course file on foundation engineering by ch.hari...

Course File On

FOUNDATION ENGINEERING

By

CH.HARI PRASAD

Assistant Professor,

Civil Engineering

K. G. Reddy College Of Engineering and Technology

2019-2020

KG Reddy College of Engineering & Technology

(Approved by AICTE, New Delhi, Affiliated to JNTUH, Hyderabad)

Chilkur (Village), Moinabad (Mandal), R. R Dist, TS-501504

CH.HARI PRASAD , Assistant Professor

COURSE FILE Subject (Name) : FOUNDATION ENGINEERING

Name (of the Faculty Member) : CH.HARI PRASAD

Designation : Assistant Professor

Regulation /Course Code : R 16 / CE723PE

Year / Semester : IV / I

Department : Civil Engineering

Academic Year : 2019-20





COURSE FILE CONTENTS

S.N. Topics Page No.

1 COURSE OBJECTIVES AND COURSE

OUTCOMES

2 COURSE PREREQUISITES

3 SYLLABUS (UNIVERSITY COPY)

4 COURSE INFORMATION SHEET (CIS)

a). Course Description

b). Syllabus

c). Gaps in Syllabus

d). Topics beyond syllabus

e). Web Sources-References

f). Delivery / Instructional Methodologies

g). Assessment Methodologies-Direct

h). Assessment Methodologies –Indirect

i). Text books & Reference books

5 Vision, Mission, PEO’s, & PO’s

6 Micro Lesson Plan

7 Teaching Schedule

8 Course Objectives, TO’s, CO’s, PO’s, & PEO’s

Mapping

9 Lecture Plan and Notes -Unit Wise

10 OHD/LCD SHEETS /CDS/DVDS/PPT (SOFT/HARD

COPIES)





11 University Previous Question papers

12 MID exam Descriptive Question Papers

13 MID exam Objective Question papers

14 Assignment topics with materials

15 Tutorial topics and Questions

16 Unit wise-Question bank

1 Two marks question with answers 5

questions

2 Three marks question with answers 5

questions

3 Five marks question with answers 5

questions

4 Objective question with answers 10

questions

5 Fill in the blanks question with

answers

10

questions

17 Beyond syllabus Topics with material

18 Sample Students Descriptive Answer sheets

19 Sample Students Assignment Sheets

21 Record of Tutorial Classes

22 Record of Remedial Classes

23 Record of guest lecturers conducted





1. VISION, MISSION, PROGRAM EDUCATIONAL OBJECTIVES (PEOs),

PROGRAM OUTCOMES (POs) & PROGRAM SPECIFIC OUTCOMES

(PSOs)

Vision

To give the world new age civil engineers who can transform the society with their creative vibe for

the sustainable development by instilling scientific temper with ethical human outlook.

Mission

To make the department a centre of excellence in the field of civil engineering and allied

research.

To promote innovative and original thinking in the minds of budding engineers to face the

challenges of future.





Program Educational Objectives (PEOs)

PEO 1

Graduates will utilize the foundation in Engineering and Science to

improve lives and livelihoods through a successful career in civil

Engineering or other fields.

PEO 2

Graduates will become effective collaborators and innovators, leading or

participating in efforts to address Social, Technical and Business

challenges.

PEO 3

Graduates will engage in Life-Long Learning and professional

development through Self-Study, continuing education or graduate and

professional studies in engineering & Business.

Program Outcomes (POs)

PO1 Fundamental engineering analysis skills: An ability to apply

knowledge of computing, mathematical foundations, algorithmic

principles, and civil engineering theory in the modelling and design

of to civil engineering problems.

PO2 Information retrieval skills: An ability to design and conduct

experiments, as well as to analyze and interpret data.

PO3 Creative skills: An ability to design, implement, and evaluate a

system, process, component, or program to meet desired needs,

within realistic constraints such as economic, environmental, social,

political, health and safety, manufacturability, and sustainability.

Graduates have design the competence.

PO4 Teamwork: An ability to function effectively on multi-disciplinary

teams.

PO5 Engineering problem solving skills: An ability to analyze a

problem, and identify, formulate and use the appropriate computing





and engineering requirements for obtaining its solution.

PO6 Professional integrity: An understanding of professional, ethical,

legal, security and social issues and responsibilities. Graduates

must understand the principles of ethical decision making and can

interpret the ASCE Code of Ethics. Graduates will understand the

proper use of the work of others (e.g., plagiarism, copyrights, and

patents). Graduates will understand the special duty they owe to

protect the public's health, safety and welfare by virtue of their

professional status as engineers in society.

PO7 Speaking / writing skills: An ability to communicate effectively,

both in writing and orally. Graduates are able to produce

engineering reports using written, oral and graphic methods of

communication.

PO8 Engineering impact assessment skills: The broad education

necessary to analyze the local and global impact of computing and

engineering solutions on individuals, organizations, and society.

PO9 Social awareness: Knowledge of contemporary issues. Students

are aware of emerging technologies and current professional issues.

PO10 Practical engineering analysis skills: An ability to use the

techniques, skills, and modern engineering tools necessary for

engineering practice.

PO11 Software hardware interface: An ability to apply design and

development principles in the construction of software and

hardware systems of varying complexity.

PO12 Successful career and immediate employment: An ability to

recognize the importance of professional development by pursuing

postgraduate studies or face competitive examinations that offer

challenging and rewarding careers in Civil Engineering





Program Specific Outcomes (PSOS)

PSO DESCRIPTION

PSO 1 Educating students with fundamental mathematical, scientific, and engineering

knowledge to have a significant and positive long-term impact on the field of civil

engineering.

PSO 2 Emphasizing the importance of working in a team effect ively and to

communicate properly within the team to achieve the desired outcome.

PSO 3 Motivate students in learning to learn and the ability to keep learning for a lifetime

to increase their professionalism, update and deepen their knowledge through the

development of the profession.





2. SYLLABUS (UNIVERSITY COPY)





FOUNDATION ENGINEERING

(Professional Elective-II)

B.Tech. IV Year I Sem. L T/P/D C

Course Code: CE723PE 3 0/0/0 3

Pre-Requisites: Soil Mechanics

Course Objectives: To impart the knowledge on various soil exploration techniques,

and analyse and design of various substructures, such as slopes, retaining walls, shallow

foundations, and pile foundations.

Course Outcomes: At the end of the course, the student will be able to:

Check the stability of slopes, analyze, and design the shallow and pile foundations, and

earth retaining structures.

UNIT – I

Soil Exploration: Need – methods of soil exploration – boring and sampling methods –

penetration tests – plate load test – pressure meter – planning of soil exploration

programme and preparation of soil investigation report.

UNIT – II

Slope Stability: Infinite and finite earth slopes – types of failures – factor of safety of

infinite slopes – stability analysis by Swedish slip circle method, method of slices,

Bishop’s Simplified method of slices – Taylor’s Stability Number- stability of slopes of

earth dams under different conditions.

UNIT – III

Earth Pressure Theories: At-rest earth pressures, Rankine’s theory of earth pressure

– earth pressures in layered soils – Coulomb’s earth pressure theory – Culmann’s graphical

method, effect of pore water, earth pressure due to surcharge loads.

Retaining Walls: Types of retaining walls – stability of gravity and cantilever retaining

walls against overturning, sliding and, bearing capacity modes of failure, Drainage from

backfill, introduction to reinforced earth walls.

UNIT – IV

Shallow Foundations - Types - choice of foundation – location and depth - safe

bearing capacity – shear criteria – Terzaghi’s, and IS code methods - settlement criteria –

allowable bearing pressure based on SPT N value and plate load test – allowable

settlements of structures.





UNIT - V

Pile Foundation: Types of piles – load carrying capacity of piles based on static pile

formulae – dynamic pile formulae – Pile Capacity through SPT and CPT results - pile load

tests - load carrying capacity of pile groups in sands and clays – Settlement of pile groups

– negative skin friction

Well Foundations: Types – different shapes of wells – forces on wells - components of

wells -Grip length – sinking of wells – tilts and shifts.

TEXT BOOKS:

1. Das, B.M., - (2011) Principles of Foundation Engineering –7th edition, Cengage

Publishing.

2. Foundation Design Principles and Practices, Donald P. Coduto, 2nd Edition,

Pearson Publishers.

3. Bowles, J.E., (2012) Foundation Analysis, and Design – 5th Edition, McGraw-Hill

Publishing company, Newyork.

REFERENCES: 1. Geotechnical Engineering by S. K. Gulhati & Manoj Datta – Tata Mc Graw Hill

Publishers New Delhi. 2005.

2. Soil Mechanics and Foundation Engineering by VNS Murthy, CBS Publishers, and

Distributors.

3. Basic and Applied Soil Mechanics by Gopal Ranjan & ASR Rao, New age

International Pvt. Ltd, New Delhi

4. Analysis and Design of Substructures – Swami Saran, Oxford, and IBH Publishing

company Pvt Ltd (1998).

5. Soil Mechanics and Foundation Engineering by B. N. D. Narasinga Rao,

Wiley (2015).

6. Geotechnical Engineering by Debsashis Mitra Universities Press (2016).





3. COURSE OBJECTIVES, COURSE OUTCOMES AND TOPIC OUTCOMES

COURSE OBJECTIVES

The course should enable the students to:

1. To enable to use simple mathematics to derive relationships among soil properties

2. Analyze the elementary partial differential equations to solve simple boundary-value flow and consolidation problems.

3. Basics of Soil Mechanics, Statics, and Strength of Materials are utilized in this course for foundation.

4. Design of shallow and deep foundations, retaining walls, geo-synthetic-reinforced soil structures, and design of slopes will be dealt.

5. Design of well foundation and components of well foundation

6. Design of shallow foundation by different methods

COURSE OUTCOMES

At the end of the course, the students will be able to:

CO1. Analyze the need and methods of soil exploration

CO2. Ability to relate the field test and soil investigation

CO3. Apply knowledge and design stability of slopes for earth dams under different conditions

CO4. Analyzing earth pressure theories and design of retaining walls

CO5. Analyzing the theory of shallow foundations and well foundations

CO6. Analyzing the theory of well foundations.





TOPIC OUTCOMES

Lecture

no.

Topic to be covered Topic outcome

(at the end of this course, the student

will be able to)

Unit-I

1 Introduction to Soil Exploration and

needs

To identify the different types of

soils underground and its strength

2 Methods of soil Exploration To analyse the different soils with

different types of methods

3 Boring and Sampling methods To identify the soils by boring

methods and sampling methods

4 Penetration tests To analyse the under the ground

surface by using penetration test

5 Plate load test To analyse the underground soil and

by using plate load test to find out

the strength of the soil

6 Pressure meter Illustrate soil parameters using

Pressure meter test

7 planning of Programme of soil

exploration

Demonstrate the methods for finding

different types of soils and their

parameters

8 preparation of soil investigation report To characterise the soil with

different types of methods.

Unit-II

9 Introduction of Infinite and finite earth

slopes

Overview of slope stability

10 types of failures Define failures and classify the

types.

11 factor of safety of infinite slopes To define factor of safety for

cohesion and cohesion less soil for

infinite slopes

12 stability analysis To analyse the stability for different

types of slopes

13 Swedish arc method Derive the slices to identify the gaps

between the slope failures

14 standard method of slices Derive the Swedish arc methods to

identifying the factor of safety

15 Bishop‘s Simplified method Derive the slices to identify the gaps

between the slope failures





16 Taylor‘s Stability Number Derive the Bishop‘s Simplified

method methods to identifying the

factor of safety

17 Stability of slopes of earth dams under

different conditions.

Derive the Taylor‘s Stability Number

method to identifying the factor of

safety


different conditions

To identify the Stability of slopes of

earth dams under different

conditions.

19 Problems Calculate the factor of safety in

Swedish arc method, Bishop‘s

Simplified method, Taylor‘s

Stability Number.

20 Problems

UNIT-III

21 Interdiction of Earth pressure theories Overview of lateral earth pressure

and retaining walls

22 Rankine‘s theory of earth pressure To derive the Rankine‘s theory of

earth pressure

23 earth pressures in layered soils To identify the earth pressures in

layered soils

24 Coulomb‘s earth pressure theory To derive the Coulomb‘s earth

pressure theory

25 Coulomb‘s earth pressure theory Illustrate the Culmann‘s graphical

method

26 Coulomb‘s earth pressure theory Overview of retaining walls.

27 Culmann‘s graphical method. To classify the types of retaining

walls

28 Interdiction of retaining walls To analyse the stability of retaining

walls against overturning, sliding,

bearing capacity design

29 Types of retaining walls To identify the drainage from

backfill

30 stability of retaining walls against

overturning, sliding, bearing capacity

design

Calculate the conditions of K0,Kp,Ka

and cohesive soil conditions.













33 drainage from backfill Calculate the conditions of K0,Kp,Ka


34 Problems

UNIT-IV

35 Interdiction of shallow foundations Overview of foundations

36 Types of foundations Classify the Types of foundations

37 choice of foundation, Location of depth To analyse the Safe Bearing

Capacity

38 Interdiction of Safe Bearing Capacity To determine Safe Bearing Capacity

by Terzaghi

39 Safe Bearing Capacity by Terzaghi, To determine Safe Bearing Capacity

by Meyerhof

40 Safe Bearing Capacity by Meyerhof, To determine Safe Bearing Capacity

by Skempton

41 Safe Bearing Capacity by Skempton To determine Safe bearing pressure

based on N- value- allowable

bearing pressure

42 Safe bearing pressure based on N- value-

allowable bearing pressure

To determine Safe bearing pressure

based on N- value- allowable

bearing pressure

43 safe bearing capacity To derive the safe bearing capacity

44 plate load test To analyse the underground soil and

by using plate load test to find out

the strength of the soil

45 allowable settlements of structures To analyse the allowable settlements

of structures

46 Types of piles Classify the Types of piles

47 Load carrying capacity of piles based on

static pile formulae in Dynamic pile

formulae

To derive the Load carrying capacity

of piles based on static pile formulae

in Dynamic pile formulae

48 Pile load tests To analyse the underground soil and

by using pile load test to find out the

strength of the soil in different piles.





49 Load carrying capacity of pile groups in

sands and clays

To identify the Load carrying

capacity of pile groups in sands and

clays

50 Settlement of pile groups To analyse the Settlement of pile

groups

51 Problems Calculate the settlement of pile

groups and Load carrying capacity

of pile groups.

UNIT-V

52 Interdiction of well foundation and types Overview of well foundations

53 Different shapes of wells Classify the Different shapes of

wells

54 Components of wells Classify the Different shapes of

wells

55 Sinking of well- To identify the Components of wells

56 Tilts and shifts To identify the Components of wells

57 Problems To identify the Sinking of well.

Calculate the problems on Sinking

of wells.





4. COURSE PRE–REQUISITES

a) Engineering Geology

b) Structural analysis

c) Geo technical engineering





5. CO’s, PO’s MAPPING

PO

1

PO2 PO

3

PO

4

PO

5

PO

6

PO

7

PO

8

PO

9

PO1

0

PO1

1

PO1

2

CO

1

M - H - - - - - - - - -

CO

2

- M H - - - - - - - - -

CO

3

- M H - - - - - - - - -

CO

4

- M H - - - - - - - - -

CO

5

- M H - - - - - - - - -

NOTES: L – Low, M – Medium, H - High





6. COURSE INFORMATION SHEET

a) COURSE DESCRIPTION:

PROGRAMME: B. Tech. (Civil Engineering.) DEGREE: BTECH

COURSE: Foundation engineering YEAR: IV SEM: I

CREDITS: 4

COURSE CODE:CE: CE723PE

REGULATION: R16

COURSE TYPE: CORE

COURSE AREA/DOMAIN: Design CONTACT HOURS: 4+0 (L+T)

hours/Week.

CORRESPONDING LAB COURSE CODE (IF

ANY):NO

LAB COURSE NAME:NO

b) SYLLABUS:

Unit Details Hours

I

Soil exploration: Need Methods of soil exploration-Boring and Sampling

Methods-Penetration Test-Plate load Test-Pressure Meter Test-Planning

program and preparation of soil investigation report 10

II

Infinite and finite earth slopes- types of failures- factor of safety of

infinite slopes- stability analysis by

Swedish arc method, standard method of slices, Bishop‘s Simplified method- Taylor‘s Stability Number-Stability of slopes of earth dams under different conditions.

14

III

EARTH PRESSURE THEORIES: Rankine‘s theory of earth pressure- earth pressures in layered soils-Coulomb‘s earth pressure theory- Culmann‘s graphical method.

RETAINING WALLS: Types of retaining walls- stability of retaining

walls against overturning, sliding, bearing capacity and drainage from

backfill.

17

IV

SHALLOW FOUNDATIONS-Strength Criteria: Types, choice of foundation, Location of depth-, Safe Bearing Capacity, Terzaghi, Meyerhof, Skempton and IS Methods.

SHALLOW FOUNDATIONS-Settlement criteria: Safe bearing pressure based on N- value- allowable bearing pressure, safe bearing

19





capacity, plate load test, allowable settlements of structures.

PILE FOUNDATION: Types of piles- Load carrying capacity of

piles based on static pile formulae in Dynamic pile formulae, Pile load

tests, Load carrying capacity of pile groups in sands and clays,

Settlement of pile groups.

V WELL FOUNDATIONS: Types- Different shapes of wells- Components of wells- Sinking of well- Tilts and shifts. 9

Total No. of classes 68

c) GAPS IN THE SYLLABUS - TO MEET INDUSTRY/PROFESSION REQUIREMENTS:

NIL

d) TOPICS BEYOND SYLLABUS/ ADVANCED TOPICS: NIL

e) WEB SOURCE REFERENCES:

f) DELIVERY/INSTRUCTIONAL METHODOLOGIES:

CHALK & TALK STUD. ASSIGNMENT WEB RESOURCES

LCD/SMART BOARDS STUD. SEMINARS ☐ ADD-ON COURSES

g) ASSESSMENT METHODOLOGIES-DIRECT

ASSIGNMENTS STUD. SEMINARS TESTS/MODEL

EXAMS

UNIV.

EXAMINATION

☐ STUD. LAB

PRACTICES

☐ STUD. VIVA ☐ MINI/MAJOR

PROJECTS

☐ CERTIFICATIONS

☐ ADD-ON

COURSES

☐ OTHERS

Sl. No. Name of book/ website

a. https://www.youtube.com/watch?v=0z6gjjrSn0M

b. https://www.youtube.com/watch?v=91fCagGP5Is

c. https://www.youtube.com/watch?v=PDBfY4FM9qY

d. https://www.youtube.com/watch?v=v0753-IzyB8

https://www.youtube.com/watch?v=0z6gjjrSn0M

https://www.youtube.com/watch?v=91fCagGP5Is

https://www.youtube.com/watch?v=PDBfY4FM9qY

https://www.youtube.com/watch?v=v0753-IzyB8





h) ASSESSMENT METHODOLOGIES-INDIRECT

ASSESSMENT OF COURSE OUTCOMES

(BY FEEDBACK, ONCE)

STUDENT FEEDBACK ON

FACULTY (TWICE)

☐ASSESSMENT OF MINI/MAJOR PROJECTS

BY EXT. EXPERTS

☐ OTHERS

i) TEXT/REFERENCE BOOKS:

T/R BOOK TITLE/AUTHORS/PUBLICATION

Text Book 1. Murthy, V.N.S, ―Soil Mechanics and Foundation Engineering‖, UBS

Publishers Distribution Ltd, New Delhi, 1999.

Text Book 2. Gopal Ranjan and Rao, A.S.R. ‖Basic and Applied Soil Mechanics‖,

Wiley Eastern Ltd., New Delhi (India), 2003.

Reference

Book

1. Punmia, B.C., ―Soil Mechanics and Foundations‖, Laxmi publications

pvt. Ltd., New Delhi, 1995.

Reference

Book

3. Das, B.M. ―Principles of Foundation Engineering (Fifth edition),

Thomson Books / COLE, 2003

Reference

Book

4. Bowles J.E, ―Foundation analysis and design‖, McGraw-Hill, 1994

Reference

Book

5. Venkatramaiah,C.‖Geotechnical Engineering‖, New Age International

Publishers, New Delhi, 1995





7. MICRO LESSON PLAN

S.No. Topic Scheduled date Actual date

Unit-I

1 Introduction to Soil Exploration and needs

2 Methods of soil Exploration

3 Boring and Sampling methods

4 Penetration tests

5 Plate load test

6 Pressure meter

7 planning of Programme of soil exploration

8 preparation of soil investigation report

9 Revision

10 ppt

Unit-II

11 Introduction of Infinite and finite earth

slopes

12 types of failures

13 factor of safety of infinite slopes

14 stability analysis

15 Swedish arc method

16 standard method of slices

17 Bishop‘s Simplified method

18 Taylor‘s Stability Number






different conditions.


different conditions

21 Problems

22 Problems

23 Revision

24 Ppt

UNIT-III

25 Interdiction of Earth pressure theories

26 Rankine‘s theory of earth pressure

27 earth pressures in layered soils

28 Coulomb‘s earth pressure theory



31 Culmann‘s graphical method.

32 Interdiction of retaining walls

33 Types of retaining walls


overturning, sliding, bearing capacity design





37 drainage from backfill





38 Problems

39 Revision

40 Ppt

UNIT-IV

41 Interdiction of shallow foundations

42 Types of foundations

43 choice of foundation, Location of depth

44 Interdiction of Safe Bearing Capacity

45 Safe Bearing Capacity by Terzaghi,

46 Safe Bearing Capacity by Meyerhof,

47 Safe Bearing Capacity by Skempton

48 Safe bearing pressure based on N- value-

allowable bearing pressure

49 safe bearing capacity

50 plate load test

51 allowable settlements of structures

52 Types of piles

53 Load carrying capacity of piles based on

static pile formulae in Dynamic pile

formulae

54 Pile load tests

55 Load carrying capacity of pile groups in

sands and clays

56 Settlement of pile groups





57 Problems

58 Revision

59 Ppt

UNIT-V

60 Interdiction of well foundation and types

61 Different shapes of wells

62 Components of wells

63 Sinking of well-

64 Tilts and shifts

65 Problems

66 Problems

67 Revision

68 Ppt





8. TEACHING SCHEDULE

Subject Foundation Engineering

Text Books (to be purchased by the Students)

Book 1 1. Murthy, V.N.S, ―Soil Mechanics and Foundation Engineering‖, UBS Publishers Distribution Ltd, New Delhi, 1999.

Book 2 2. Gopal Ranjan and Rao, A.S.R. ‖Basic and Applied Soil Mechanics‖, Wiley

Eastern Ltd., New Delhi (India), 2003 Reference Books

Book 3 3. Das, B.M. ―Principles of Foundation Engineering (seventh edition), Thomson

Books / COLE, 2003

Book 4 4. Bowles J.E, ―Foundation analysis and design‖, McGraw-Hill, 1994

Book 5 5. Punmia, B.C., ―Soil Mechanics and Foundations‖, Laxmi publications pvt. Lt.

d., New Delhi, 1995

Book 6 6. Venkatramaiah,C.‖Geotechnical Engineering‖, New Age International Publishers,

New Delhi, 1995

Unit

Topic Chapters Nos No of classes

Book 1 Book 2 Book 3 B

o

o

k

4

I

Introduction to Soil Exploration

and needs

9 19 18 1

Methods of soil Exploration 9 19 18 1

Boring and Sampling methods 9 19 18 1

Penetration tests 9 19 18 1

Plate load test 15 15 16 1

Pressure meter test 9 19 18 1

planning of Programme of soil

exploration 9 19 18 1





preparation of soil investigation

report 9 19 18 1

II

Introduction of Infinite and

finite earth slopes 10 11 15 1

types of failures 10 11 15 1

factor of safety of infinite slopes 10 11 15 1

stability analysis 10 11 15 1

Swedish arc method 10 11 15

1

Bishop‘s Simplified method 10 11 15 1

Taylor‘s Stability Number 10 11 15 1

Stability of slopes of earth dams

under different conditions. 10 11 15 1

Stability of slopes of earth dams

under different conditions 10 11 15 1

Problems 10 11 15 1

Problems 10 11 15 1

III

Interdiction of Earth pressure

theories 11 12 13 1

Rankine‘s theory of earth

pressure 11 12 13 1

earth pressures in layered soils 11 12 13 1

Coulomb‘s earth pressure theory 11 12 13 1



Culmann‘s graphical method. 11 12 13 1

Interdiction of retaining walls 11 12 13 1





stability of retaining walls against

overturning, sliding, bearing

capacity design

11 12 13 1



capacity

11 12 13 1



capacity

11 12 13 1

drainage from backfill 11 12 13 1

Problems 11 12 13 1

IV

Interdiction of shallow

foundations 12 15 13 1

Types of foundations 12 15 16 1

choice of foundation, Location of

depth 12 15 16 1

Interdiction of Safe Bearing

Capacity 12 15 16 1

Safe Bearing Capacity by

Terzaghi 12 15 16 1


Meyerhof 12 15 16 1


Skempton 12 15 16 1

Safe bearing pressure based on

N- value- allowable bearing

pressure

13 15 16 1

safe bearing capacity 13 15 16 1

plate load test 13 16 16 1

allowable settlements of

structures 13 16 16 1

Types of piles 16 16 1

Load carrying capacity of piles

based on static pile formulae in

Dynamic pile formulae

14 16 16 1





Pile load tests 14 16 16 1

Load carrying capacity of pile

groups in sands and clays 14 16 16 1

Settlement of pile groups 14 16 16 1

Problems 14 16 16 1

V

Interdiction of well foundation

and types 20 17 - 1

Different shapes of wells 20 17 - 1

Components of wells 20 17 - 1

Sinking of well 20 17 - 1

Tilts and shifts 20 17 - 1

Problems 20 17 - 1

Contact classes for syllabus coverage 68





9. UNIT WISE HAND WRITTEN NOTES





10. UNIT WISE PPT





11. PREVIOUS QUESITION PAPERS





12) MID EXAM DESCRIPTIVE QUESTION PAPER WITH KEY

K. G. Reddy College of Engineering &Technology

(Approved by AICTE, Affiliated to JNTUH)

Chilkur (Vil), Moinabad (Mdl), RR District

MID 1

Q.N

O QUESTION

Bloom’s

level

Course

outcome

1

A) What soil exploration? What are the needs

of soil exploration?

B) Define soil samplers? Explain any two

types of soil samplers

UNDERST

SNDING CO1

2

A) Explain short notes on standard penetration test

and their corrections.

B)Explain short notes on pressure meter test and neat

sketch.

UNDERST

ANDING CO1

3

A) Explain types of slope failures?

B) Explain the short notes on Swedish circle method

and neat sketch.

REMEMB

ERING CO2

4

A proposed cutting in a homogeneous cohesive soil

will have a slope angle of 250 and will be 8.0 m

deep. Using Taylors stability chart determine the

factor of safety against shear failure in respect of the

following soils.

i) Cu= 45 KN/m2 ; Qu =0; γ = 19 KN/ m2; D is large

ii) Cu= 45 KN/m2 ; Qu =0; γ = 19 KN/ m2; at a depth

of 12m

iii) Cu= 25 KN/m2 ; Qu =150; γ = 18.5 KN/ m2

ANALYZI

NG CO2





KEY

1. A) A geotechnical investigation will include surface and subsurface exploration of a site.

Sometimes, geophysical methods are used to obtain data about sites. Sub-surface exploration

usually involves soil sampling and laboratory tests of the soil samples retrieved.

1.To select the type and depth of foundation from the given structure of the load

2. To calculate the load-baring capacity of the foundation.

3. To calculate the differential settlement of the foundation.

4. To evaluate the foundation problems.

5. Locating the depth to the ground water table.

6. Computation of lateral earth pressure on the structure.

B) The structure of the soil is disturbed to the considerable degree by the action of the boring tools

or the excavation equipment’s.

The disturbances can be classified in following basic types:

Change in the stress condition

Change in the water content and the void ratio

Disturbance of the soil structure

Chemical changes,

Mixing and segregation of soil constituents

It retains as closely as practicable the true in situ structure and water content of the soil. For

undisturbed sample the stress changes cannot be avoided. The following requirements are looked

for:

No change due to disturbance of the soil structure,

No change in void ratio and water content,

No change in constituents and chemical properties.





2. Ans. Generally used for cohesion less soils

To determine relative density , angle of shearing resistance, UCC

A bore hole is made using drilling tools and a hammer of weight 63.5 falling from the height of 750

mm at the rate of 30 blows/minute

After reaching the specified depth, the drilling tool is replaced by a split spoon sampler to collect

soil sample.

First 150 mm penetration is taken as seating drive and the no. of blows required for thatPenetration

is discarded

No of blows required for next 300mm penetration after seating drive is taken as standard penetration

number (N)

No of blows greater than 50 are taken as refusal and the test is discontinued

Corrections are applied to the observed N value.

Correction to N value

Dilatancy Correction

Overburden correction

Of these, overburden correction is applied first and to that corrected value, dilatancy Correction is

applied.

Due to the presence of fine sand and silt below the water table, negative pore pressure develops

which increases, the observed N value. Hence correction is applied. (If N’<15 or

N=15, N’ = N)

Soils having the same relative density will show higher N value at greater depth due to presence





of over burden. Cohesion less soils are greatly affected by confining pressure. Hence N value is

corrected .σ <=280 kN/m2

3. Ans. The pressure meter test is an in-situ testing method used to achieve a quick

measure of the in-situ stress-strain relationship of the soil. In principle, the pressure meter

test is performed by applying pressure to the sidewalls of a borehole and observing the

corresponding deformation.

The pressure meter consists of two parts, the read-out unit which rests on the ground surface,

and the probe that is inserted into the borehole (ground). The original Ménard-type pressure

meter was designed to be lowered into a performed hole and to apply uniform pressure to the

borehole walls by means of inflatable flexible membrane. As the pressure increases, the

borehole walls deform. The pressure is held constant for a given period and the increase in

volume required for maintaining the constant pressure is recorded. A load-deformation

diagram and soil characteristics can be deduced by measurement of the applied pressure and

change in the volume of the expanding membrane.

The major difference between categories of pressure meter lies in the method f installation of

the instrument into the ground. Three main types of pressure meters are:

• The borehole pressure meter: The instrument is inserted into a performed hole.

• The self-boring pressure meter: The instrument is self-bored into the ground with the

purpose of minimizing the sol disturbance caused by insertion.

• Displacement pressure meters: The instrument is pushed into the ground from base of

a borehole. The soil displaced by the probe during insertion enters the body of instrument,

reducing the disturbance to the surrounding soil .

There are different approaches the interpretation of results and the determination of material

properties from pressure meter tests. In general, these approaches rely either on empirical

correlations to allow measured co-ordinates of pressure and displacement to be inserted

directly into design equations, or on solving the boundary problem posed by the pressure

meter test.







Chilkur (Vil), Moinabad (Mdl), RR District

Q.

NO

QUESTION Bloom’s level Course

outcome

1

A) Short notes on types of piles on the basis of method of

installation. Explain short notes on settlement of pile

groups?

B) explain the assumption of Terzaghi’s bearing capacity

and equation.

Understand CO3

2 A) Briefly short on types of wells? Explain different types

of shapes of wells?

B) With a neat sketch , state different components of well

foundation.

Understand CO3

3

A) Compute the ultimate bearing capacity of a rectangular

footing 2m x4m embaded 1.5m in a soil having C = 10 kpa,

γ = 18 kn/m3 , ø = 25° the load is eccentric and vertical .G

W T is at a depth of 1m below the ground surface. using

mayarhoffs method.

B) For a continuous foundation of 0.9 m depth and 1.2 m

width using terzaghis bearing capacity factors .determine

the safe load per unit area that the foundation can carry.

Given γ = 18 kn/m3 ,C = 10kn/m2,ø =200.factor of safety =

3.

Understand CO4

4

Check the stability of the gravity retaining wall shown in

fig. take the allowable pressure equal to 600 kn/m2 .use

coulombs theory .ø = 36, I = 0 ,δ=240.

Understand CO5





MID 2

KEY

2) a) Caissons are of three types.

i) Open caissons

ii) Box caissons

iii) Pneumatic caissons

These are the components.

i) Circular well

ii) Double D-well

iii) Dumb-bell

iv) Broad necked twin well with circular dredge holes

v) Double octagonal with circular dredge holes

vi) Multiple dredge hole well

B). . These are the components

i) Well cap

ii) Staining

iii) Curb

iv) Cutting edge

v) Bottom plug

vi) Dredge hole

vii) Top plug





13. MID EXAM OBJECTIVE QUESTION PAPER

MID- I





13. MID EXAM OBJECTIVE QUESTION PAPER

MID- II





14. ASSIGNMENT TOPICS WITH MATERIALS

UNIT 1

1. What do you understand by site investigation?

Ans. Before the engineer can design a foundation intelligently, he must have a reasonably

accurate conception of the physical properties and arrangement of the underlying materials.

The field and laboratory investigations required to obtain this essential information are called

soil exploration or site investigation. A site investigation simply is the process of the

collection of information, the appraisal of data, assessment, and reporting without which the

hazards in the ground beneath the site cannot be known.

2. What type of information is obtained in reconnaissance?

Ans. Civil reconnaissance is the process of gathering a broad spectrum of civil information

about a specific population in support of military operations. It is related to and often

performed in conjunction with infrastructure reconnaissance (assessment and survey).

Normally the focus of collection in the operational area for civil reconnaissance is collecting

civil information relating to the daily interaction between civilians and military forces. Civil

information encompasses relational, temporal, geospatial and behavioral information captured

in a socio-cultural backdrop. It is information developed from data related to civil areas,

structures, capabilities, organizations, people, and events, within the civil component of the

commander's operational environment that can be processed to increase situational awareness

and understanding.

3. Distinguish between disturbed and undisturbed samples?

Ans. Disturbed samples:

Disturbed samples are generally obtained to determine the soil type, gradation, classification,

consistency, density, presence of contaminants, stratification, etc. The methods for obtaining

disturbed samples vary from hand excavating of materials with picks and shovels to

usingtruck mounted augers and other rotary drilling techniques. These samples are considered

.disturbed. Since the sampling process modifies their natural structure.

Undisturbed samples: Undisturbed samples are used to determine the in place strength,

compressibility(settlement), natural moisture content, unit weight,

permeability, discontinuities, fractures and fissures of subsurface formations. Even though

such samples are designated as .undisturbed, in reality they are disturbed to varying degrees.

The degree of disturbance depends on the type of subsurface materials, type and condition of

the sampling equipment used, the skill of the drillers, and the storage and transportation

methods used.





4. How do you obtain undisturbed samples?

Ans. Undisturbed samples are those which are subjected to minimum disturbances. Purely

undisturbed sample is an ideal condition because all the samples will get disturbed to some

extent even though precise equipments are used. These samples are used in strength and

consolidation test

5. What is Boring log

Ans. Information on subsurface conditions obtained from the boring operation is typically

presented in the form of a boring record, commonly known as “boring log”. It consists of

1. Description or classification of various soil and rock type

2. Ground water table details

3.Test data in case of ‘lab log’





UNIT 2

1. Slope Failure Triggering Mechanisms

Ans. Intense Rain-Fall

• Water-Level Change

• Seepage Water Flow

• Volcanic Eruption

• Earthquake Shaking

• Human activity

2. Causes of Slope failure

Erosion: The wind and flowing water causes erosion of top surface of slope and makes the

slope steep and thereby increase the tangential component of driving force.

Steady Seepage: Seepage forces in the sloping direction add to gravity forces and make the

slope susceptible to instability. The pore water pressure decrease the shear strength. This

condition is critical for the downstream slope.

Sudden Drawdown: in this case there is reversal in the direction flow and results in

instability of side slope. Due to sudden drawdown the shear stresses are more due to

saturated unit weight while the shearing resistance decreases due to pore water pressure that

does not dissipate quickly.

Rainfall: Long periods of rainfall saturate, soften, and erode soils. Water enters into

existing cracks and may weaken underlying soil layers, leading to failure, for example, mud

slides.

3. Types of failure

Broadly slope failures are classified into 3 types as

1. Face (Slope) failure

2. Toe failure

3. Base failure





4. Finite Slopes: Analysis

A finite slope is one with a base and top surface, the height being limited.

• The inclined faces of earth dams, embankments, excavation and the like are all finite

slopes.

• Investigation of the stability of finite slopes involves the following steps –

a) assuming a possible slip surface,

b) studying the equilibrium of the forces acting on this surface, and –

c) Repeating the process until the worst slip surface, that is, the one with

d) minimum margin of safety is found.

5. Analysis cases

Case (i) Cohesionless soil

Case (ii) Cohesive soil

• Case (iii) Cohesive-frictional soil.





UNIT 3

1. A retaining wall with a smooth vertical back retains dry sand backfill for a depth of 3 m. The

backfill has a level surface and has the following properties. c = 0: $=30";y = 16k~/m. Calculate

the magnitude of the total active earth thrust against the wall assumng the wall is free to move

and its point of application.

2.





3.





UNIT 4

1. Types of shallow foundations

1. Spread footings

2. Combined footings

3. Strap or cantilever footings

4. Mat or raft foundation

2. Combined footings

Are preferred when 2 individual column other.

o It is economical.

o Provided when bearing capacity of soil is area under individual footing. are close to

each less,requiring more

o Combined footing may be rectangular,Trapezoidal or column-wall.

o If the columns carry equal loads, the footing is of rectangular shape, otherwise its

trapezoidal shape.

3. Pile Foundations

BS8004 defines deep foundation with D>B or D>3m.

Pile foundation always more expensive than shallow foundation but will overcome

problems of soft surface soils by transferring load to stronger, deeper stratum, thereby

reducing settlements.

Pile resistance is comprised of

end bearing

shaft friction

For many piles only one of these components is important. This is the basis of a

simple classification

4. Types of Pile

The pile installation procedure varies considerably,and has an important influence on the

subsequent response

o Three categories of piles are classified by method of installation as below:

o Large displacement piles

o They encompass all solid driven piles including precast concrete piles, steel or

concrete tubes closed at the lower end

o Small displacement piles





o They include rolled steel sections such as H-pile and open-end tubular piles

o Replacement piles

o They are formed by machine boring, grabbing or hand-digging

5. Modes of failure

o The soil is always failure by punching shear.

o The failure mode of pile is always in buckling failure mode.





UNIT 5

1. What is aWell Foundation?

Large hollow open-ended structure which is generally built in parts and sunk through

ground or water to its final position,where it forms part of the permanent foundation.

2. Uses of Well or Caisson Foundation

Usually very suitable in deep sandy or soft soils.

Specially for Boulder Stratum.

Used to - Support andTransfer Heavy Loads (Vertical and Horizontal) and Moments

Resist Uplift Forces

Reduce Differential Settlement

Support Heavy Structuresincluding

3. TYPES OF WELLS OR CAISSONS

Depending on the Method of Installation- 3Types

(a) Open Caisson orWell

(b) Box Caisson or Floating Caisson

(c) Pneumatic Caisson

4. SHAPES OF WELLS

1. CircularWell

2. Double D-Well

3. Dumb-BellWell

4. Broad NeckedTwinWell with Circular Dredge Holes

5. Double Octagonal with Circular Dredge HoleWell

6. Multiple Dredge HoleWell

7. Double OctagonalWell





8. Double RectangularWell

5. FORCES ACTING ON WELL FOUNDATION

Self-weight of well

o Buoyancy

o Dead load of super structure,substructure

o Live load

o Kentledge during sinking operation

o Impact load due to live load only in the design of pier cap and bridge seat on the

abutment

.





15. TUTORIAL TOPICS AND QUESTIONS

(NIL)





16. UNIT WISE QUESTION BANK

UNIT 1

2 MARK QUESTIONS WITH ANSWERS:

1. What type of information is obtained in reconnaissance?

Ans. It is the first step in a sub-surface exploration. It includes a visit to the site and to study the

maps and other relevant records. It helps in deciding feature programme of site investigations,

scope of work, methods of exploration to be adopted, types of samples to be taken and

laboratory testing and in-situ testing.

2. How do you obtain undisturbed samples?

Ans. Undisturbed soil samples retain the structural integrity of the in-situ soil and have a high

recovery rate within the sampler. Collecting a perfectly undisturbed sample is difficult and the

samplers may contain a small portion of undisturbed soil at the top and bottom of the sample

length

3. What do you understand by site investigation

Ans. Site investigation is carried out in order to determine the engineering properties of soil and

rock and how they will interact with a planned development. The purpose of site investigation

is to establish parameters of foundation, substructure and infrastructure design and to assess the

potential geotechnical, geo-environmental, geological and hydrological risk to humans,

property and the environment.

4. Explain various methods of drilling holes

Ans. Auger Drilling. ...

Rotary Air Percussion drilling (Air Percussion) ...

Core drilling

Cable tool drilling

Reverse circulation (RC) drilling

Diamond core drilling

Diamond core drill bits

Direct Push Drilling





5. Define soil exploration. Discuss the need of soil exploration

Ans. A geotechnical investigation will include surface and subsurface exploration of a site.

Sometimes, geophysical methods are used to obtain data about sites. Sub-surface exploration

usually involves soil sampling and laboratory tests of the soil samples retrieved.

1.To select the type and depth of foundation from the given structure of the load

2. To calculate the load-baring capacity of the foundation.

3. To calculate the differential settlement of the foundation.

4. To evaluate the foundation problems.

5. Locating the depth to the ground water table.

6. Computation of lateral earth pressure on the structure.





3 MARK QUESTIONS WITH ANSWERS:

1.what is Displacement boring?

Ans- Displacement borings

It is combined method of sampling & boring operation. Closed bottom sampler, slit cup, or

piston type is forced in to the ground up to the desired depth. Then the sampler is detached from

soil below it, by rotating the piston, & finally the piston is released or withdrawn. The sampler is

then again forced further down & sample is taken. After withdrawal of sampler & removal of

sample from sampler, the sampler is kept in closed condition & again used for another depth.

Features:

Simple and economic method if excessive caving does not occur. Therefore not suitable for

loose sand.

Major changes of soil character can be detected by means of penetration resistance.

These are 25mm to 75mm holes.

It requires fairly continuous sampling in stiff and dense soil, either to protect the sampler from

damage or to avoid objectionably heavy construction pit.

2. What is wash boring?

Ans- It is a popular method due to the use of limited equipments. The advantage of this is the

use of inexpensive and easily portable handling and drilling equipments. Here first an open hole

is formed on the ground so that the soil sampling or rock drilling operation can be done below

the hole. The hole is advanced by chopping and twisting action of the light bit. Cutting is done

by forced water and water jet under pressure through the rods operated inside the hole.

3. What is Auger boring?

Ans- This method is fast and economical, using simple, light, flexible and inexpensive

instruments for large to small holes. It is very suitable for soft to stiff cohesive soils and also can

be used to determine ground water table. Soil removed by this is disturbed but it is better than

wash boring, percussion or rotary drilling. It is not suitable for very hard or cemented soils, very

soft soils, as then the flow into the hole can occur and also for fully saturated cohesion less soil.

4. What is a Disturbed sample?

Ans-The structure of the soil is disturbed to the considerable degree by the action of the boring

tools or the excavation equipment’s.





The disturbances can be classified in following basic types:

Change in the stress condition

Change in the water content and the void ratio

Disturbance of the soil structure

Chemical changes,

Mixing and segregation of soil constituents

5. What are the undisturbed samplers?

Ans- It retains as closely as practicable the true in situ structure and water content of the soil.

For undisturbed sample the stress changes cannot be avoided. The following requirements are

looked for:

No change due to disturbance of the soil structure,

No change in void ratio and water content,

No change in constituents and chemical properties.





5 MARK QUESTIONS WITH ANSWERS

1. Write short notes on Augur boring and wash boring.

Ans. Auger Boring:

The examination of the sub-soil conditions for simple buildings to be erected in clayey or sandy

soil can be best performed by a post hole auger. The auger is held vertically and is driven into

the ground by rotating its handle by applying leverage. The auger is pressed down during the

process of rotation. At every 30 cm of depth penetrated, the auger is taken out and the samples

of the soils are collected separately for examination. This method can be conveniently used for

soil penetration up to 15 m depth. The types of augers commonly used are shown below. For

deeper holes or in grounds where gravel, boulders or comp act material is present, this method is

not adopted.

Shell and auger boring:

In this method different type of tools has to be adopted for boring. In case of soft to stiff clay,

cylindrical auger consisting of a hollow tube of 75 to 200mm in diameter with a cutting edge at

its bottom is used. In case of various stiff and hard clay, shells with cutting edge or teeth at

lower end are to be adopted while in case of sandy soil, shells or sand, pumps are used for

boring. By this method it is possible to make vertical boring up to 200 mm in diameter and 25 m

in depth by use of a hand rig. By use of mechanical rig it is possible to extend the depth of the

bore hole up to 50 m. The samples of the soil are recovered at regular intervals (or whenever

there is a change in strata) for conducting tests in laboratory for

Identification of soils and establishing properties of the sub-soil strata at various depths.





Wash boring:

For test boring over 3 meter in depth, this method can be conveniently used. In this method a

hollow steel pipe known as casing pipe or drive pipe is driven into the ground for a certain

depth. Then a pipe usually known as water jet pipe or wash pipe, which is shorter in diameter, is

lowered into the casing pipe. At its upper end, the wash pipe is connected to water supply

system while the lower end of the pipe is contracted so as to produce jet action. Water under

considerable pressure is forced down the wash pipe. The hydraulic pressure displaces the

material immediately below the pipe and the slurry thus formed is forced up through the annular

space between the two pipes. The slurry is collected and samples of material encountered are

obtained by settlement. In this process the particles of finer material like clay, loam etc. do not

settle easily and the larger and heavy particles of the soil may not be brought up at all.

Moreover, the exact position of a material in the formation cannot be easily be located. However

the change of stratification can be guessed from the rate of progress of driving the casing pipe as

well as the color of slurry flowing out. Yet the results obtained by wash boring process give

fairly good information about the nature of the sub-soil strata. This method can be adopted in

soft to stiff cohesive soils and fine sand

2. Explain SPT test in detail.





• Ans. Generally used for cohesion less soils

• To determine relative density , angle of shearing resistance, UCC

• A bore hole is made using drilling tools and a hammer of weight 63.5 falling from the height

of 750 mm at the rate of 30 blows/minute

• After reaching the specified depth, the drilling tool is replaced by a split spoon sampler to

collect soil sample.

• First 150 mm penetration is taken as seating drive and the no. of blows required for that

Penetration is discarded

• No of blows required for next 300mm penetration after seating drive is taken as standard

penetration number (N)

• No of blows greater than 50 are taken as refusal and the test is discontinued

• Corrections are applied to the observed N value.

• Correction to N value

Dilatancy Correction

Overburden correction

Of these, overburden correction is applied first and to that corrected value, dilatancy Correction

is applied.

Due to the presence of fine sand and silt below the water table, negative pore pressure develops

which increases, the observed N value. Hence correction is applied. (If N’<15 or

N=15, N’ = N)

Soils having the same relative density will show higher N value at greater depth due to presence





of over burden. Cohesion less soils are greatly affected by confining pressure. Hence N value is

corrected .σ <=280 kN/m2

3. Explain pressure meter test?

Ans. The pressure meter test is an in-situ testing method used to achieve a quick measure of the

in-situ stress-strain relationship of the soil. In principle, the pressure meter test is performed by

applying pressure to the sidewalls of a borehole and observing the corresponding deformation.

The pressure meter consists of two parts, the read-out unit which rests on the ground surface,

and the probe that is inserted into the borehole (ground). The original Ménard-type pressure

meter was designed to be lowered into a performed hole and to apply uniform pressure to the

borehole walls by means of inflatable flexible membrane. As the pressure increases, the

borehole walls deform. The pressure is held constant for a given period and the increase in

volume required for maintaining the constant pressure is recorded. A load-deformation diagram

and soil characteristics can be deduced by measurement of the applied pressure and change in

the volume of the expanding membrane.

The major difference between categories of pressure meter lies in the method f installation of the

instrument into the ground. Three main types of pressure meters are:

• The borehole pressure meter: The instrument is inserted into a performed hole.

• The self-boring pressure meter: The instrument is self-bored into the ground with the purpose

of minimizing the sol disturbance caused by insertion.

• Displacement pressure meters: The instrument is pushed into the ground from base of a

borehole. The soil displaced by the probe during insertion enters the body of instrument,

reducing the disturbance to the surrounding soil .

There are different approaches the interpretation of results and the determination of material

properties from pressure meter tests. In general, these approaches rely either on empirical

correlations to allow measured co-ordinates of pressure and displacement to be inserted directly

into design equations, or on solving the boundary problem posed by the pressure meter test.





3. What are the merits and demerits of split spoon sampler? Sketch a split spoon sampler and

explain its parts in brief?.

Ans. split-spoon samplers are used for taking samples for lithological descriptions, geotechnical

analyses that do not require undisturbed samples, and chemical analysis. The use of liners in

split-spoon allows collection of representative samples suitable for chemical analysis of all types

of contaminants. Spit-spoons consist of a barrel that is attached to a drive tip. Sampling is

accomplished by attaching the spit-spoon to the end of a DP extension, lowering it to the bottom

of a borehole, then driving it into the soil with a geotechnical hammer.

Advantages include: Easy to obtain samples in unconsolidated materials above 100ft.

• Produce very good-quality samples for both lithological description and chemical analysis.

• Relatively efficient and inexpensive at shallow and intermediate depths





4. Explain the Geophysical methods.

Ans. specializes in near-surface geophysics and utility locating services and is dedicated to

establishing strong client relationships. Sub Surface Survey’s extensive education and

experience in implementing state-of-the-art techniques allows for a more comprehensive

approach to solving complex problems through cost-effective means.

Subsurface Surveys, an applied geophysics company, uses a variety of geophysical methods to

solve engineering, geological, environmental and forensic problems. The methods and

instruments we use are chosen to meet the specific needs of our clients and accommodate the

existing field conditions.

Seismic Refraction:

Seismic refraction investigates the subsurface by generating arrival time and offset distance

information to determine the path and velocity of the elastic disturbance in the ground. The

disturbance is created by shot, hammer, weight drop, or some other comparable method for

putting impulsive energy into the ground. Detectors, laid out at regular intervals, measure the

first arrival of the energy and its time. The data are plotted in time – distance graphs from which

the velocities of the different layers, and their depths can be calculated. This sis possible because

rays ( a continuum points on the expanding wave front) of the disturbance wave follow a direct

route and is the first arrival energy at the close-in geophones. The rays are refracted across layer





boundaries where there is a difference in elastics and density properties. The critically refracted

ray travels along the layer interface, at the speed of the lower layer, and continuously “feeds”

energy back to the surface, to be successfully detected by the line of geophones. At some

distance the refracted ray becomes the first arrival.

Shot energy is normally collected at evenly spaced intervals throughout the entire length of the

line in order to increase coverage and generally determine whether or not the layering is

horizontal, dipping or undulating. The acquired data are computationally intense. A ray-tracing

computer program is used to iteratively honor all travel times and velocities, and to be able to

consider a large number of layers where they are present. A first energy arrival picking program,

with such features as zoom, filtering, time stretching, separation of traces, AGC and balancing

of traces, is also applied.

5. Write short notes on cone penetration test

Ans. Standard cone dimensions: tip 10 cm 2, sleeve 150 cm 2, 1.44-inch diameter Another

common configuration: tip 15 cm 2, sleeve 225 cm 2, 1.75-inch diameter 5, 10, 15-ton load

capacity cones most common .Tip resistance (q c ) . Sleeve friction (fs Sleeve friction (f ) s ) .

Induced pore pressure and pore pressure dissipation (U1,2,3 ) . Shear wave velocity Shear wave

velocity .Soil resistivity . Inclination .T empera ture

CPT - Continuous sampling, 1cm vertical resolution. Conservatively, 5 times faster than

traditional drilling. $6 to $9 per foot (NHCRP findings). Superior accuracy and precision

compared to typical drilling and testing drilling and testing. Predicts many design parameters

normally obtained by traditional drilling and sample testing. Laboratory sampling requirements

are greatly reduced for added cost savings. No drilling spoils are generated No drilling spoils are

generated. Does not eliminate the need for drilling and testing, but can gy g p reatl y reduce

number of borin gs/sam ples. Can collect additional data such as soil resistivity and shear wave

velocity with little added cost.





OBJECTIVE QUESTIONS WITH KEY

1. The standard penetration test is useful to measure

A. Shear strength of soft clays

B. Shear strength of sands

C. Consistency of clays

D. None of the above

2. For a undisturbed sample, the area ratio of the sample should be

A. Zero

B.10% or less

C. 10% to 20%

D. more than 20%

3. In-situ vane shear test is used to measure shear strength of

A. Very soft and sensitive clay

B. Stiff and fissured clays

C. Sandy soils

D. All the above

4. Select the incorrect statement

For a good quality soil sample

A. The area ratio should be low

B. The cutting edge should be thick

C. The inside clearance should be small

D. The outside clearance should be small

5. The height-diameter ratio for the in-situ vane is

A. 1.0

B. 1.50





C. 2.00

D. 3.0

6.The outside diameter of the tube may be between

A. 40-125 mm

B.35-95 mm

C. 45-130 mm

D. 50-100 mm

7.Electrical Profiling Method is also known as

A. Resistivity mapping method

B. Electrical sounding method

C. Electrical resistivity method

D. All the above

8. The Dutch cone has an Apex angle is

A. 500

B. 600

C. 650

D.700

9.The velocity of the shock waves increases as the depth from

A. V3>V1>V2

B. V2>V3>V1

C. V1>V2>V3

D. V3>V2>V1

10. Rotary drilling can be used in

A. clay, sand and rock

B. clays, silts and saturated sands





C. silts ,sand and rock

D. saturated sands, rock and silts

KEY

1 2 3 4 5 6 7 8 9 10

B B A B C A A B D A





FILL IN THE BLANKS

1. The seismic refraction methods are based on the principle of ____________________

2. Vane shear test is conducted to determine the ________________

3. The standard penetration test is the most commonly used _______ test.

4. In split-spoon sampler steel tube length is__________________

5. Sub-surface exploration are generally carried out in__________ stages.

6. A fully saturated soil is said to be____________________________

7. The types of soil is transported by gravitational forces are_________________________

8. A partially saturated soil is______________________________

9. Maximum size of clay particles, is_________________________________

10. . Cohesive soils are ______________________________________

KEY

1 2 3 4 5 6 7 8 9 10

Elastic

shock

wave

Shear

strength

of soil

In-situ

450

mm

3 two

phase

system

with

soil and

water

Talus

Three

phase

soil

0.002

mm

plastic and

also

compressible





UNIT 2


1. Define finite and infinite earth slopes with suitable examples.

Ans. If the slopes represents the boundary surface of infinite sil mass and the properties of the

soil at similar depth below the ground. It is termed as infinite slope.

Failure of infinite slope takes place due to sliding and the failure surface is parallel to the ground

plane.

Finite slopes

If the slopes are of final extent bounded by top and bottom surfaces, it is termed as finite slope.

Failure of the finite slopes takes place due to motion and the failure plane is either circular or

spiral.

2. What are the types of Failure slopes?

Ans. There are 5 types of slope failures

1. Rotational failure

2. Translational failure

3. Compound failure

4. Wedge failure

5. Miscellaneous failure

3. Write brief notes on Taylor’s stability number?

Ans. In this method Taylor’s stability curves or charts are used to read the taylor’s stability

number (Sn=C/rHc=Cm/rH)

For the given values of strength parameters of the soil

Fc=C/Cm





FH=Hc/H

The unit weight of the soil to be used in the above expression for the computation.

4. What is rotational slope failure and translational slope failure?

Ans. The slip surface is rotation along the downward and outward moment of soil mass is known

as rotational slope failure.

The failure surface is parallel to the ground surface .The shape of the failure surface is influenced

by the presence of any hard stratum at a shallow depth below the slope surface.

5. Write the formula for Bishops simplified method

Ans.






1. Define finite earth slopes with suitable examples?

Ans- A slope is an inclined boundary surface between air and the body of an earthwork such as

highways, cut or fill, railway cut or fill, earth dams, levees and river training works. The

stability of slope is one the most important one in civil engineering practice. A fairly common

engineering failure of slope is slipping of an embankment or cutting. The factor leading to

instability can generally be classified as

a)Those causing increased stress and

b)Those causing a reduction in strength.

2. Define infinite earth slopes with suitable examples?

Ans- The type of slope extending infinitely, or up to an extent whose boundaries are not well

defined. For this type of slope the soil properties for all identical depths below the surface are

same. In the making of natural slopes, their is no contribution from our side.

Natural slope: The slopes formed due to natural process and exist naturally are called natural

slopes. Natural slopes are those that exist in nature and are formed by natural causes. Such

slopes exist in hilly areas. The sides of cuttings, the slopes of embankments constructed for

roads, railway lines, canals etc and the slopes of earth dams constructed for storing water are

examples of manmade slopes. The slopes whether natural or artificial may be

Artificial slope: The slopes formed by unnatural process. Artificial slopes are formed by humans

as per requirements.

3. Discuss classification of slopes?

Ans- A number of classification system are available for analysis of slope stability. Some of the

most commonly referred classification system are :

Slope Mass Rating (SMR)

Chinese Slope Mass Rating System (CSMR)

Rock slope rating (RSR)

Slope stability rating (SSR)





Classification system, and Dump mass rating

4. What are types of slope failures?

Ans- Slope failures are major natural hazards that occur in many areas throughout the world.

Slopes expose two or more free surfaces because of geometry. Plane, wedge, toppling, rock fall

and rotational (circular/non-circular) types of failure are common in slopes (Figure 1). The first

four are more predominant in rock slopes and are primarily controlled by the orientation and the

spacing of discontinuities planes with respect to the slope face. The pattern of the discontinuities

may be comprised of a single discontinuity, or a pair of discontinuities that intersect each other,

or a combination of multiple discontinuities that are linked together to form a failure mode.

Circular and non circular failure occurs in soil, mine dump, heavily jointed or fractured rock

mass and very weak rock. The types of slope failure are primarily controlled by material

properties, water content and foundation strength.






1.

2.





3.





4.





5.






1. According to Coulomb's wedge theory, the active earth pressure slides the wedge

A. down and outwards on a slip surface

B. up and inwards on a slip surface

C. horizontal upward and parallel to base

D. horizontal inward and parallel to base.

2. If the failure of a finite slope occurs through the toe, it is known as

A. slope failure

B. face failure

C. base failure

D. toe failure.

3. Failure of the stability of slopes, generally occurs along

A. slip plane

B. a horizontal surface

C. a curved surface

D. all the surfaces.

4. The method of slice for the stability of slope

A. Can be used for stratified soil

B. Can be used when seepage occurs and the pore pressure exists within the soil

C. Given the factor of safety based on moments and not forces

D. All the above.

5. Taylor’s stability charts are based on the total stresses using the

A. Friction circle method

B. Method of slices

C. Φ=0 analysis


6. In stability analysis, the term mobilized shear strength is referred to as

A. Shear strength

B. Max. shear stress

C. Applied shear stress


7. Bishop’s simplified method of slices satisfies

A. Only the moments equilibrium

B. Only the vertical forces equilibrium

C. Only the horizontal forces equilibrium





D. All the statics equations

8. The factor of safety of an infinite slope in a sand deposit is 1.732. if the angle of shearing

resistance is 30, the safe slope is

A. 19.45

B. 75.4

C. 18.4

D. 71.6

9. Identify the incorrect statement

The stability of a slope is decreased by

A. Removal of a part of slope by excavation

B. Shock caused by a earthquake

C. Pore water pressure in the soil

D. Providing a berm at the toe

10. For the computation of N-component for sudden drawdown conditions by approximate

method, the weight is

A. Saturated unit weight

B. Submerged unit weight

C. Bulk unit weight

D. Dry unit weight

KEY

1 2 3 4 5 6 7 8 9 10

A D C D A C D C D B





Fill in the blanks

1. Bishop's method of stability analysis__________________

2. Skempton's pore pressure coefficient B for saturated soil is

3. The slip at critical angle, is generally known____________________

4. The slope of isochrone at any point at a given time indicates the rate of change

of__________________

5. Failure of a slope occurs only when total shear force is

6. The method of the slices is applicable to_____________________

7. For slopes of limited extent the surface of slippage, is usually along______________

8. For a base failure of a slope, depth factor___________________

9. Coulomb's wedge theory assumes that______________________________

10. An infinite slope is inclined at angle i and has its angle of internal friction φ, the stability

number Sa, is______________________________

KEY

1 2 3 4 5 6 7 8 9 10

assumes

the slip

surface

as an

arc of a

circle

1 slip

plane

pore

water

pressure

with

depth

greater

than

total

shearing

strength

MOHAR

CIRCLE

a

circular

arc.

Df

>1

back fill is

dry, cohesion

less,

homogeneous

and isotropic

(tan i

- tan

φ)

cos2

i





UNIT 3


1. Explain the earth pressure in active and passive and rest condition

Ans. Rest Condition: The lateral earth pressure is called at-rest pressure. When the soil mass is

not subjected to any lateral yielding.

Active Pressure: When the soil mass yields in such a way that it tends to stretch horizontally. A

retaining wall when moves away from the backfill.

Passive pressure: A state of passive pressure exits when the movement of the wall is such that the

soil tends to compress horizontally. The passive pressure develops on the left-side of the wall

below the ground level.

2. Explain the assumptions of Rankin’s theory?

Ans. Rankin considered the equilibrium of a soil element with in a soil mass bounded by a plane

surface. The following assumptions made by Rankin.

i) The soil mass is homogeneous and semi-infinite.

ii) The soil is dry and cohesion less

iii) The ground surface is plane, which may be horizontal or inclined.

iv) The back of the retaining wall is smooth and vertical.

v) The soil element is in a state of plastic equilibrium.

3. What are the different types of lateral earth pressures?

Ans. Lateral earth pressure can be grouped into 3 categories, depending up on the movement of

the retaining wall with respect to the soil retained.

i) At-rest pressure

ii) Active earth pressure





iii) Passive earth pressure

4. Different Types of Retaining walls?

Ans. On the basis of attaining stability, the retaining structures are classified into following:

i) Gravity walls

Ii) Semi Gravity Retaining Wall

Iii) Counterfort retaining wall

iv) Flexible walls

v) Free cantilever sheet pile

vi) Special type of retaining

5) Explain Gravity Walls?

Ans. Gravity walls are stabilized by their mass. They are constructed of dense, heavy materials

such as concrete and stone masonry and are usually reinforced.

Some gravity walls do use mortar, relying solely on their weight to stay in place, as in the case of

dry stone walls. They are economical for only small heights.






1. Explain the earth pressure in active and passive and rest condition

Ans. Rest Condition: The lateral earth pressure is called at-rest pressure. When the soil mass is

not subjected to any lateral yielding.

Active Pressure: When the soil mass yields in such a way that it tends to stretch horizontally. A

retaining wall when moves away from the backfill.

Passive pressure: A state of passive pressure exits when the movement of the wall is such that the

soil tends to compress horizontally. The passive pressure develops on the left-side of the wall

below the ground level.

2. Explain the assumptions of Rankin’s theory?

Ans. Rankin considered the equilibrium of a soil element with in a soil mass bounded by a plane

surface. The following assumptions made by Rankin.

i) The soil mass is homogeneous and semi-infinite.

ii) The soil is dry and cohesion less

iii) The ground surface is plane, which may be horizontal or inclined.

iv) The back of the retaining wall is smooth and vertical.

v) The soil element is in a state of plastic equilibrium.

3. What are the different types of lateral earth pressures?

Ans. Lateral earth pressure can be grouped into 3 categories, depending up on the movement of

the retaining wall with respect to the soil retained.

i) At-rest pressure

ii) Active earth pressure

iii) Passive earth pressure





4. Different Types of Retaining walls?

Ans. On the basis of attaining stability, the retaining structures areclassified into following:

i) Gravity walls

ii) Semi Gravity Retaining Wall

iii) Counterfort retaining wall

iv) Flexible walls

v) Free cantilever sheet pile

vi) Special type of retaining

5. Explain Gravity Walls?

Ans. Gravity walls are stabilized by their mass. They are constructed of dense, heavy materials

such as concrete and stone masonry and are usually reinforced.

Some gravity walls do use mortar, relying solely on their weight to stay in place, as in the case of

dry stone walls. They are economical for only small heights.






1. Design requirement of retaining wall?

Ans.

No Sliding

Horizontal forces tend to slide the wall away from the fill. This tendency is resisted by friction at

the base. = Coefficient of friction between the base of the wall and soil (= tan ).

= Sum of the all vertical forces i.e. vertical component of inclined active force.

A minimum factor of safety of 1.5 against sliding is recommended.

No Overturning





should be less than the Safe bearing capacity( ) of the soil & should not be Tensile in any case.

Tension is not desirable. The tensile strength of the soil is very small and tensile crack would

develop. The effective base area is reduced.

2. What is the Design Requirement for Gravity walls

Ans. Gravity Retaining walls are designed to resist earth pressure by their weight. They are

constructed of the mass, concrete, brick or stone masonry. Since these materials can not resist

appreciable tension, the design aims at preventing tension in the wall. The wall must be safe

against sliding and overturning. Also the maximum pressure exerted on the foundation soil

should exceed the safe bearing capacity of the soil.

So before the actual design, the soil parameters that influence the earth pressure and the bearing

capacity of the soil must be evaluated. These include the unit weight of the soil, the angle of the

shearing resistance, the cohesion intercept and the angle of wall friction. Knowing these

parameters, the lateral earth pressure and bearing capacity of the soil determined.





3. What is Coulomb’s Theory of Earth Pressure?

Ans.

Assumptions;

The backfill is a dry, cohesion less, homogeneous, isotropic soil.

The backfill surface is planar and can be inclined.

The back of the wall can be inclined to the vertical.

The failure surface is a plane surface which passes through the heel of the wall.

The position and the line of action of the earth pressure are known.





The sliding wedge is considered to be a rigid body and the earth pressure is obtained by

considering the limiting equilibrium of the sliding wedge as a whole.

4. What are the limiting values of the lateral earth pressure at a depth of 3 meters in a uniform

sand fill with a unit weight of 20 KN/m3 and a friction angle of 35°? The ground surface is level.

If a retaining wall with a vertical back face is interposed, determine the total active thrust and the

total passive resistance which will act on the wall.





5. A retaining wall, 7.5 m high, retains a cohsionless backfill. The top 3 m of the fill has a unit

weight of 18 kN/m3 and φ = 30° and the rest has unit weight of 24 kN/m3 and φ = 20°.

Determine the pressure distribution on the wall.





OBJETIVE QUESTIONS WITH KEY

1. A shallow foundation is usually defined as a foundation which has

A. Depth less than 0.6 m

B. Depth less than its width

C. Depth less than 1.0 m


2. The allowable soil pressure for foundation in chosive soils is generally controlled by

A. Settlements

B. Bearing capacity

C. Both a & b

D. Neither a nor b

3. The bearing capacity of soil supporting a footing of size 3m*3m will not be affected

by the presence of water table located at a depth below the base of footing of

A. 1.0

B. 1.50m

C. 3.0m

D. 6.0m

4. The permissible settlement is the maximum in the case of

A. Isolated footing on clay

B. Raft on clay

C. Isolated footing on sand

D. Raft on sand

5. A pile foundation is used when

A. The loads are heavy

B. The soil stratum near ground surface is weak

C. Both a&b

D. Neither a nor b

6. The load bearing capacity of a pile depends upon the

A. Skin friction

B. Point resistance

C. Both a & b

D. Neither a nor b

7. The negative skin friction on a pile develops when

A. The soil in which it is driven is sandy soils

B. The soil surrounding it settles more than the pile

C. The ground water table rises

D. The soil near the tip is clay

8. The group efficiency of driven piles in sand at a close spacing may be

A. Equal to 100%

B. Greater than 100%

C. Well below 100%


9. Pile foundations are generally preferred to for





A. bridge foundations

B. sky scrapper buildings

C. residential building

D. runways

10. The maximum pressure which a soil can carry without shear failure, is called

A. safe bearing capacity

B. net safe bearing capacity

C. net ultimate bearing capacity

D. ultimate bearing capacity

KEY

1 2 3 4 5 6 7 8 9 10

B B C B C C B B B A





FILL IN THE BLANKS

1. Contact pressure beneath a rigid footing resting on cohesive soil is

2. In the plate loading test for determining the bearing capacity of soil, the size of square

bearing plate should be

3. Terzaghi's bearing capacity factors Nc, Nq and Nr are functions of

4. Terzaghi's general bearing capacity formula for a strip footing

5. The rise of water table below the foundation influences the bearing capacity of soil mainly by

reducing

6. Allowable bearing pressure for a foundation depends upon

7. The bearing capacity of a soil depends upon

8. The pressure that builds up in pore water due to load increment on the soil, is termed

9. Tergazhi's theory of one dimensional consolidation assumes

10. Negative skin friction on piles

KEY

1 2 3 4 5 6 7 8 9 10

more at

edges

compar

ed to

middle

betwe

en

300

mm

and

750

mm

angle

of

intern

al

fricti

on

only

ultima

te

bearin

g

capaci

ty

cohesi

on and

effecti

ve unit

weight

of soil

both

allowab

le

settlem

ent and

ultimat

e

bearing

capacit

y

interna

l

friction

al

resista

nce of

particle

s

exces

s pore

pressu

re

Darcy

’s law

for the

velocit

y of

flow

of

water

throug

h soil,

is

perfec

tly

valid

is

caused

due to

relative

settlem

ent of

the soil





UNIT-4


1. What are the Different types of footings?

Ans. There are 2 types of footings.

1. Shallow footings (D<B)

2. Deep footings (D>B)

Shallow footings are also divided into 2 types

1. Raft foundation

2. Footings

Deep foundations are also divided into 2 types

1. Pile foundation

2. well foundation

2. Differentiate between uniform settlement and differential settlement

Ans. Differential or uneven settlement occurs when the soil beneath a structure can not bear the

weights imposed. The settlement of a structure is the amount that the structure will “sink” during

and after construction. Differential settlements become a big problem when the foundation settles.

3. Make a note on initial and consolidation settlement.

Ans. Settlement deals with the sinking of structure due to compression of soil. As per IS code, the

following types of settlements are reported:

1. Total settlement:- it is combination of initial and consolidation settlement Elastic settlement/

initial settlement:- initial/elastic settlement is the settlement caused due to elastic properties of the

soil due to applied load. Consolidation settlement - Primary consolidation: - is the consolidation

occurs due to the expulsion of air from the voids. Secondary/creep:- is the consolidation due to

expulsion of water from the voids.

2. Differential settlement/ angular distortion:- it is the difference in settlement between two points

below the footing.





3. Time dependent settlement For sands, settlement is called immediate settlement as it is the major

settlement, there being no or very less consolidation settlement. For clays, we talk about initial or

elastic settlements and not immediate settlements.

4. Define pile foundation. When are pile foundations preferred?

Ans. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into

the ground at the building site.

Pile foundation is required when the soil bearing capacity is not sufficient for the structure to

withstand. This is due to the soil condition or the order of bottom layers, type of loads on

foundations, conditions at site and operational conditions.

5. Explain the settlement analysis of piles in short.

Ans. The settlement of a pile under a vertical working load, , is caused by three factors:

𝑠 = 𝑠1 + 𝑠2 + 𝑠3

Where s= Total settlement of the pile

S1= Elastic settlement of the pile

S2= Settlement of the pile caused by the load at the pile tip

S3= Settlement of the pile caused by the load transmitted along the pile shaft.






1. What are the Different types of footings?

Ans. There are 2 types of footings.

1. Shallow footings (D<B)

2. Deep footings (D>B)

Shallow footings are also divided into 2 types

1. Raft foundation

2. Footings

Deep foundations are also divided into 2 types

1. Pile foundation

2. well foundation

2. Differentiate between uniform settlement and differential settlement

Ans. Differential or uneven settlement occurs when the soil beneath a structure can not bear the

weights imposed. The settlement of a structure is the amount that the structure will “sink” during

and after construction. Differential settlements become a big problem when the foundation settles.

3. Make a note on initial and consolidation settlement.

Ans. Settlement deals with the sinking of structure due to compression of soil. As per IS code, the

following types of settlements are reported:

1. Total settlement:- it is combination of initial and consolidation settlement Elastic settlement/

initial settlement:- initial/elastic settlement is the settlement caused due to elastic properties of the

soil due to applied load. Consolidation settlement - Primary consolidation: - is the consolidation

occurs due to the expulsion of air from the voids. Secondary/creep:- is the consolidation due to

expulsion of water from the voids.

2. Differential settlement/ angular distortion:- it is the difference in settlement between two points

below the footing.

3. Time dependent settlement For sands, settlement is called immediate settlement as it is the major

settlement, there being no or very less consolidation settlement. For clays, we talk about initial or

elastic settlements and not immediate settlements.





4. Define pile foundation. When are pile foundations preferred?

Ans.A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into

the ground at the building site.

Pile foundation is required when the soil bearing capacity is not sufficient for the structure to

withstand. This is due to the soil condition or the order of bottom layers, type of loads on

foundations, conditions at site and operational conditions.

5. Explain the settlement analysis of piles in short.

Ans.The settlement of a pile under a vertical working load, , is caused by three factors:

𝑠 = 𝑠1 + 𝑠2 + 𝑠3

Where s= Total settlement of the pile






1. Explain the Static method for Estimating the load carrying capacity of a single pile driven in

cohesive soil (Clay)

Ans. Ultimate bearing capacity of a pile is determined by the formula given below;

Qd= Rf + Rp= Asrf + Aprp

Where, Rf = total ultimate skin friction

Rp= total ultimate point or end bearing resistance

As= surface area of pile upon which the skin friction acts

Ap= area of cross section of pile on which bearing resistance acts

rf = average skin friction

rp= unit point or toe resistance

A FOS 2.5 or 3 may be adopted for finding the allowable load.

2. Explain the Dynamic formulae for Estimating the load carrying capacity of a single driven

pile

Ans. There are two different types of methods for calculating the dynamic pile formula

Engineering News formula

Hiley’s formula

Engineering News formula:

Proposed by A.M. Wellington in the following general form;

Qa= WH/F(S+C)

Where, Qa= allowable load W= wt. of the hammer H= height of the fall

F= F.O.S, taken as “6”

S= final set (penetration) C= empirical constant 2.5 for drop hammer,& 0.25 for single and double

acting hammers.





Drop hammer:

Qa= WH/6(S+2.5)

Single acting steam hammer:

Qa= WH/6(S+0.25)

Double acting steam hammer:

Qa= (W+a.p)H/6(S+0.25) Where, a= effective area of a piston

p= mean effective steam pressure

Hiley’s formula:

IS: 2911 gives the following formula based on the original expression of Hiley:

Qd=𝜼𝒉WH𝜼𝒃/(𝑺+𝑪/𝟐)

Where, Qd= ultimate load on a pile

C= total elastic compression

C = C1+C2+C3, temporary elastic compression of dolly and packing, pile & soil respectively.

𝜼𝒉 = efficiency of hammer

𝜼𝒃=efficiency of hammer blow (i.e. ratio of energy after impact to striking energy of ram)

𝜼𝒃 =W+e2P/W+P for W>eP

𝜼𝒃=W+e2P/W+P−(W−eP/W+P)^2, for W<eP

Where, P= wt. of a pile, helmet, follower

e= coefficient of restitution (0 to0.5)

Allowable load is obtained by using F.O.S 2 or, 2.5.

3. What are the effects of pile driving?

Ans. The installation of piles or sheet piles can cause damage to buildings or other structure on the

ground. Frequently, such damage is attributed to vibrations of the building itself.Many countries

have national or international standards for assessing the risk of vibratin damage to buildings.





Science these standards are often prepared by engineers with little to no geotechnical knowledge,

the effects of ground. Conditions on vibration propagation and damage to building foundations are

generally not recognized. In addition damage criteria based solely on the dynamic response of

buildings neglect the importance of damage mechanisms governed by geotechnical conditions. One

potentially important damage mechanism is differential settlement below buildings, especially when

they are founded on loose granular soils. When seeking guidance in geotechnical lecture, little to no

information can be found regarding methods to asses permissible levels of ground vibrations with

respect to risk for settlement.

4. Explain how the Group capacity of piles can be found by different methods

Ans. The pile capacity may be calculated from the results of in-situ standard penetration test. Here

the empirical formulas are applied for determining the point resistance whereas the shaft resistance

is found from the standard penetration number (N). Alternative method can be by using the static

formulas after determining the N-value, since this value is related to the angle of shearing

resistance. The cone penetration tests may be used to calculate the pile capacity.





Pile load tests:

It is the most reliable and efficient method for estimation of pile capacity. Here the test pile is

embedded and then loaded to failure. The pile capacity is related to the ultimate load or the load at

which the settlements do not exceed the permissible limits

To obtain back-figured soil data that will enable other piles to be designed.

To confirm pile lengths and hence contract costs before the client is committed to over all job costs.

To counter-check results from geotechnical and pile driving formulae

To determine the load-settlement behavior of a pile, especially in the region of the anticipated

working load that the data can be used in prediction of group settlement.

To verify structural soundness of the pile.

5. A concrete pile, 9m long, was driven by a single acting Vulcan Hammer with rated energy

35.26 KJ. The total settlement as recorded for the last 10blows was 2.5 mm/blow. Using

Engineering News formula, calculate the pile capacity.

Ans. Qa=(166.64E/s+2.54)





E=35.26 KJ

S=2.5 mm/ blow

Qa=(166.64E/s+2.54)

Qa= (166.64*35.26)/(2.5+2.54)

=1165.82 K






1. A shallow foundation is usually defined as a foundation which has

A. Depth less than 0.6 m

B. Depth less than its width

C. Depth less than 1.0 m


2. The allowable soil pressure for foundation in chosive soils is generally controlled by

A. Settlements

B. Bearing capacity

C. Both a & b

D. Neither a nor b

3. The bearing capacity of soil supporting a footing of size 3m*3m will not be affected by the

presence of water table located at a depth below the base of footing of

A. 1.0

B. 1.50m

C. 3.0m

D. 6.0m

4. The permissible settlement is the maximum in the case of

A. Isolated footing on clay

B. Raft on clay

C. Isolated footing on sand

D. Raft on sand

5. A pile foundation is used when

A. The loads are heavy

B. The soil stratum near ground surface is weak

C. Both a&b

D. Neither a nor b

6. The load bearing capacity of a pile depends upon the

A. Skin friction

B. Point resistance

C. Both a & b

D. Neither a nor b

7. The negative skin friction on a pile develops when

A. The soil in which it is driven is sandy soils

B. The soil surrounding it settles more than the pile

C. The ground water table rises

D. The soil near the tip is clay

8. The group efficiency of driven piles in sand at a close spacing may be





A. Equal to 100%

B. Greater than 100%

C. Well below 100%


9. Pile foundations are generally preferred to for

A. bridge foundations

B. sky scrapper buildings

C. residential building

D. runways

10. The maximum pressure which a soil can carry without shear failure, is called

A. safe bearing capacity

B. net safe bearing capacity

C. net ultimate bearing capacity

D. ultimate bearing capacity

KEY

1 2 3 4 5 6 7 8 9 10

B B C B C C B B B A





FILL IN THE BLANKS

1. Contact pressure beneath a rigid footing resting on cohesive soil is

2. In the plate loading test for determining the bearing capacity of soil, the size of square bearing

plate should be

3. Terzaghi's bearing capacity factors Nc, Nq and Nr are functions of

4. Terzaghi's general bearing capacity formula for a strip footing

5. The rise of water table below the foundation influences the bearing capacity of soil mainly by

reducing

6. Allowable bearing pressure for a foundation depends upon

7. The bearing capacity of a soil depends upon

8. The pressure that builds up in pore water due to load increment on the soil, is termed

9. Tergazhi's theory of one dimensional consolidation assumes

10. Negative skin friction on piles

KEY

1 2 3 4 5 6 7 8 9 10

more at

edges

compare

d to

middle

betwee

n 300

mm

and

750

mm

angle

of

intern

al

frictio

n only

ultimat

e

bearin

g

capacit

y

cohesio

n and

effectiv

e unit

weight

of soil

both

allowabl

e

settleme

nt and

ultimate

bearing

capacity

internal

frictiona

l

resistan

ce of

particles

excess

pore

pressur

e

Darcy’

s law

for the

velocit

y of

flow of

water

through

soil, is

perfectl

y valid

is

caused

due to

relative

settleme

nt of the

soil





UNIT 5


1. What are the types of caisson foundations?

Ans. Caissons are of three types.

i) Open caissons

ii) Box caissons

iii) Pneumatic caissons

2. Write a short note on open caisson foundation.

Ans. The top and bottom of the caisson is open during construction. It may have any shape in plan.

It has a cutting edge which is fabricated at the site and the first segment of shaft is built on it. The

soil inside the shaft is dredge by suitable means and another segment added to it. The process of

sinking is continued thus till it reaches the required depth.

3. Explain the process of well sinking.

Ans. The following operation is carried out while sinking the caisson excavate material under the

excavate material under the inside of the well curb mechanically or manually. Allow the well to

remain vertical, Up to a depth of 1 m, excavation underwater can be made manually when the depth

of water exceeds 1m excavate by grabs, When well goes on sinking skin friction increases and

weight of well decreased due to buoyancy. When the well does not sink, sunk by applying Kent

ledge. If this operation is not sufficient jet outside the well.

4. Determine the well foundation components.

Ans. These are the components

i) Well cap

ii) Staining

iii) Curb

iv) Cutting edge

v) Bottom plug

vi) Dredge hole





vii) Top plug

5. Discuss the various types of shapes of well foundations.

Ans. These are the components.

i) Circular well

ii) Double D-well

iii) Dumb-bell









1. What are the types of caisson foundations?

Ans. Caissons are of three types.

4 Open caissons

5 Box caissons

6 Pneumatic caissons

2. Write a short note on open caisson foundation.

Ans. The top and bottom of the caisson is open during construction. It may have any shape in plan.

It has a cutting edge which is fabricated at the site and the first segment of shaft is built on it. The

soil inside the shaft is dredge by suitable means and another segment added to it. The process of

sinking is continued thus till it reaches the required depth.

3. Explain the process of well sinking.

Ans. The following operation is carried out while sinking the caisson excavate material under the

excavate material under the inside of the well curb mechanically or manually. Allow the well to

remain vertical, Up to a depth of 1 m excavation underwater can be made manually when the depth

of water exceeds 1m excavate by grabs, When well goes on sinking skin friction increases and

weight of well decreased due to buoyancy. When the well does not sink, sunk by applying Kent

ledge. If this operation is not sufficient jet outside the well.

4. Determine the well foundation components.

Ans. These are the components

i) Well cap

ii) Staining

iii) Curb

iv) Cutting edge

v) Bottom plug

vi) Dredge hole





vii) Top plug

5. Discuss the various types of shapes of well foundations.

Ans. These are the components.

i) Circular well

ii) Double D-well

iii) Dumb-bell









1. Explain Stability Analysis of Well Foundations?

Ans. A well foundation supporting a bridge pier is subjected to vertical and horizontal forces. The

various forces acting on the well are

Self-weight of the well and its superstructure

Live loads

Water currents and buoyancy

Temperature, wind and earth quake

Breaking and tracking forces

Resistance of the well walls

Base and skin friction

Terzaghi (1943) gave an approximate solution based on the analysis of the free rigid bulk. Resolve

all forces in vertical direction and obtain the resultant PV.

Resolve the forces in two horizontal directions i.e along and across the pier and get the values of PB

and PL.

.





The resultant vertical force PV and the resultant horizontal force PB are considered for analysis. The

forces and earth pressure distribution acting on the well are shown in the figure. Pressure at any

depth z below the scour level is p z(Kp Ka) zK '

2. What are the Causes of Tilts and Shifts

Ans. No uniform bearing capacity

Obstruction on one side of the well

Sand blowing in wells during sinking. It will cause sudden sinking of well

Method of sinking: Material should be removed from all sides equally otherwise the well may

experience tilt

Sudden sinking due to blasting may also cause tilting of well

Irregular casting of staining will cause less friction on one side leads to chances of tilting of well.





3. What are the forces acting on the well foundation?

Ans. The following forces should be considered n the design of a well foundation.

1. Dead load: The dead loads carried by the well include the weight of the superstructure and the

self-weight.

2. Live load: The design live loads for railway bridges are taken according to IRBR.For road

bridges, the live loads as specified by the Indian road congress standard specifications and code of

practice for road bridges.

3. Impact loads: The effect due to live load is considered only in the design of pier cap and the

bridge seat on the abutment.

4. Wind loads: Wind loads are randomly applied dynamic loads. The intensity of the wind

pressure on the surface of a structure depends on wind velocity, air density, orientation of the

structure, area of contact surface, and shape of the structure. Because of the complexity involved in

defining both the dynamic wind load and the behavior of an indeterminate steel structure when

subjected to wind loads, the design criteria adopted by building codes and standards have been based

on the application of an equivalent static wind pressure.

5. Water pressure: Pressure is the force that pushes water through pipes. Water pressure

determines the flow of water from the tap. The amount of pressure at your tap can depend on how

high the service reservoir or water tower is above your home, or on how much water other customers

are using.

6. Longitudinal Forces: The plane perpendicular to the rotational axle of the wheel. The force

perpendicular to this plane and in parallel to the rotational axle is called lateral force (Fy). The

characteristic value for the lateral force ist the lateral slip angle (alpha) (also called side slip angle)

which is defined as the angle between the wheel main plane and the direction of the wheel center

velocity

7. Centrifugal forces: The concept of the centrifugal force can be applied in rotating devices,

such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in

centrifugal railways, planetary orbits and banked curves, when they are analyzed in a rotating

coordinate system. The term has sometimes also been used for the reactive centrifugal force that is a

reaction to a centripetal force.

8. Buoyant forces: The buoyant force comes from the pressure exerted on the object by the

fluid. Because the pressure increases as the depth increases, the pressure on the bottom of an object is

always larger than the force on the top - hence the net upward force. The buoyant force is present

whether the object floats or sinks.

9. Earth pressure: Earth pressure is the lateral pressure exerted by the soil on a shoring system.

It is dependent on the soil structure and the interaction or movement with the retaining system.





4. What are the sinking operations of well foundations

Ans. Erect the cutting edge

Erect inside shuttering of curb.

Fix reinforcement for the curb.

Erect outside shuttering of curb.

Concrete the curb and ground it.

Remove the shuttering.

Fix reinforcement in staining

Erect reinforcement for one lift.

Concrete the staining

Dredge inside the well

Sink the well in stages.

Sinking is done by uniform excavation of material.

Use of water jetting and explosives may be done.

Normally dewatering should not be done.

Tilts must be rectified wherever necessary.

5. What are the advantages of well foundation?





Ans.






1. Well foundation is a type of

A. Open caisson

B. Pneumatic caisson

C. Floating caisson

D. Drilled pier

2. The grip length below the maximum scour level for the railway bridges is usually

A. 0.5 R

B. 0.25 R

C. R

D. 2 R

3. In some well foundation, the following is not provided

A. R.C.C. well cap

B. Top plug

C. Bottom plug

D. Curb

4. The most commonly used shape of a well foundation is

A. Double –D well

B. Circular well

C. Double octagonal well

D. Rectangular well

5. The thickness of staining for railway bridges is usually kept the outside diameter is

A. One-eight

B. One tenth

C. One sixth

D. One fourth

6. The common type of wells are

A. Rectangular

B. Dumb bell

C. Single circle

D. All the above

7. Well are also called as





A. Open caisson

B. Shell sunk

C. Caisse

D. All of the maintained

8. The choice of a particular shape of a well depends on

A. Dimension of the base and cost of sinking

B. Types of soil condition

C. None of the above

D. All of the above

9. What are the types of caissons that can be used as a foundation?

A. Box caissons and Open caissons

B. Closed caissons

C. None of the mentioned

D. All of the mentioned

10. The inside shuttering of the well curb is made up of_________

A. Steel

B. Wood

C. Brick masonry

D. Concrete

KEY

1 2 3 4 5 6 7 8 9 10

A A B B D D A A A C





FILL IN THE BLANKS

1. _______________________caissons, permits excavation in dry?

2. The sinking of the dredge is uniform ______________________shapes of well.

3. The components that are needed to be considered in designing of a well foundations

is_______

4. A disadvantage in using circular shape of well foundation is___________

5. The most economical shape, of a well for construction of large pier is_____

6. For alluvial soil, the normal scour depth can be calculated by___________ formula.

7. The grip length of well is taken as_________ below the scour level in roads.

8. For piers and abutment, the minimum depth of embedment below the scour level should be

taken as _________m.

9. The analysis of well foundation is done based on the assumptions of_________

10. The maximum depth of scour at the nose of pier is_______ the Lacey’s value.

KEY

1 2 3 4 5 6 7 8 9 10

Pneumati

c caissons

Circula

r

Botto

m plug

Diamete

r of well

is more

than

required

Double

-D

Lacey’

s

formul

a

1/

3

R

2.

0

Banerjee and

Gangopadhya

y

Twic

e

course file on foundation engineering by ch.hari...

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