HFJXxSJb9sI_transcript.txt

Let us talk about the course content, so let
me ask you a question, what are your expectations
from this course, how many mechanics courses
you have done? Introduce yourself, my name
is Adhithya, Adhithya, yes, there will be
so many Adhithyas in the class, so Adhithya
Upadhaya, Adhithya Upadhaya, yes, my question
is what you did not learn over here, which
forces you to study geotechnical engineering-I
which is also known as soil mechanics.
Soil properties, ok, so let us complete this
list first and then this is with a ways soil
mechanics alright, which is the modern name
is geotechnical engineering-I. yeah, you are
saying something Adhithya. So, in this course
we never learned about the soil properties
on what the structures are built or how the
fluid is going to get affected by the soil.
Sorry sorry say it again how, on what the
structures are built or the water the fluid
how it flows and what kind of soil very nice
never learnt everything.
So, you already read everything, what are
your expectations, Sir I am Shishanka Shashanka
Shashan Shashanka. Yes. So like this stability
of structures are generally dependent on how
the soil is below it, so, okay, it is important,
okay and sorry, since the stability of any
structure which is above it depends also on
the soil properties. So it is important to
learn soil mechanics. Yes next, My name is
Yesh sorry Yesh Yesh. Okay.
Sir the expectations are pretty much same.
Sorry speak clearly. how soil behaves, when
it is exposed to water. How soil behaves,
how water transmits through it. How water
transmits through it, alright. So the property
like how much strength can be a how much strength
very good and nice. My name is Rohit Choudhary.
Yes. I think that for any structure this course
will help us to determine the type of foundation
.
We are going to who who, who have you this
idea of foundations and all, means depending
upon the soil we will choose the type of foundation,
where you are much much ahead of your time.
You understand see right now you have to understand
the soils. But that is a good application
of what you're going to study over here foundations
alright. So as some of you was talking about
the stability of structures and all.
These things will come much later. This is
the time to learn A B C of a new material.
So that is why what I have done is I have
listed materials as number 1. You see, you
were talking about fluid mechanics, structural
mechanics, solid mechanics, engineering mechanics.
Truly speaking it should have been an inverted
pyramid, so currently we are doing structural
mechanics-II. Forget about what you are doing
what exist what should be aware of.
Think about it next. Hmm. Your name at least
tell your name. I am Shanthanu Chaparia. Okay.
I am aware of this much courses only as of
now. Biomechanics. Is this okay, yeah. It
is becoming very contemporary. Is this correct
or not, why. Everybody is talking about biomechanics,
bio molecular mechanics, this is correct?
So, let me tell you that civil engineers are
not much behind all these things.
So, once you understand the material we can
talk about all these things also later on.
So, if you go to the web pages of some of
the faculty members in the department, they
are all active in these subjects, any other
things which comes to mind nanomaterials,
nano mechanics, you are from IIT Bombay, is
it not, IIT Bombay is famous for what, nano
center, nano center clear. So, nano mechanics
of everything.
Now, let me ask you a question. What is so
common between nanomaterial and soils. Any
guess, Mahima, yes, please. Both are small
particles, both are small particles correct,
how small they are. What is meant by nano?
any example of soil which you think is a nanoparticle?
Next, I am Poornima, yes, sea sand, see particle,
next much lower in a particle size range as
compared to sands.
My name is Aniket. Aniket, yes. I also do
not know sir okay, very good. Not knowing
is not crime, myself Subam Sujith. Maybe straight
away myself Subam Sujith Subam. Yes. Okay.
Maybe mud so tight, very good. So mud is a
layman's language, can you refine your answer?
what is mud, quite close, clay, very good
excellent. So, clays are the nanomaterials.
So what is that I am trying to draw a similarity
between.
Yeah. Hi, my name is Aksath, Aksath. Yes,
yes Aksath what is the similarity I am trying
to draw between the nanomaterials which you
normally talk about in material sciences,
electronics and now my question is why I am
discussing this in the class, which has meant
for Civil Engineers. May be the properties
of nanomaterials can be the same, clays themselves
or in nanomaterial.
Okay, so by studying the properties of clay,
we can have some civil engineers are the first
to talk about the nanomaterials you know in
the history of civilization. And much later
came the application in the field of electronics
and other fields, this is the message which
I am trying to give you. Okay, so well you
are right most of you anything which I have
left over here or you have left over here
which you want to include, yes Ankit.
So, maybe sir different types of soil in its
properties, no, no, you were talking about
you know, what is that you are interested
in knowing about it. So that we should study
the mechanics of the soils, which is geotechnical
engineering I. Anything which we have missed
out in this series, it was talking about the
material somebody was talking about structures
resting on the somebody was talking about
the transmissivity, fluid passing through
this alright, then somebody was talking about
this strength, and so on. And this guy started
talking about the foundations and then I stopped
them over there. I said, no, the size of this
application part of it, alright, you are getting
the point. So, right now, what we are more
interested in is the material itself. Now,
as an engineer as a technologist, slowly and
slowly you will start realizing what is the
difference between engineers and technologists.
So why IIT Bombay gives you B.Tech and another
institution gives you BE is a big question.
And what should be your role as a B.Tech degree
holder. I am sure you have not question this
ever. So today evening when you go back, please
check it out, clear. So, the funda here is
right now we will just understand with whom
I am interacting, who is Mannan, interaction,
whatever interaction I have to understand
the material first clear, and then only I
will jump on to whatever foundations I have
to provide whatever structures I have to create.
What type of transmissivity I am going to
talk about and so on, that will come much
later. So first of all, what you have to do
is just understand the material. So most of
the emphasis would be to explain to you the
material with which you are going to communicate
what is the meaning of this word communication
with the material. My name is Arpan Jain say,
say it again Arpan, Arpan yes. So what is
the meaning of the word communication with
the material.
Now with the properties very good. So, communication
means the way you want to talk to any of your
friends. You do not have a name first of all,
you do not know from where the material has
come, this guy has come, what is the history
clear, and then you want to understand why
he or she is here. And then you want to understand
how I should be approaching and talking and
then further on, how I should be communicating.
And then maybe utilizing the person, are you
getting this feeling. So, the whole idea of
teaching geotechnical engineering I is to
make you conversant with the material which
you have known. Everybody is born out of soils.
But you have never thought about it as a technologist,
as an engineer, you have never tried to communicate
with it. Now, if you travel from this place
to your hostels, and you must be noticing
because of the rains, how many grams, kilograms
and tons of soil is getting washed out, because
of the rains from the Gymkhana.
Now, this is a good example of transmissivity
which you were talking about, now if this
happens inside a dame imagine what is going
to happen are you getting the point. So, we
would like to understand the material first
and then we will slowly and slowly start communicating
with it and then what stage will come after
communication, what stage comes you start
commanding, dictating.
And then what comes later on negotiation,
you understand the difference between these
words. So, the day you start negotiating with
the material, you have become an extreme expert
in the subject. So, somebody says that I cannot
do anything with this material. You said no,
no, no, it is not like that. I will, what
I will negotiate with the material that you
have to behave like this the way I want you
to are you getting this idea clear.
A good example would be you are developing
so many fourth, fifth, sixth cities in Mumbai
you know reclamation, we will be talking about
that later on. That means, neither the soil
was from the local place, you brought it from
somewhere else. You started dictating it,
how should behaving, and then a stage came
when you started negotiating with it, the
look, you have to be stable here for 30 years,
50 years, 60 years.
I going to load you from the top, you are
not supposed to deform at all, even if the
waves come, you should remain like this. Is
this part clear, any questions. So, modern
day soil mechanic when I studied, I studied
this maybe I do not know how many years back
I am 86 pass out. So 1982, 83-84, 1984 I must
have studied solid mechanics. Those days the
subject was more of bookish. But now things
have changed.
Everything has a practical connotation, everything
has a practical meaning, application for what
are you studying in the classroom. Unless
you have understood and application of it,
you should stop the instructor. And ask the
question that I am not very clear about what
is the implication of what to say. So, my
intention would be, if you help me to make
you a technologist of a very special material,
which is known as soils.
And of course, the genesis of soil also we
will study, that means, we will not only talk
about the how to deal with the offsprings,
kids, we will also study how to handle the
parents. Many times parents require more counseling
than you guys. I hope you understand this.
Is this correct, why, you know the reason.
So, you know what you have to do as a technologist,
we have to start understanding the origin.
And then from there we have to see what type
of DNA you carry. And how much I can refine
your DNAs to make you a perfect technologist
okay, so what we will do is, let me talk about
the course structure.
See, we will talk about this description of
the material first. So, description of soils.
Now, as I said, some time back, we are going
to talk about the origin of soils. Because
you must have realized, you know, I was trying
to link the offsprings with the parents, I
was talking about something related to genes
and DNA. And then I was talking about refinement
of DNAs also clear. So all these things are
linked with each other.
So, I will be talking about origin of soils.
So this is where the linkage between the parents
and the offsprings is going to be. I will
also be talking about the rock cycle. I am
sure you must have studied it in your engineering
geology course. Is it not. Now this is to
understand the material and its heritage,
linkage, parentage. How many adjectives I
have used. Is this part clear? So I am trying
to link all these adjectives, heritage, linkage,
parentage, and what type of kids the samples
with whom I am interacting are.
And what I can do with them. How best I can
utilize them. Is this correct, Now, having
done this, I will spend some time on this
because this is very important to understand
your heritage, your origin, how you got originated
clear and then you might have changed your
city and you have landed up in Bombay change
of place, so you are transported from some
place to another place you are deposited here
and so on.
And maybe after 10 years, you might buy lot
of things in Bombay city and you have established
over here. The same thing happens in soils
also clear. So, then we will be talking about
the basic relationships. You say we are engineers,
technologists. So, ultimately we want to dictate
terms with the material clear and that has
to be in mathematical form. So having understood
the material, what we will try to do is.
What are the basic mathematical relationships
with govern its overall properties, characteristics.
This is what we will try to do. okay, so this
is the basic relationships. Then we will be
talking about the characterization of soils.
You know, the best way to understand anybody
is do all sorts of examinations, test clear.
A good example is modern day medicine system.
You go to any hospital, doctor does not want
to see you, what he or she wants, ten test.
Go to pathology, get these tests done, report
comes on my screen, take appointment deposit
money, I will tell you what the disease is,
is this correct, same is our profession. We
have an idea about what the origin is, what
the description of the soil is, how it was
formed, where it got originated, from where
it came to certain place, what happened later
on, develop some mathematical relationships.
And then try to characterize it, so that we
can understand it better. So, when we talk
about the characterization of soils we will
be talking about index properties. This is
the best way to understand you know, it is
similar to the pathological report, the way
the doctors sitting in their cabin, diagnose
you as a patient sitting in my office and
depending upon my laboratory staff, whatever
properties and the parameters come, I can
create a hypothesis in my mind.
That look this is the material which is prevailing
or which was, you know, available in this
portion of the country or the world and what
I should be doing with it, are you getting
this point, are you getting a larger picture
out of this, yes Sidhanth. Yes, Sidhanth and
you told that whenever you hear any type of
soil, it creates a hypothesis in your mind
very good . That what could be this hypothesis,
hypothesis maybe about the properties of the
soil are.
What is the hypothesis of a captain of a playing
11 cricket 11, what is that, what is the hypothesis
having in his mind when he is on the field
to win the game, no, to strategize very good,
what type of strategies which at what time,
what decision should made be very specific
what type of decision field placement okay,
how to utilize the filters, how to utilize
the bowlers, yeah, how do utilize the batsman
strategy, strategy.
Now same thing I can do by characterizing
of soils. That means if I have the blood report
in my hand, if I have all the properties,
what I can do? I have a strategy in the mind
that look I should be using this material
for this purpose, you got it whether this
is going to be a good material for creating
a foundation or not, whether it is going to
be a good material for stopping the fluid
flow transmissivity.
There could be situation where I would like
to enhance the transmissivity, there could
be a situation where I would like to reduce
the transmissivity. So, the way I am speaking
what feeling do get I am the master of the
material and the master of the situation.
Are you getting this point, the material remains
same. But what I am going to do, I am going
to create a strategy in my mind that how I
should be utilizing this material.
So when he says permittivity and if I am a
let us say, petroleum geophysicist whose job
is to dig oil well and produce more and more
hydrocarbons for the country clear. Transmissivity
should be more, the more and more production
you should be doing are you getting the point.
But suppose if I am creating a dam, where
the whole idea is to stop simple water so
that the water remains in the dam for entire
year.
Otherwise what is going to happen. This year
it has rain, you are not sure about what is
going to happen next year. So that means the
same material, I should be able to create
a strategy to either allow permeation of the
fluid to take place or not. Now that art you
can learn, when you understand how to read
ECG, how to read characteristics of the soils,
and so on, which is mostly being done by the
laboratory staff which does not mean that
you should never learn it.
You should also learn how to characterize
the soils by your own self, then you have
more command on the things. Okay, so now,
what we will do is index properties yes. We
will talk about the soil structure. Now the
way I am sure this, my dear friend must have
used this word structure, structure has a
I do not know some one of you have used most
probably you Is it not? So the structure has
different connotations in soil mechanics and
geotechnical engineering, what type of structures
we are talking about.
Let us first talk about the structure of the
soil itself. Understood, and then we will
talk about the structures which are going
to be sitting on it or made with this or made
in this how many terms I have used. I know
I have twisted a lot of things. So, I was
talking about structures made by this material
made in this material made on this material.
All are contextual. So, slowly and slowly,
remember the material remains same.
But what I am doing I am creating different
situations. So, God willing this we will be
discussing in your next course, that is the
application of all these concepts which you
are going to study in this another 30-35 lectures.
So, more emphasis would be to understand what
the material is and then negotiation and mastering
the material will start in the next semester.
But here has the stage will be set by the
end of this course, that you should be able
to do net practice.
What is net practice, you understand what
is net practice, is this clear, very good.
So, now, what we will do is we will talk about
soil structure is something different than
what you might be understanding right now.
So, suppose if I asked you what is the difference
between your T shirt and his T shirt, structure
is different, texture is different clear.
So, mostly the guys who are into fabric technology
what do you call this as is of course, textile
engineering, but they normally talk about
the fabric of sorry structure of the fabric.
Here we will be talking about the structure
of soils, is this clear. No structure is resting
on this. No structure has been made by using
this material. No structure has been made
into it. I am just talking about the structure
of the soils. Incidentally, these 2 guys out
of ignorance are talking about sands and clays
and mud. Each of this word has a connotation.
When you go and speak in a scientific world
or in a international forum or national forum,
where the technical guys are sitting.
Now if you say mud, the connotation is this.
If you say clay connotation is this clear,
so you have to be careful. Anyway, you will
learn this. Then we will be talking about
soil classification. Because the classification
of soil is based upon whatever we have studied
by this time starting from its origin, the
way it was created, the way it was transported,
the way it was deposited, clear, forget about
the basic relationships, index properties,
which are very, very particular to and the
signature of the material alright.
Signature means, I do not know what how do
you define the word signature of a material
. The best way would be, this is what the
material itself is uniqueness. And then comes
the soil classification. So, once you tag
CE 323 S2 division, it is a classification,
it is understood that these guys know all
these things, whatever has been discussed
in today's class. Is this part clear or not.
That becomes a class.
And then people start saying he is in a class
apart. No, what of the meaning of this word,
you are representing a class which is totally
different than rest of the things. This is
what we will try to do, we will try to put
a material into a specific class so that I
did not have to talk about much of micro details.
I will simply say this is a class. Use it
like this strategy clear. So I will be using
this materials in the last the depth overs
clear.
These materials will be in the middle order,
and so on. So that strategy comes from here.
Now what we will do is we will go ahead with
the now comes the engineering properties.
So this was as far as the material properties
are concerned. Draw a line over here. So,
this is mostly on the material how are you
going to do engineering with this material
fine. So, engineering aspects would be we
will be talking about soil compaction.
Any good example we are compaction you might
have heard of rollers perfect cricket matches
mostly is it not, they take light rollers,
heavy rollers, id you have the question why,
we might get some answer from here. So, soil
compaction is an engineering property of the
material. Here we will be talking about you
know laboratory compaction techniques. And
field compaction.
Any other examples where you think compaction
becomes important, packing in a suitcase is
also good, yes, yes, yes. Okay you are compacting
the material there alright. Apart from that
do not pack your suitcase right now you have
come from home. Okay. Any other example where
you think compaction is critical, important,
you might have seen roads yes. So you are
aware of this alright.
Now, having done this, let us put it as a
class A of engineering properties alright,
so the first engineering property is compaction.
The second engineering property would be soil
water statics, the statics. The best way to
learn soil mechanics is follow the art of
making pitches, so cricketing pitches, cricketing
turfs, tennis turfs, hockey turfs, football
turfs you know why, all this is very practical
and highly applicable to preparation of a
turf, any type of turf clear, the turf material
might change the compaction level may change.
So sometimes captain say dry rolling, sometimes
they say sprinkle water and roll. So look
at this what I have done, I have related soil
compaction this soil water statics, okay,
so we will talk about this. Now from this
point onwards, we will also talk about effective
stress concept because when you are compacting
something truly speaking the compaction is
by applying certain weight, it could be static,
it could be dynamic, it could be impact.
Trains which are moving on the railway track
are beautiful examples of what type of compaction,
see the railways which are moving on the track
and that sound come cut cut cut cut cut is
it not what is that yeah vibration is induced,
we are talking about the compaction first,
rolling is taking place clear, the self weight
is there, impact is there, clear so 2 there
could be I can apply a huge load static condition.
Suppose train stops on the railway track and
then their load of the system is getting transmitted
on to the railway tracks. Through that sleepers,
which are resting on ballast, and ballast
is resting on the foundations. Clear, again
the mechanics of the material, how the loads
and the stresses are getting transferred from
a system on to another system and how it gets
dissipated up to the foundation level.
So, when you talked about the foundation,
I am sure you were talking about only the
foundations of the buildings. Now I have created
a situation where I have given an example
of foundations railway tracks, got it. So
foundations is a very general term. Is this
fine. So we will talk about the effective
stress concept. We will also be talking about
the capillarity phenomena which all of you
have done in your 10+2 physics.
Now, the time has come in to utilize the concepts
of 10+2 physics into the real-life engineering.
So we will develop few simple and basic models
will try to apply these concepts into a system
like soils when they get compacted clear and
there is some soil water statics which is
going on, because of which the pore-water
pressures may develop. I am sorry, I have
used the technical word today, I should not
have used. So I withdraw it, we will talk
about this later on. So because of this system,
the effect stresses are developing the system
and the root causes capillarity.
Now comes another engineering aspect. Is this
okay if I write like this, the another one
would be flow through soils, what we were
discussing flow through soils. I think this
is what you were talking about. And I think
I gave you some examples also. There is a
very significant phenomena we call it as the
permeability alright, so we will discuss about
this engineering property in detail.
There is something known as a quick sand condition.
There is an advisory during each monsoons,
why you should not be going close to the beaches,
seashores and the areas which are very susceptible
for quick sand condition. It gets drawn in
the sands very good, perfect. So that is the
condition which gets created in beneath the
buildings. And no wonder when you get up in
the morning and you read Times of India you
say one building has sunk now you know the
answer. clear.
So, as an engineer your job would be how to
stop this condition to occur in field. See
here when we talk about the flow through soils,
we will be talking about the permeability.
And then there are different types of tests
which have to be done. There are different
types of tests which have to be done, some
of them are laboratory. Incidentally there
is there are 2 types of tests normally either
laboratory tests or field test.
And we are supposed to do both to understand
how the material behaves in controlled environment
which is the laboratory and under natural
environment which is the field condition.
So, laboratory and field conditions alright,
those of you who are interested in joining
after your fourth year oil and gas companies.
Believe me, your fundamentals are absolutely
0. And most of the time I have been interviewing
few guys and fortunately, nobody knows me.
And what I have realized is that absolutely
no understanding of the basics of the subject,
but your aims are very high. You want to get
big salary packages without knowing the basics
of the subject. So all these oil and gas companies
they rely too much on and simulation. So nobody
is going to take a risk of making an oil well
you know, unless you have done the simulation,
we will be talking about the flownets.
Flownets are nothing but the regime of how
the seepage occurs through the compacted soil
mass or the soil mass itself alright. So this
is also an engineering property. Now, shifting
this concept, so let us say this would be
engineering 1. And engineering 2 would be
the stresses in the soil. I think I gave an
example of the moving train the stresses in
soil from surface load. Here we will talk
about different theories.
How to compute, what is this known as is state
of stress in the soils, those of you who would
become an expert in transportation engineering
they would require it a lot because of ignoring
this effect, you can realize the state of
our roads alright. So, how would you do the
best possible engineering to design the best
possible pavements. The answer comes from
here, what type of stresses are getting induced
on the surface because of a moving vehicle.
It could be aircraft, it could be railway,
it could be a road transport, bus whatever
clear. So, how this stresses are going to
generate in the system, what is the state
of stress in the soil at a given point, this
is what we are going to spend time on. We
will also be talking about the contact pressures.
Now this contact pressure is between the loading
area and the soil mass. Here comes the example
what you are citing.
So there is a foundation which is sitting
on a soil mass, what is the contact pressure
between the 2 original interface or at the
interface. So this is what actually we will
talk about contact pressure. The most important
thing we will be talking about is which is
stress induced, what is known as consolidation.
So consolidation characteristics of soils
and what is their applications. So, all of
you who are interested in infrastructure related
jobs should be very thorough with these concepts
of you know what type of loads come.
How do they get dissipated in the soils, how
the consolidation occurs. In short, consolidation
is a phenomena where the compression of the
soil mass takes place over a period of time
because of external loading, clear, we will
discuss this in details. And then we will
be talking about settlement analysis. So this
is the settlement analysis of soil mass, the
course content appears to be quite elaborate
or its reasonable.
Be attentive in the class because the best
way to learn, I can assure you though I am
going to give you a list of the books that
you should be following. It will be very difficult
on your part to refer to these books, but
you should refer to these books particularly.
It is not that I am selling my subject. Please
do not mistake me. It is a very important
subject and all, I mean everything rests only
on the ground or the soils alright.
So the 2 things which I wanted to convey to
you, I am going to give you a list of books.
But please discuss in the classroom, do not
hesitate if you are not following anything,
and make sure that if you are not following
anything, your next neighbor you know your
neighbor is also not following anything. So
there should not be any hesitance or maybe
resistance in your mind that you are not going
to open up.
It takes time to pick up the concepts. But
once you have picked up the concepts you become
you can discover your own shoats. Okay, so
list of books.
But whenever you get time, please get hold
of some of these books. You know, the first
book and the best book in the market would
be Craig. I am not writing the full form what
I will do is I will send you the list of this
on email. So those of you who are interested,
can either buy it or may be keep it with you
in case you go for masters or higher education
or you become a consultant tomorrow , you
will declare these books remember.
These books will haunt you throughout your
life as a civil engineer. It is a must to
read this books. The Another one is Holtz
and Kovacs, very high funda book. So if you
do not have time, do not bother about this.
At least you should know these few names.
The bible on the subject is by Lambe and Whitman.
Most of the titles are soil mechanically like
the first one is Craig soil mechanic. The
second one is an introduction to geotechnical
engineering.
The third one is soil mechanics. The fourth
one is Michell and Soga excellent book for
the guys who really want to adopt geotechnical
engineering as their profession, another good
book by Gopal Ranjan 
and A.S.R Rao, basic and applied soil mechanics,
there was a time when most of us used to read
the books which are written by the father
of soil mechanics, this is Carl Terzaghi.
If you are really interested, try to get hold
of this .
This book is by Terzaghi and Peck when you
do a course on foundation engineering, you
will come across this name of Peck, Hanson
and Thornburn. Fortunately, my master supervisor
was a student of Peck. This is the linkage,
heritage, or what do you call it parentage
it is very important, you know, another interesting
book you should study but not during your
B.Tech days, but when you pass out, you know.
It is an interesting book which is written
by Malcolm Bolton. This is a sort of an autobiography.
And this guy was a professor at Cambridge.
So, he has written about his experience a
guide to soil mechanics by M. D. Bolton, Malcolm
Bolton. There is another good book written
by B.M Das, this is principles of geotechnical
engineering. Try to get hold of these books.
Some of these books are available.
But my recommendation would be at least have
a copy of this because I will be following
this once in your life, read this book. And
if possible, read this book. This is okay.
And of course, this one you should keep when
you if you want to become a consultant. This
is a must for all undergraduates. I will be
following mostly this book whenever you get
tine in a leisurely mode, please read just,
follow this. And this again is a Bible.