements caused due to loads?

Understand g

3

What are the types of settlements which are caused due to reasons other

than loads? Understand g

4 Differentiate between uniform settlement and differential settlement.

Analyze g

5 What are the objectives of proportioning of footing?

Remember g

6 What is the procedure for proportioning of footing? Analyze g

7 Make a note on plate load test. Understand g

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8 Make a note on initial settlement.

Analyze g

9 Make a note on consolidation settlement. Analyze g

10 Make a note on secondary settlement. Analyze g

UNIT-VII PILE FOUNDATION

1 Define pile foundation. When are pile foundations preferred? Analyze h

2 Classify piles based on their method of installation.

Understand h

3 Classify piles based on their type of application.

Understand h

4 What are the various classifications of piles?

Understand h

5 Explain the settlement analysis of piles in short.

Analyze h

6 Write a note on dynamic formula of piles. Remember h

7 Make a note on static method for load carrying capacity of piles. Remember h

8 Write Hiley’s formula for load carrying capacity of piles. Remember h

9 Write Engineering News Record formula for load carrying capacity of piles. Remember h

10 Write Danish formula for load carrying capacity of piles. Remember h

UNIT-VIII WELL FOUNDATION

1 What are the types of caisson foundations? Remember h

2 Write a note on open caisson foundation.

Remember h

3 Write a note on pneumatic caisson foundation.

Remember h

4 Write a note on floating caisson foundation.

Remember h

5 With neat sketch, explain the components of pneumatic caisson.

Analyze h

6 With neat sketch, explain the components of open caisson Analyze h

7 What is the procedure for sinking of pneumatic caisson? Analyze h

8 Discuss the various types of shapes of well foundations. Remember h

9 Discuss the effect of impact and longitudinal loads on well foundations. Analyze h

10 Discuss the effect of water and earth pressure on well foundations. Analyze h

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2. Group - II (Long Answer Questions)

S. No Question Blooms

Taxonomy Level Course

outcome


1 Explain the various methods of boring adopted in soil investigation.

Remember a

2 Describe open driven, piston and rotary samplers with neat sketches.

Remember a

3

Write a detailed note on the test setup and procedure of standard

penetration test including the corrections to be applied. Understand b

4

Explain in detail the test setup and procedure of plate load test as per

IS: 1885 including the analysis of data and its limitations. Understand b

5

Explain various methods of soil exploration and comment on suitability

of each of them. Remember a

6

Why are undisturbed samples required? Describe any one procedure of

obtaining undisturbed samples for a multi-storied building project. Analyze a

7

How do you find the relative density from ‘N-value’? Explain the various

corrections to be applied to the observed value of N. Analyze b

8

Explain and discuss the various factors that help decide the number and

depth of bore holes required for subsoil exploration. Analyze

a

9

Under what circumstances are geophysical methods used in

exploration? Discuss the usefulness of a dynamic cone penetration test

and its limitations. Analyze

a

10

Explain the following:

i. Factors involved in soil exploration. ii. Elements on which soil exploration depends.

Remember a


1

Discuss various types of failure of slopes and explain the necessary

conditions for each of them to occur. Analyze c

2 Discuss the stability analysis of infinite slopes.

Understand c

3

Explain Bishop’s simplified method for determination of factor of safety

of a finite slope. Understand c

4

Explain stability of earthen dam in full reservoir and sudden draw down

condition. Analyze c

5

Explain Swedish slip circle method and derive the factor of safety for a

slope in cohesive soils Analyze c

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6

Explain the method of slices for estimation of factor of safety of finite

slopes. Also, obtain the expression for factor of safety of a c – φ. Analyze c

7 Explain stability of earthen dam in full reservoir condition.

Analyze c

8 Explain Taylor’s stability number and the procedure of its use.

Analyze c

9 Explain the method of slices for estimation of factor of safety of finite slopes.

Analyze c

10 Obtain the expression for factor of safety of a c – φ soil using method of slices.

Remember c


1

What are the assumptions made in Rankine’s theory of earth pressure?

Derive the expression for active and passive earth pressure. Remember d

2

Explain the procedure for computation of active earth pressure in case

of backfill with its top inclined to horizontal. Analyze d

3 Explain Culmann’s graphical method for computation of earth pressure.

Remember d

4 Derive the Rankine’s earth pressure in cohesive soils.

Analyze d

5

What are the assumptions made in Coulomb’s theory of earth pressure?

Derive the expression for active and passive earth pressure. Remember d

6 Derive a general expression for active earth pressure by the Coulomb theory behind a vertical wall due to cohesion less soil with a level surface.

Analyze d

7

Describe Culmann’s graphical method of finding earth pressure and explain the classical theory of earth pressure on which this procedure is based. Explain how surcharge will affect earth pressure in active and passive states.

Analyze

d

8

With the aid of Mohr’s circle diagram explain what is means by active and passive Rankine states in cohesion less soil with a horizontal surface. Hence obtain an expression for the intensity of active earth pressure behind a vertical wall and explain why for this condition there is an implied assumption of smooth wall.

Analyze d

9 Describe the Coulomb’s theory for determining active earth pressure and evaluate the assumptions. Discuss the advantages.

Remember d

10

Write notes on: (a) Rankine earth pressure theory. (b) Culmann method. (c) Coefficient of passive earth pressure.

Remember d


1 Describe the various types of retaining walls.

Remember e

2 Discuss the stability of retaining walls against overturning.

Analyze e

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3

Explain the procedure of recomputation of pressure when tension is

present at base. Understand e

4 Describe the various methods used for drainage of the backfill.

Remember e

5 Discuss the stability of retaining walls against sliding.

Analyze e

6 Discuss the stability of retaining walls against bearing capacity.

Analyze e


1 What is a strip footing? When is it preferred?

Understand f

2 Explain spread footing with detailed sketch.

Remember f

3 Explain combined footing in detail with sketch.

Remember f

4 What are the types of deep foundations? Explain with sketches.

Remember f

5 Make a note on raft foundation. When is it preferred?

Understand f

6

State and explain the assumptions in Terzaghi’s bearing capacity

theory. Remember f

7 Derive the equation for Terzaghi’s bearing capacity theory. Analyze f

8 Discuss the IS code method for net ultimate bearing capacity.

Understand f

9

Write the expressions for Ultimate bearing capacity of soil for strip

footing for local shear failure. Also derive its net ultimate bearing

capacity and factor of safety. Remember

f

10

Make a note on Meyerhof and Skempton method for safe bearing

capacity. Remember f

UNIT-VI SHALLOW FOUNDATIONS - SETTLEMENT CRITERIA

1 What are the types of foundation settlements?

Remember g

2 Explain the procedure for plate load test in detail.

Analyze g

3

Differentiate between total settlement and differential settlement.

What are the harmful effects of differential settlement on structures?

What are the possible remedial measures? Analyze

g

4

How does the construction period affect the time-rate of settlement of

a structure? What is the effective loading period? Analyze g

5 Make a note on rigidity of structure and horizontal drainage and its Analyze g

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effect on foundation.


1

Explain the function of pile foundation and show how the bearing

capacity of the foundation can be estimated. Analyze h

2 Write brief critical notes on the bearing capacity of piles.

Remember h

3

Distinguish between driven and bored piles. Explain why the settlement of a pile foundation (pile group) will be many times that of a single pile even though the load per pile on both cases is maintained the same.

Analyze h

4 Give a method to determine the bearing capacity of a pile in clay soil. What is group effect and how will you estimate the capacity of a pile group in clay ?

Analyze h

5 What are the various methods used for determining the capacity of (i) a driven pile and (ii) a cast-in-situ pile?

Remember h

6 What is the basis on which the dynamic formulae are derived? Mention two well known dynamic formulae and explain the symbols involved.

Analyze h

7 Classify piles based on their method of installation, application and load transfer.

Understand h

8

Discuss about the materials used for pile foundations and their

properties. Evaluate h

9

Describe the static method for determining the load carrying capacity

of piles. Evaluate h

10 Explain the settlement analysis for pile groups. Analyze h


1

Describe various types of caisson foundations and comment on their

suitability. Understand h

2 Explain in detail the procedure of sinking of well foundations.

Analyze h

3

Describe the component parts of a Pneumatic Caisson with a neat sketch. What are the advantages and disadvantages of a Pneumatic Caisson when compared with other types?

Remember h

4 What is a ‘Floating Caisson’? How is its stability checked? What are the merits and demerits of a Floating Caisson when compared with other types?

Remember h

5 Discuss the various kinds of forces likely to act on a well foundation. Remember h

6 Discuss the different shapes of Cross-sections of wells used in practice, giving the merits and demerits of each.

Remember h

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7 Sketch and describe the various components of a well foundation, indicating the function of each.

Understand h

8 Discuss the construction aspects of Well Foundations. What are ‘Tilts and Shifts’? What are the remedial measures to control these?

Understand h

9 Discuss the design procedure of caisson foundation.

Analyze h

10

Explain an ‘Open Caisson’ with a neat sketch showing all the component parts. How is the load-carrying capacity of an Open Caisson determined? What are the merits and demerits of an Open Caisson?

Remember h

3. Group - III (Analytical Questions)

S.No QUESTIONS Blooms Taxonomy

Level Course

outcome


1

A SPT was conducted in a dense sand deposit of 22m, and a value of 48 was

observed for N. the density of the sand was 15 kN/m2. What is the value of N,

corrected for overburden pressure? Apply

a

2

Compute the area ratio of a thin walled tube samples having an external

diameter of 6cm and a wall thickness of 2.25mm. Do you recommend the

sampler for obtaining undisturbed soil samplers? Why? Apply

a

3

A SPT is conducted in fine sand below water table and a value of 25 is obtained

for N. What is the corrected value of N? Apply a

4

A SPT was conducted in a dense sand deposit at a depth of 22m, and a value of

48 was observed for N. the density of the sand was 15kN/m2. What is the value

of N, corrected for overburden pressure? Apply

a

5

An N-value of 35 was obtained for a fine sand below water table. What is the

corrected value of N? Apply a

6

A SPT was performed at a depth of 20m in a dense sand deposit with a unit

weight of 17.5 kN/m2. If the observed N-value is 48, what is the N-value

corrected for overburden? Apply

a

7

A SPT is conducted in fine sand below water table and a value of 30 is obtained

for N. What is the corrected value of N? Apply a

8

An N-value of 40 was obtained for fine sand below water table. What is the

corrected value of N? Apply a

9

Compute the area ratio of a thin walled tube samples having an external

diameter of 8cm and a wall thickness of 3.25mm. Do you recommend the

sampler for obtaining undisturbed soil samplers? Why?

Apply

a

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10

A SPT was conducted in a dense sand deposit at a depth of 20m, and a value of

48 was observed for N. the density of the sand was 17kN/m2. What is the value

of N, corrected for overburden pressure? Apply

a


1

It is proposed to construct a highway embankment using a c-φ soil having c = 20

kPa, φ = 10°, γ = 17 kN/m3. Determine the critical height up to which the

embankment can be built with an inclination of 29° with a factor of safety of

1.50. Given the Taylor’s stability number for these conditions as 0.0737.

Apply c

2

Find factor of safety of a slope of infinite extent having a slope angle of 25°. The

slope is made of cohesion less soil with φ = 30°. Also analyze the slope if it is

made of clay having c’ = 30 kN/m2, φ’ = 20°, e = 0.65 and Gs= 2.7 and under the

following conditions:

i. When soil is dry

ii. When water seeps parallel to the surface of the slope

iii. When the slope is submerged.

Apply c

3

An excavation has to be made with an inclination of 40° in a soil with c’ = 40

kPa, φ’ = 10°, γ = 18 kN/m3. What is the maximum height of the slope with a

factor of safety of 2.01. The Taylor’s stability number for the above condition is

given as 0.097.

Apply c

4

An embankment 10m high is inclined at an angle of 36° to the horizontal. A

stability analysis by the method of slices gives the following forces per running

meter:

Σ shearing forces = 450 kN

Σ normal forces = 900 kN

Σ neutral forces = 216 kN

The length of the failure arc is 27m. Laboratory tests on the soil indicate the

effective values c’ and φ’ as 20 kN/m2 and 18° respectively. Determine the

factor of safety of the slope with respect to

a) Shearing strength b) Cohesion

Apply c

5

An embankment is inclined at an angle of 35° and its height is 15m. The angle of

shearing resistance is 15° and the cohesion intercept is 200 kN/m2. The unit

weight of soil is 18 kN/m3. If Taylor’s stability number is 0.06, find the factor of

safety with respect to cohesion.

Apply c

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outcome

6

Find factor of safety of a slope of infinite extent having a slope angle of 20°. The

slope is made of cohesion less soil with φ = 30°. Also analyze the slope if it is

made of clay having c’ = 35 kN/m2, φ’ = 25°, e = 0.60 and Gs= 2.7 and under the

following conditions:

a) When soil is dry b) When water seeps parallel to the surface of the slope c) When the slope is submerged.

Apply c

7

An excavation has to be made with an inclination of 45° in a soil with c’ = 30 kPa, φ’ = 15°, γ = 17 kN/m

3. What is the maximum height of the slope with a

factor of safety of 2. The Taylor’s stability number for the above condition is given as 0.097.

Apply c

8

An embankment 10m high is inclined at an angle of 36° to the horizontal. A

stability analysis by the method of slices gives the following forces per running

meter:

Σ shearing forces = 450 kN

Σ normal forces = 900 kN

Σ neutral forces = 216 kN

The length of the failure arc is 27m. Laboratory tests on the soil indicate the

effective values c’ and φ’ as 20 kN/m2 and 18° respectively. Determine the

factor of safety of the slope with respect to

a) Shearing strength b) Cohesion

Apply c

9

An embankment is inclined at an angle of 35° and its height is 10m. The angle of

shearing resistance is 20° and the cohesion intercept is 200 kN/m2. The unit

weight of soil is 17 kN/m3. If Taylor’s stability number is 0.06, find the factor of

safety with respect to cohesion.

Apply c

10

It is proposed to construct a highway embankment using a c-ϕ soil having c = 25

kPa, φ = 20°, γ = 17 kN/m3. Determine the critical height up to which the

embankment can be built with an inclination of 30° with a factor of safety of

1.50. Given the Taylor’s stability number for these conditions as 0.0737.

Apply c


1

A 9m high retaining wall is supporting a backfill consisting of two types of soils.

The water table is located at a depth of 5m below the top. The properties of soil

from 0 to 3m include c = 0kN/m2; φ = 33°; γ = 17 kN/m

3 and those for soil from

3m to 9m include c = 0kN/m2; φ = 40°; γ = 18.50kN/m

3; γsub = 20.50 kN/m

3.Plot

the distribution of active and passive earth pressure and determine the

magnitude and point of application of total active and passive earth pressure

acting on the retaining wall.

Apply d

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outcome

2

A 8m high retaining wall is supporting a c – φ backfill having c = 40 kN/m2; φ =

24°; γ = 18.50 kN/m3. Plot the distribution of active and passive earth pressure

and determine the magnitude and point of application of total active and

passive earth pressure acting on the retaining wall.

Apply d

3



from 0 to 4m include c = 30kN/m2; φ = 30°; γ= 17kN/m


4m to 10m include c = 10kN/m2; φ = 40°; γ = 18.50 kN/m

3; γsat = 20.50

kN/m3.Plot the distribution of active and passive earth pressure and determine

the magnitude and point of application of total active and passive earth

pressure acting on the retaining wall.

Apply d

4


The water table is located at a depth of 6 m below the top. The properties of

soil from 0 to 3m include c = 0kN/m2; φ = 30°; γ = 20kN/m

3 and those for soil

from 3m to 9m include c = 0kN/m2; φ = 40°; γ = 24kN/m

3; γsub = 20.50

kN/m3.Plot the distribution of active and passive earth pressure and determine

the magnitude and point of application of total active and passive earth

pressure acting on the retaining wall.

Apply d

5

A 8m high retaining wall is supporting a c – φ backfill having c = 30kN/m2; φ =

24°; γ = 18kN/m3. Plot the distribution of active and passive earth pressure and

determine the magnitude and point of application of total active and passive

earth pressure acting on the retaining wall.

Apply d

6



from 0 to 4m include c = 30kN/m2; φ = 30°; γ= 17kN/m


4m to 10m include c = 15kN/m2; φ = 40°; γ = 20 kN/m

3; γsat = 20.50 kN/m

3.Plot

the distribution of active and passive earth pressure and determine the

magnitude and point of application of total active and passive earth pressure

acting on the retaining wall.

Apply d

7

A 10m high retaining wall is supporting a backfill consisting of two types of soils. The water table is located at a depth of 6m below the top. The properties of soil from 0 to 4m include c = 30kN/m

2; φ = 30°; γ= 20kN/m


4m to 10m include c = 15kN/m2; φ = 35°; γ = 20 kN/m

3; γsat = 20.5 kN/m

3.Plot

the distribution of active and passive earth pressure and determine the magnitude and point of application of total active and passive earth pressure acting on the retaining wall.

Apply d

8

A 8m high retaining wall is supporting a c – φ backfill having c = 50 kN/m2; φ =

25°; γ = 19 kN/m3. Plot the distribution of active and passive earth pressure and

determine the magnitude and point of application of total active and passive

earth pressure acting on the retaining wall.

Apply d

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9

A masonry retaining wall with vertical back has to retain a backfill of 6m height

behind it. The ground level is horizontal at the top and the water table is upto

the top of backfill. Assume unit saturated weight of backfill soil = 20kN/m3, c =

0, φ = 40°. Calculate the horizontal earth pressure on wall if wall moves away

from the backfill.

Apply d

10

A masonry retaining wall with vertical back has to retain a backfill of 6m height

behind it. The ground level is horizontal at the top and the water table is upto

the top of backfill. Assume unit saturated weight of backfill soil = 19kN/m3, c =

0, φ = 30°. Calculate the horizontal earth pressure on wall if wall moves towards

the backfill.

Apply d


1

A trapezoidal masonry retaining wall 1 m wide at top and 3 m wide at its bottom is 4 m high. The vertical face is retaining soil (φ = 30°) at a surcharge angle of 20° with the horizontal. Determine the maximum and minimum intensities of pressure at the base of the retaining wall. Unit weights of soil and masonry are 20kN/m

3 and 24 kN/m

3 respectively. Assuming the coefficient of friction at the

base of the wall as 0.45, determine the factor of safety against sliding. Also determine the factor of safety against overturning.

Apply e

2

A trapezoidal gravity retaining wall of height 6m with top and bottom widths as

0.45m &1.20m respectively is constructed in RCC with a unit weight of 25kN/m3.

Its bottom is resting 2m below the GL on soil having c = 0kN/m2; φ = 36°; γ = 18

kN/m3; the friction angle is 2/3 of φ. The allowable bearing capacity of the soil

for this case is found to be 200kN/m2. The wall is supporting the 4m thick

backfill above GL made of soil having c = 0kN/m2; φ = 30°; γ = 17.50 kN/m

3.

Analyze the stability of wall against overturning, sliding and bearing capacity.

Apply e

3

Design a gravity retaining wall of height 3m with uniform thickness (i.e.

rectangular in cross section) constructed in RRM with a unit weight of 24kN/m3.

The average properties of soil from top to bottom of wall include c = 0kN/m2; φ

= 36°; γ = 18kN/m3; the friction angle is 2/3 of φ. The allowable bearing capacity

of the soil for this case is found to be 200kN/m2. Analyze the stability of the wall

against overturning, sliding and bearing capacity.

Apply e

4

A gravity retaining wall of height 3 m with uniform thickness (i.e rectangular in

cross section) of 1.20m is constructed in RRM with a unit weight of 24kN/m3.

The average properties of soil from top to bottom of wall includes c = 0 kN/m2;

φ = 30°. Analyze the stability of wall against overturning when the entire backfill

is

i. Moist with a unit weight of 18kN/m3

ii. Submerged(consider the saturated unit weight in submerged conditions as 9.80kN/m

3)

Apply e

5

A gravity retaining wall of height 3 m with uniform thickness(i.e rectangular in

cross section)of 1.20m is constructed in RRM with a unit weight of 24kN/m3.The

average properties of soil from top to bottom of wall includes c = 0 kN/m2; φ =

Apply e

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outcome

30°. Subsequently, 1m high fill is placed on top of the existing backfill after

constructing a 0.60m thick wall above the existing wall matching with the

backfill side face of wall(i.e the offset is provided on the otherside of backfill).

Analyze the stability of wall against overturning before and after raising the

height of backfill.

6

A trapezoidal masonry retaining wall 1 m wide at top and 3 m wide at its bottom is 4 m high. The vertical face is retaining soil (ϕ= 30°) at a surcharge

angle of 20° with the horizontal. Determine the maximum and minimum

intensities of pressure at the base of the retaining wall. Unit weights of soil and

masonary are 20 kN/m3

and 24 kN/m3

respectively. Assuming the coefficient of

friction at the base of the wall as 0.45, determine the factor of safety against

sliding. Also determine the factor of safety against overturning.

Apply e

7

A trapezoidal gravity retaining wall of height 6m with top and bottom widths as 0.45m & 1.20m respectively is constructed in RCC with a unit weight of 25kN/m

3. Its bottom is resting 2m below the GL on soil having c = 0kN/m

2; φ =

36°; γ = 18 kN/m3; the friction angle is 2/3 of φ. The allowable bearing capacity

of the soil for this case is found to be 200kN/m2. The wall is supporting the 4m

thick backfill above GL made of soil having c = 0kN/m2; φ = 30°; γ = 17.50 kN/m

3.

Analyze the stability of wall against overturning, sliding and bearing capacity.

Apply e

8

Design a gravity retaining wall of height 3m with uniform thickness (i.e

rectangular in cross section) constructed in RRM with a unit weight of 24kN/m3.

The average properties of soil from top to bottom of wall include c = 0kN/m2; φ

= 36°; γ = 18kN/m3; the friction angle is 2/3 of φ. The allowable bearing capacity

of the soil for this case is found to be 200kN/m2. Analyze the stability of the wall

against overturning, sliding and bearing capacity.

Apply e

9

A gravity retaining wall of height 3 m with uniform thickness(i.e rectangular in

cross section)of 1.20m is constructed in RRM with a unit weight of 24kN/m3.


φ = 30°. Analyze the stability of wall against overturning when the entire backfill

is

i. Moist with a unit weight of 18kN/m3

ii. Submerged(consider the saturated unit weight in submerged conditions as 9.80kN/m

3)

Apply e

10

A gravity retaining wall of height 3 m with uniform thickness (i.e. rectangular in

cross section)of 1.20m is constructed in RRM with a unit weight of 24kN/m3.


φ = 30°. Subsequently, 1m high fill is placed on top of the existing backfill after

constructing a 0.60m thick wall above the existing wall matching with the

backfill side face of wall (i.e. the offset is provided on the other side of backfill).

Analyze the stability of wall against overturning before and after raising the

height of backfill.

Apply e

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1 Design a strip footing for load bearing wall transmitting a force of 200 kN/m proposed to be laid at a depth of 1.50 m below the G.L on a c-φ soil with c =40 kPa and φ=20° , γ=17 kN/m

3. Given NC=11.80, Nq=3.90, Nγ=1.70.

Apply f

2

A 2m wide square footing is laid at a depth of 1.2 m below the GL on a C-φ soil

with c=40 kPa and φ=20°, γ=17kN/m3. Given NC=11.80. Nq=3.90, Nγ=1.70. Using

Terzaghi’s theory, compute the ultimate bearing capacity (q6) when the GWT is,

I. 5 m below G.L

II. At G.L.

III. 2 m below G.L

Assume the change in shear parameter due to situation is negligible.

Apply f

3

Determine the ultimate bearing capacity of a 4 m dia circular footing as shown

below? Apply f

4

It is proposed to lay a suitable type of foundation at a depth of 1.5 m below the

ground level on soil a c-φ soil with c =30 KPa and φ =250 , γ = 17.50 kN/m3.

Given NC’ =14.80, Nq’ =5.60 , Nγ’ = 3.20. Estimate the ultimate bearing capacity

of a

I. 2 m wide strip footing

II. 2 m wide square footing

III. 2 m wide circular footing.

Comment on the results.

Apply f

5 Design a strip footing for load bearing wall transmitting a force of 300 kN/m proposed to be laid at a depth of 2 m below the G.L on a c-φ soil with c =40 kPa and φ=20° , γ=17 kN/m

3. Given NC=11.80, Nq=3.90, Nγ=1.70.

Apply f

6




I. 5 m below G.L

II. At G.L.

III. 2 m below G.L

Assume the change in shear parameter due to situation is negligible.

Apply f

7 Determine the ultimate bearing capacity of a 2 m dia circular footing as shown below?

Apply f

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8




of a





Apply f

9




i. 4 m below G.L ii. At G.L.

iii. 2 m below G.L Assume the change in shear parameter due to situation is negligible.

Apply f

10




of a





Apply f

UNIT-VI SHALLOW FOUNDATIONS- SETTLEMENT CRITERIA

1

Determine the total settlement of the foundation, for the condition given below, Ground level /GWT(+)0.00m Sand with γsat =20.50 kN /cum 2 wide square transmitting a contact pressure of 320 kPa Foundation level (-2.00m) Fully saturated compressible clay γsa=21.00 kN/m

3 , L.L = 108%, e0=1.05, µ =0.28 , ES =19500 kPa

2(-5.00m)IW = 1.05

Massive sheet rock Adopt distribution of stress as per 2V to 1H rule. Neglect the secondary consolidation settlement

Apply g

2 Determine the total settlement of the foundation, for the conditions given Apply g

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Level Course

outcome

below:

Ground Level/GWT(+)0.00 m

Sand with γsat =20.00kN/cum

2.5m wide square transmitting a contact pressure of 350 kPa

Foundation level (-2.00)

Fully saturated compressible clay

γsat =21.50 kN/m3

, L.L =98% , e0 = 1.00, µ = 0.24, Es =18500kN/m2

(-6.00m)IW =1.05

Massive sheet rock

Adopt distribution of stress as 2V to 1H rule. Neglect the secondary

consolidation settlement

3

Determine the total settlement of the foundation, for the conditions given

below:Ground Level/GWT(+)0.00 m

Sand with γsat =20.00kN/m3

2 m wide square transmitting a contact pressure of 120 kPa



γsat =20kN/cum, L.L =110% , e0 = 1.20, µ = 0.20, Es =19500kN/m2

(-5.00m)IW =1.05

Massive sheet rock

Adopt distribution of stress as per 2V to 1H rule. Neglect the secondary


Apply g

4

Determine the total settlement of the foundation, for the condition given

below,

Ground level /GWT(+)0.00m

Sand with γsat =20.50 kN /cum

2 wide square transmitting a contact pressure of 320 kPa

Foundation level (-2.00m)

Apply g

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γsa=21.00 Kn/m3

, L.L = 108%, e0=1.05, µ =0.28 , ES =19500 kPa2 (-5.00m)IW = 1.05

Massive sheet rock



5

Determine the total settlement of the foundation, for the conditions given below:






γsat =21.50 kN/m3

, L.L =98% , e0 = 1.00, µ = 0.24, Es =18500kN/m2

(-6.00m)IW =1.05

Massive sheet rock

Adopt distribution of stress as 2V to 1H rule. Neglect the secondary consolidation settlement

Apply g

6


below:







(-5.00m)IW =1.05

Massive sheet rock



Apply g

7

Determine the total settlement of the foundation, for the condition given below, Ground level /GWT(+)0.00m Sand with γsat =20.50 kN /cum

Apply g

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outcome

2 wide square transmitting a contact pressure of 320 kPa Foundation level (-2.00m) Fully saturated compressible clay γsat=21.00 kN/m

3 , L.L = 108%, e0=1.05, µ =0.28 , ES =19500 kPa

2 (-5.00m)IW =

1.05 Massive sheet rock Adopt distribution of stress as per 2V to 1H rule. Neglect the secondary consolidation settlement

8


below:






γsat =21.50 kN/m3

, L.L =98% , e0 = 1.00, µ = 0.24, Es =18500kN/m2

(-6.00m)IW =1.05

Massive sheet rock

Adopt distribution of stress as 2V to 1H rule. Neglect the secondary


Apply g

9


below:







(-5.00m)IW =1.05

Massive sheet rock


consolidation settlement.

Apply g

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outcome

10

A clay layer 24 m thick has a saturated unit weight of 18kN/m3. Ground water

level occurs at a depth of 4m. it is proposed to construct a RC foundation, length

48m and width 12m, on the top of the layer, transmitting a uniform pressure of

180kN/m2. Determine the settlement under its centre. E for clay is 33 MN/m

2

obtained from triaxial tests. Initial void ratio = 0.69. change in void ratio = 0.02

Apply g


1 A timber pile was driven by a drop hammer weighing 30 kN with a free fall of 1.2 m. The average penetration of the last few blows was 5 mm. What is the capacity of the pile according to Engineering News Formula?

Apply h

2 A pile is driven with a single acting steam hammer of weight 15 kN with a free fall of 900 mm. The final set, the average of the last three blows, is 27.5 mm. Find the safe load using the Engineering News Formula.

Apply h

3

A pile is driven in a uniform clay of large depth. The clay has an unconfined compression strength of 90 kN/m

2. The pile is 30 cm diameter and 6 m long.

Determine the safe frictional resistance of the pile, assuming a factor of safety

of 3. Assume the adhesion factor = 0.7.

Apply h

4

A group of 16 piles of 50 cm diameter is arranged with a centre to centre spacing of 1.0 m. The piles are 9 m long and are embedded in soft clay with cohesion 30 kN/m

2.Bearing resistance may be neglected for the piles—Adhesion

factor is 0.6. Determine the ultimate load capacity of the pile group.

Apply h

5

A square group of 9 piles was driven into soft clay extending to a large depth. The diameter and length of the piles were 30 cm and 9 m respectively. If the unconfined compression strength of the clay is 90 kN/m

2, and the pile spacing is

90 cm centre to centre, what is the capacity of the group? Assume a factor of safety of 2.5 and adhesion factor of 0.75.

Apply h

6 Design a square pile group to carry 400 kN in clay with an unconfined compression strength of 60 kN/m

2. The piles are 30 cm diameter and 6 m long.

Adhesion factor may be taken as 0.6. Apply

h

7 A 30 cm diameter pile penetrates a deposit of soft clay 9 m deep and rests on sand. Compute the skin friction resistance. The clay has a unit cohesion of 0.6 kg/cm

2. Assume an adhesion factor of 0.6 for the clay.

Apply h

8 A square pile 25 cm size penetrates a soft clay with unit cohesion of 75 kN/m

2

for a depth of 18 m and rests on stiff soil. Determine the capacity of the pile by skin friction. Assume an adhesion factor of 0.75.

Apply h

9

A square pile group of 9 piles of 25 cm diameter is arranged with a pile spacing of 1 m. The length of the piles is 9 m. Unit cohesion of the clay is 75 kN/m

2.

Neglecting bearing at the tip of the piles determine the group capacity. Assume adhesion factor of 0.75.

Apply h

10

Determine the group efficiency of a rectangular group of piles with 4 rows, 3 piles per row, the uniform pile spacing being 3 times the pile diameter. If the individual pile capacity is 100 kN, what is the group capacity according to this concept?

Apply h


1 A Cylindrical Well is of 6 m external diameter and 3.6 m internal diameter, and is to be sunk to a depth of 15 m below the scour level. It is subjected to a

Apply h

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horizontal load of 600 kN at a height of 9 m above the scour level. Determine the allowable resisting force due to earth pressure, using Terzaghi’s approach assuming that (a) the well rotates about a point above base, and (b) the well rotates about the base. γ’ = 9.9 kN/m

3; φ = 30°, and factor of safety against

passive resistance = 2.5.

2

A cylindrical well of external diameter 6 m and internal diameter 4 m is sunk to a depth 16 m below the maximum scour level in a sand deposit. The well is subjected to a horizontal force of 1000 kN acting at a height of 8 m above the scour level. Determine the total allowable equivalent resisting force due to earth pressure, assuming that (a) the well rotates about a point above the base, and (b) the well rotates about the base. Assume γ’=10kN/m

3, φ = 30°, and factor

of safety against passive resistance = 2. Use Terzaghi’s approach.

Apply h

3

A circular well of 6m external diameter and 4m internal diameter is embedded to a depth of 15m below the maximum scour level in a sandy soil deposit. The well is subjected to a horizontal force of 800kN acting at a height of 8m above the scour level. Determine the allowable total equivalent resisting force due to the earth pressure assuming the rotation is about a point above the base. Take γsat = 30kN/m

3, φ = 20°, factor of safety for passive resistance = 2. Use Terzaghi’s

analysis.

Apply h

4

A circular well of 6m external diameter and 4m internal diameter is embedded to a depth of 15m below the maximum scour level in a sandy soil deposit. The well is subjected to a horizontal force of 800kN acting at a height of 8m above the scour level. Determine the allowable total equivalent resisting force due to the earth pressure assuming the rotation is at the base. Take γsat = 20kN/m

3, φ =

30°, factor of safety for passive resistance = 2. Use Terzaghi’s analysis.

Apply h

5

A Cylindrical Well is of 6 m external diameter and 3.6 m internal diameter, and is to be sunk to a depth of 15 m below the scour level. It is subjected to a horizontal load of 700 kN at a height of 9 m above the scour level. Determine the allowable resisting force due to earth pressure, using Terzaghi’s approach assuming that (a) the well rotates about a point above base, and (b) the well rotates about the base. γ’= 15kN/m

3; φ= 30°, and factor of safety against

passive resistance = 2.5.

Apply h

6

A circular well of 6m external diameter and 4m internal diameter is embedded to a depth of 15m below the maximum scour level in a sandy soil deposit. The well is subjected to a horizontal force of 600kN acting at a height of 8m above the scour level. Determine the allowable total equivalent resisting force due to the earth pressure assuming the rotation is about a point above the base. Take γsat = 30kN/m

3, φ = 15°, factor of safety for passive resistance = 2. Use Terzaghi’s

analysis.

Apply h

7

A cylindrical well of external diameter 6 m and internal diameter 4 m is sunk to a depth 16 m below the maximum scour level in a sand deposit. The well is subjected to a horizontal force of 1000 kN acting at a height of 8 m above the scour level. Determine the total allowable equivalent resisting force due to earth pressure, assuming that (a) the well rotates about a point above the base, and (b) the well rotates about the base. Assume γ’= 15kN/m

3, φ = 20°, and

factor of safety against passive resistance = 2. Use Terzaghi’s approach.

Apply h

8

A circular well of 6m external diameter and 4m internal diameter is embedded to a depth of 15m below the maximum scour level in a sandy soil deposit. The well is subjected to a horizontal force of 900kN acting at a height of 8m above the scour level. Determine the allowable total equivalent resisting force due to the earth pressure assuming the rotation is at the base. Take γsat = 30kN/m

3, φ =

Apply h

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30°, factor of safety for passive resistance = 2. Use Terzaghi’s analysis.

Prepared By: Ms. Y. Shireesha

INSTITUTE OF AERONAUTICAL ENGINEERING - · PDF file · 2015-04-17... P a g e...

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Transcript of INSTITUTE OF AERONAUTICAL ENGINEERING - · PDF file · 2015-04-17... P a g e...