 Having realized that these soils being the offsprings of the rocks more vulnerable to the environmental attack, more vulnerable to the human attack, human interventions, human abuses, fine all these words we will be using. This material becomes you know a big question mark, how it is going to behave under a given circumstances and we have talked about several circumstances. We talked about solar light, UV radiations, we talked about thermal influences. If you remember sometime back I said the nuclear waste which is getting processed is being dumped it comes in contact with materials and this waste is at elevated temperature at very high concentration, chemical concentration of chemical species. It could be also having the radionuclides in it, now the problem has become complex alright. So how soils are going to behave when they come in contact with this type of situation. So the conventional soil mechanics does not talk about the situations, I hope you will agree. Everything is within the you know normal room temperature conditions, STP standard temperature pressure conditions. So you say 27 degree centigrade, one atmospheric pressure everything is happening, very nice. But in nature nothing is happening of this sort, I hope you will agree, the ample examples where neither the temperature remains constant nor the pressures remain constant forget about the other activity which I have been talking about. So now the time has come to question what is this mechanics of the material which we have been studying. So to begin with because all of you have studied soil mechanics, the first question is what is soil and the second question is what is the mechanics part of this. So I am sure you must have come across this definition soils are nothing but the loose agglomeration of the minerals and organic materials extending from the ground surface down to the solid rock. Now it is a very funny material because the definition of the soil depends upon the profession, I am sure you must have realized this. If you talk to a agronomist, agriculturist for him the definition of soil is totally different, he does not bother about silty fraction, clay fractions and fractions, he simply says whether this soil is fertile or not. So for him the definitions are two, fertile, non-fertile, it so happens in fertile than you might be producing a produce which could be rice where the water permeability has to be extremely low, it has to be you know puddle, we call it mud and so on. You talk to a sculpturist, for him the definition of soil is totally different, the one which can be utilized for creating sculptures, pottery makers nothing should crack, his definition of the soil is the soil which would not crack when you are creating artifacts out of it, is this okay? So another thing is beauticians, you talk to beauticians, for them the soils are the ones you know you use your face packs and so on, these are all minerals which are being used, in most of the toiletry what do they do, they add these minerals. So the definition of the soil depends upon the profession in which you are, we are engineers, for us the definition of soil is totally different. So we started saying loose agglomeration of minerals and organic material, clear? So organic matter comes from the vegetation, it is a loose state of the material as compared to the rock which we have discussed and what is the domain in which it extends from top to bottom, so this is what I discussed, now as far as the mechanics is concerned what is mechanics in your opinion, so mechanics basically deals with the patterns of the response of the material, remember your bearing capacity test, plate load test, so you take a plate keep it on the ground surface, load it from the top and then what happens, slowly and slowly as you keep on loading the system, the slip surfaces develop and the chances are that the plate may get embedded into the ground, alright? So truly speaking the mechanics is nothing but first of all you are trying to understand how the material behaves and the second challenge would be how to quantify this, so then you have several theories, you use the concepts of physics, mathematics and then you put them together to create you know the mechanics which is the language of the engineers, how would I utilize this concept of how do these materials behave in environmental geomechanics, that is very interesting to follow. So I have created several situations which I have been discussing is it not, the ways coming in contact with the geomaterials, this could be soil, this could be rocks, when you come across a person whom you do not like what happens, emotions play a very important role and if emotions do not remain under control what happens, they may become psychosomatic also, blood pressure rising why because you do not like a person, the interaction started with the eyes, there is no physical in fact, clear, it is a visual interaction, the mind starts responding and the way look at the body is responding, your BP goes high, your palpitation changes, clear and if it goes on further what happens further, so it sometimes it may result in crying also, look at the way how body is behaving, now what similarity I am trying to create between the body human system and the one which is going to happen when the interaction starts, so I created one example of interaction between a innate material like soils and rocks when it comes in contact with environmental effects, so what porters do, what brick man does when they make bricks, as long as the bricks are green they just put them in the air for drying and after that they bake them and what happens after baking, they become very strong, so what has happened, this is how the system has behaved to a situation and what is that situation, elevated temperatures, are you realizing this, so the moment you put this system in elevated temperature the system became 35 MPa strength, 45 MPa strength, do autoclaving, temperature along with steam pressure, you can go very high in strength, that means now this is a combination of the pressure and temperature both, so are you realizing how situations create a sort of a response out of the material, this is quite clear, this is what actually we are more interested in understanding and then once we have understood how the material behaves, how the material responds to a certain situation, I would like to quantify this because tomorrow I am going to use this quantified version of the material response and that is nothing but the environmental geomechanics, the tools of the mechanics will remain same, but what we are trying to see is the response of the material to a given situation, circumstances, I created circumstances, look at another circumstance, you like somebody too much and the moment you see him or her what happens, nothing of this is going to happen, you agree, so what has happened, the body was same, the material is same, it is responding to different circumstances, so to me the circumstances are much more important as compared to the material, material becomes immaterial, you like this idea, the material becomes immaterial and what I have to do, I have to just control the situation in which the system is going to be and then as a technologist what I am supposed to do, I am just supposed to deal with the material to tell it the way it has to behave when I order it, that is mastering the material, this is the art which we are going to discuss, is this fine? Are you enjoying the philosophy, Mitra, Mitra is correct? Yes, so what is your reaction to this all discussion which you are having in this class? We get to see from a new perspective like how different materials react, very nice, so you use the right word in the beginning itself, you said that we have to look at the material with a different perspective, excellent, now this is the bottom line, so the way I have been looking at the material soils and rocks is no more valid because we have ignored lot of aspects associated with this and this is what actually we are going to study much more in details. In other words, we are going to look at the material in more totality, fine, yes Reshmi what you like to add? We have never come across a case where we give importance to the situation, we have always considered all the problems at a certain temperature, the situations will be we see the load, we always think about the load alone. Correct and load also is the mechanical load by the way, we will talk about different types of stresses which a system can sustain. So, I was trying to tell you a situation here where nothing is being loaded physically, clear, it is all psychological pressure which are developing inside your body and system and the way your system is behaving, reacting, I think this part is clear, yes, you like to add something. Before you compared the soil with our human nature, so the person remains the same and the situation differed, but my question is like though the person remains the same is it possible for him to see the means what to say like it is not mandatory that he has to see a person he likes the most. So, for soil environment changes, so how we are going to means it is not possible for us to make a correct decision on the environment, no, we are considering the situations we are using so many softwares and then failures occurs, so the environment changes. No or you might have ignored all those factors which are causing the failure to occur, so this is your short sightedness that your theories do not include the influence of the factors which matter more. So, maybe on the scale of 0 to 10, our knowledge is still at 1.5 or 2 at most and other 8 scales have not been fathomed by human beings yet. This could be another way of looking at the things that I know only this much right now, I have mastered only one compartment, stress and strains, the mechanics does not go beyond that and that too caused because of the mechanical loading. However, there are a lot of other things which you have discussed which have not come into the picture yet, maybe this is the answer to your question. Another way of looking at your question would be I can manipulate with the circumstance in which the material is going to be exposed to or might be sitting, is this okay? That is a technology, I can always play with these situations, I can amplify them, is this alright or I can reduce them. Yes, you can manipulate. So, I can do manipulation there also, so this is also one of the manipulation and then see what is the influence. You can conclude from that manipulation. Yeah, so I can master both the situation either I can master the material or I can master the situation. Whatever you do ultimately you are trying to create a near perfected solution, think it like this. So, either the material becomes so strong that is not going to be vulnerable to any of the circumstances, very good. That might be a situation. So, this is the logic which I gave, you take the clay, mix it with water, shape it in a brick form, dip it in water, it dissolves. Do the same process, green brick you bake and keep it in water, nothing happens. What you have done? You have altered the material. Now, this is the feeling which you have to inculcate in your mind that rather than being submissive with the materials and the situations, now what we are going to do? We are going to be the masters of both. Yes. By studying both? Yes. And then deriving a unique solution that I could manipulate the material this much and I could manipulate the situation this much and ultimately how best the most optimal solution can be obtained. That is a art. That is the technology. Clear? So, I am sure now you must be getting an idea about what we are poise to do. Is this okay? So, we are going to play with both the situations. Yes. As I said in the beginning of the class, this is more of a philosophy. So, what I am doing? I am just creating philosophies. We agree. Both the philosophy of the material and the situations. Yes, please. What you have to add? So, I felt we have to go so far on this topic like we never considered the environmental effect on. Doesn't matter, whatever has not happened, don't bother about that. Yeah. Is this okay? Sir, you gave me that example of brick emulsing in the water. Yes. So, maybe the condition of that water can change, you know. Oh, then now you are complicating it too much. So, this could be sea water, this could be acidulated water, this could be basic water, this could be water having a lot of bacterial activity in it. A lot of pathogenic activity in it. Sludge, which is coming out of the sewage plants. Nice. The sky is the limit of your imagination. So, the more and more you imagine, you achieve near perfection. And I am very sure now you can realize that when you did hydrometer analysis, you simply dipped the particles in water, you did not bother about any of these things. And of course, as you said the integrity of the material itself. Who knows that the soil was so organic that it will get completely eaten up by the chemicals which you added to do hydrometer analysis. Is this okay? How many situations I am creating one by one? Imagine. Just realize. Okay. So, shall we proceed further? We need to look at the all possible infinite situations and we can modify the material. We have more control on material rather than the situations. So, we can make. Yeah, simple example is when you are working, let us say the same concrete which you are using for non-earthquake zones and highly active earthquake zones. What do you do? Your design practices change. So, what you have done? You are taking into account some other factors which are going to create a sort of instability in the system. So, you are extra cautious. Is this fine? That is it. So, the material could remain same. The situation may vary. The situation could remain same. The material may vary. I may have to see on both the ends and then derive a solution which is going to be more practical, optimistic, optimal. Yes, you want to say something? Yes, please carry on. This course is all about realization, nothing more than that. I hope you can realize this. Is this correct or not? This statement. The more and more you close your eyes but not shut down your mind and ask questions to yourself what I am doing and why the answers come that yes, this is what should be done. Yes. I was just saying that the control over material is more than the own situation. So, we can make our material more and more. You have seen microwave ovens? Yes. Ovens for that matter. All right. There is a wide range of temperatures at which you can bake the cake. It depends upon how much in a RE you are. That is it. So, I can create a situation in which I can create a response of the material which is controlled. So, when you are a technologist, look this is the difference between engineering and technology. I hope you are now realizing the question which I asked normally. What is the difference between engineering and technology? You have mastered both what engineering was doing. Try to question. Somebody said last 40 years this has been done. You keep on doing this. I said no, I do not want to do this. I want to understand what has been done, why, what are the failures and how to rectify them and how to get a better answer by using a better technique. Is this okay? So, we will be talking more and more about all these things. Yes. Sir, I can relate this to Chernobyl nuclear disaster. So, where people say like the radiation effect is like trillion bullets to a human being. So, before that we cannot, like we will not foresee the conditions of the soil present over the Chernobyl. So, how to quantify that that much amount of radiation? Like we cannot simulate the conditions in the laboratory. So, what is the solution for that? That is right. So, we will get these answers. This is what the modeling techniques are. Sir, for example, if you see gas hydrates, we are simulating the pressure. You are not connected to gas hydrates. For example. Yeah, yeah. But for the like soil at Chernobyl, we cannot like predict the radiation. So, it is very huge that it is equal to like trillion of bullets to human being. But what about the soil? So, how to like design that soil or buildings? Correct. Yeah. So, all these things we have to discuss. We have to question and if there are no solutions given in the books, we have to create them. Then only people will remember us. Is this correct? If I am just reading books without questioning and without finding out what does not exist, makes no sense. World has to go on. Knowledge has to explode further. It has to be created. Yes. Fine. All right. Okay. So, let us go ahead. I think we have created enough situations and I am seeing how the material is responding. This is also very important. What are the patterns we can observe? Clear? So, a simple example is when landslide is occurring. You know, mechanistic approach is the small, small boulders or small chunk of the soil getting detached from the parent body and sliding over a slip surface. Okay. What is the next statement? How many things you have ignored? How many processes related to physics and mechanics you have ignored? Whenever a slippage is taking place, whenever a cracking is occurring, whenever a mass is moving with respect to a surface, a lot of friction is getting generated and that friction might be elevating the temperature. There is a detachment. There is a sound. All these things we have ignored. You agree? So, when the new mechanistic models for the landslides would be where you talk about all these things together in tandem. In tandem means when all these processes get attached to each other. So, material getting detached from the system, lot of sound comes out, lot of dust is created, lot of slippage is taking place, lot of friction gets induced, lot of heat is going to get generated, what this heat is going to do to the material, how the moisture is changing, how the shear strength parameters are changing and so on. And you are talking about the material particle becoming you know either bigger or smaller because of its interaction with the water, air, microbes and what not. So, we would like to see what are these patterns. So, if I say that if I apply a sudden force on the block and block is moving on a rough surface, how much heat gets generated is the pattern.