 And about myself I am DN Singh, 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 Aditya. Aditya, yes, there will be so many Aditya's in the class. So Aditya Upadhyaya. Aditya Upadhyaya, yes. My question is, what you did not learn over here, which forces you to study geotechnical engineering one, which is also known as soil mechanics. Soil properties. Okay, so let us complete this list first and then this is Vis-a-Vis soil mechanics, alright, which is the modern name is Geotechnical Engineering One, yeah, you were saying something Aditya. So, in these courses we never learnt about the soil properties, on what the structures are built or how the fluid is going to get affected by the soil building. 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. We never learnt about that. So, you have already read everything. What are your expectations? Sir, I am Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. Shashank. My name is Yash. Sorry. Yash. Yash. Yes. Okay. So, the specifications are pretty much same. Sorry. Pretty much same. Speak clearly. How soil behaves when it is exposed to water. How soil behaves. How water transmits to it. How water transmits. Transmits through it, alright. So, the property like how much strength it can be. How much strength? Very good. And nice. My name is Rohit Chaudhary. Yes. I think that for any structure, this course will help us to determine the type of foundation. We are going to. Who gave you this idea of foundations and all? Means depending upon the soil, we will choose the type of foundation. We are. You are much, much ahead of your time. You understand. See right now you have to understand the soils. Good. But that is a good application of what you are 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 ABC of a new material. So, that is why what I have done is I have listed materials as number one. You see, you are talking about fluid mechanics, structural mechanics, solid mechanics, engine mechanics. Truly speaking, this should have been an inverted pyramid. Sir, currently we are doing structural mechanics too. Forget about what you are doing. What exists? What you should be aware of? Think about it. Next. Your name, at least tell your name. I am Shantanu Chhaapariya. 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. Biomolecular mechanics. Is this 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 thing which comes to your mind? Nanomaterials. Nanomechanics. You are from IIT Bombay. Is it not? IIT Bombay is famous for what? Nanocenter. Clear? Biomechanics of everything. Now, let me ask you a question. What is so common between nano material and soils? Any guess? Mahima. Yes, please. Both are small particles. Correct. How small they are? What is meant by nano? Any example of soil which you think is a nano particle? Next. Much lower in the particle size range as compared to sands. My name is Anikir. Anikir. Yes. Okay. Very good. Not knowing is not crime. Myself Shubham Surya. Maybe. Say it again. Myself Shubham Surya. Shubham. Yes. Okay. Maybe mud is a type of. Very good. So mud is a layman's language. Can you define your answer? What is mud? You are quite close. Very good. Excellent. So, clays are the nano materials. What is that I am trying to draw a similarity between? Yeah, hi. My name is Akshath. Akshath. Yes, sir. Yes, Akshath. What is the similarity I am trying to draw between the nano materials which you normally talk about in material sciences, electronics and now my question is why I am discussing this in the class which is meant for civil engineers. Maybe the properties of nano materials can be the same. Clays themselves are a nano material. Okay. So, by studying the properties of clay we can have some. Civil engineers were the first to talk about the nano materials in the history of civilization and much later came the application in the field of electronics and other fields. This is the message 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 different types of soil and its properties. No, no, no. If you are 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 one. Anything which we have missed out in this series. He was talking about the material. Somebody was talking about structure testing on this. Somebody was talking about the transmissivity fluid passing through this, alright. Then somebody was talking about the strength and so on. Then this guy started talking about the foundations and then I stopped them over there. I said, no, this is the 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 BTEC and other institutions give you BE is a big question. And what should be your role as a BTEC degree holder? I am sure you are not questioned 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 Manan, interaction, whatever interaction. I have to understand the material first, clear. And then only I will jump on to what type of foundation I have to provide, what type of structure 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 you have to 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 Jan. Say it again, Sankpal. Arpan. Arpan, yes. So, what is the meaning of the word communication with the material? The properties. Very good. So, communication means the way you want to talk to any of your friends. You do not know the 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 one 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 range how many grams, kilograms and tons of soil is getting washed out because of the range from the gymkhana. Now, this is a good example of transmissivity which you are talking about. Now, if this happens inside a dam, 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 say 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 4th, 5th, 6th 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 it should be behaving and then a stage came when you started negotiating with it. That look, you have to be stable here for 30 years, 50 years, 60 years. I am 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 mechanics when I studied, I studied this maybe I do not know how many years back. I am 86 pass out. So, 82, 83, 84. 1984, I must have studied soil mechanics. Those days, the subject was more of bookish. But now things have changed. Everything has a practical connotation. Everything has a practical meaning, applications. So, whatever you are studying in the classroom, unless you have understood an application of it, you should stop your instructor. And ask the question that I am not very clear about what is the implication of what you 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 soils also we will study. That means you 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 we 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 sometime 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 this in your engineering geology course. Is it not? Now, this is to understand the material and its heritage, linkage, parentage. How many objectives I have used? Is this part clear? So, I am trying to link all these objectives heritage, linkage, parentage and what type is 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 got transported from some place to another place, you got deposited here and so on and maybe after 10 years, you might buy lot of things in Bombay city and you may establish over here. The same thing happens in soils also. Clear? So, then we will be talking about the basic relationships. You see, 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 which 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, tests, 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, 10 tests, go to pathology, get these tests done, what 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, 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 stuff, 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? It is Siddhanth. Yes, Siddhanth. 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 may be about the properties of the soil or. What is the, what is the hypothesis of a captain of a, of a playing 11, cricket 11? What is the, 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 fielders? Fielders. How to utilize the bowlers? Yeah. How to utilize the batsman? Hmm. Strategy. Strategy. Now, same thing I can do by characterization 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 a 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 you 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 permissivity and if I am a, let us say petroleum geophysist whose job is to dig oil wells 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 a point? But suppose if I am creating a dam, where the whole idea is to stop seepage of water so that the water remains in the dam for entire year, otherwise what is going to happen? Since here it has rained, 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. This 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, one of you have used most probably you, is it not? So structure has different connotations in soil mechanics and geotechnical engineering. What type of structures you 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 and I have to state 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 we 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 yes, 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 ask you what is the difference between your t-shirt and his t-shirt, the structure is different, texture is different, clear. So mostly the guys who are into fabric technology, what do you call this, this is a course textile engineering. So 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 two guys out of ignorance were talking about sands and clays and mud. Each of this world 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 the 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 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 CE323 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 is 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 need not to talk about much of micro details, I will simply say this is a class, use it like this, the strategy, clear. So I will be using this material in the last death 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. Taking good example, we have compaction, you might have heard of rollers, perfect, cricket matches mostly, is it not, they take light rollers, heavy rollers, did you have a 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 example where you think compaction becomes important, packing in the, 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 first engineering property is compaction. The second engineering property would be soil water statics, statics. The best way to learn soil mechanics is follow the art of making pitches, 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 captains say dry rolling, sometimes they say sprinkle water and roll, so look at this what I have done, I have related soil compaction with 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, the 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 the entire load of the system is getting transmitted on to the railway tracks through that sleepers which are resting on Velast and Velast 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 you an example of foundation of the railway tracks, got it, so foundation is a very general term, is this fine, so we will talk about the effectist stress concept, we will also be talking about the capillarity phenomena which all of you have done in your 10 plus 2 physics, now the time has come when to utilize the concepts of 10 plus 2 physics into the real life engineering, so we will develop few simple and basic models, we 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 will draw it, we will talk about this later on, so because of this system, the effective stresses are developing in the system and the root causes capillarity. Now comes another engineering aspect, this is 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, so it is a very significant phenomena, we call it as a 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 drowned 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 two types of tests normally, either laboratory test or field test and we are supposed to do both to understand how the material behaves in controlled environment which is a 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 you 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 the 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 flow nets, flow nets are nothing but the regime of how the see page 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 you an example of the moving train 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 or 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 these 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 two or between the 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 is 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 which 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 two 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 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 charts 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 are interested, can either buy it or maybe keep it with you, in case you go for masters or has education or you become a consultant tomorrow, you will require these books, remember, these books will haunt you throughout your life as a civil engineer, it is a must to read these books, the another one is Holtz and Kovacs, very high Fonda 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 Lamb and Whitman, most of the titles are Soil Mechanics, like the first one is Craig's Soil Mechanics, the second one is an introduction to Geotechnical Engineering, the third one is Soil Mechanics, the fourth one is Michel and Soga, excellent book, for the guys who really want to adopt Geotechnical Engineering as their profession, there is another good book by Gopal Ranjan and ASR Rao, basics 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, that is Karl Terzaghi, if you are really interested try to get hold of this, this is book by Terzaghi and Peck, when you do a course on Foundation Engineering, you will come across this name of Peck Hansen 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 BTECs days, see once you pass out know, this is an interesting book which is written by Malcolm Bolton, this is a sort of a autobiography and the 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 then if you want to become a consultant, this is a must for all undergraduates, I will be following mostly this book, whenever you get time in a leisurely mode please read this, follow this and this again is a autobiography.