 The first category is of marine deposits, very soft soils, very high moisture content, substantial portion of this type of soils would be organic matter. Now when the soils are soft and when they have high moisture content by virtue of these two things they will become very very compressible alright. Now when they become compressible what will happen, it is a boon or it is a bin. So marine deposits by virtue of their nature that they are close to the marine systems have very soft sensitive soils. Let me put a word sensitive here, when we say human beings are very sensitive, suppose if I say you are very sensitive what is the meaning of this? You get influenced by everything very quickly is it not, somebody say is not good, now you will be down for at least 6 hours, clear? Like that only these soils are very intelligent materials, they are very soft but very sensitive also, the moment you touch them they get disturbed alright, very difficult to take out the sample from the ground to bring them to the laboratory and to test them and to get the parameters which can be utilized for design purpose. So these are very soft sensitive soils, high moisture content why because they are in the water body all the time, organic matter is present, it is a bane for geotechnical engineers but boon for what, which industry, I am yet to see any agriculture form sitting on the marine clays, only oil forms can be there, hydrocarbons, so organic matter which becomes a bane for me is a boon for the guys who are into petroleum industry, Bombay High, there is only one Bombay High, have you heard about anything else, except for KG basin now, in Assam you have some oil fields, in western part of the country now you are talking about Ashura Reha and all these Navaratnas which have come out very recently in the deserts. So wherever you have organic matter, by the way calcium carbonate present in desert soils could also be organic in nature, clear? It could be inorganic also, it could be organic also, so this organic matter plays both ways, these deposits are known for good oil reservoirs, these are the petroleum reserves but as far as laying the foundations, construction of infrastructure is concerned, creation of buildings is concerned, very big problem, these are highly compressible just like a sponge. Another category is let us talk about the black cotton soils which somebody was discussing but believe me, you are lucky that you are studying geomechanics in the coastal region, look setting at the marine deposits, the saying is those who start their profession with marine deposits flourish much more, I hope you can understand why, because the challenges and the ways to learn the material and perfect it are much more as compared to any other part of the country. So the guys who are sitting in the northern region or hardcore southern peninsula unfortunate, they cannot practice this even much, you know, when I say practicing I hope you understand the meaning of the word practicing, is this part clear? What is practicing of a subject? What do lawyers do? They practice law, you agree? So this is the subject which is to be practiced, is this part clear? So black cotton soil is by virtue of the minerals which are present in it is a expansive soil, mind the spelling of the word, it is not expensive and most of the interviews where I said most of our graduates they say it is expensive soil, it is not expensive soil, all right, it is a expensive soil. The meaning of the word expensive is somebody is from Vidharb, who is from Vidharb? You, not really, but Indore, not Indore say, parts of Karnataka, Nagpur, yeah but these are the deposits where you have black cotton soil, Nasik is a beautiful example, all right. So these are the places where you will have mostly black cotton soil where you see the cash crops being grown. So these soil deposits are very good as far as cash crops are concerned, what are the cash crops? Cotton, number 2, there you are right, Haldi, oh I do not know, okay Haldi, third one, cash crop where main cash crop, sugar cane, big, big sugar industries are there in the whole Maharashtra region, all right. So because of the property of the black cotton soil it is, retains lot of moisture, not because of being organic and fibrous in nature, who was talking about fiber, you were talking about fiber, not being fibrous in nature, but by virtue of its minerals and the minerals which are present in this material are known as Mont Morillo Knight, clear. This is a cousin brother of Bentonite, another cousin brother of these minerals is Smectite, where do you use Smectite? In which industry? Sports, clear, so if you want to make pitches, so you have to have Smectite much more in proportion, it becomes a good recipe. So black cotton soil will have mostly Montmorillonite which is a type of a Bentonite, but it is quite rich as far as the agricultural properties are concerned why, the soils particles are very active chemically, so somebody was talking about in the very first lecture, sorption capacity of the particles is too much, clear. So the moment you add fertilizer, not even a fraction of fertilizer will go unutilized. Each particle of the fertilizer or each drop of the fertilizer in the liquid form will adhere on the particles because of their mineralogy, clear. And this also is a curse, bane, why? By virtue of all these things they attract moisture a lot. So the moment they come in contact with free water, if it is raining heavily and water gets logged, this mineral is water thirsty, hungry. What it does? It can take as much as moisture as possible, clear. So that is the problem and when the dry spell comes, dry season comes, this moisture gets lost. So it looks like a spring action, it swells shrinks, swells shrinks. So as far as the buildings are concerned is say not a welcome material. In earlier days the thumb rule was get rid of this material, excavate and replace the soil with better soil. Nowadays the problem is the constructions have become so big, huge. How would you dig it? Where you will place it? How will you bring soils from other place? How will you compact and so on? Lot of challenges are there. Now as far as the formation is concerned these are formed mostly from basalt and trap. Trap is type of a rock and that is why we call it as the decant trap, decant peninsula in India and this is mostly basaltic in nature, all right. So the type of rock which we have in Bombay region is very dense, very hard basaltic material, it is okay. So that is why it is very difficult to make infrastructure here, you know, excavation is very difficult. So this process is known as swelling and shrinkage. This also hints at the property that this soil is very intelligent, it can sense the atmosphere very soon, is it not? So the moment the atmosphere conditions change it starts behaving. Incidentally in case you get a chance to work in pharmaceutical industry most of the geotechnical engineers govern pharmaceutical industry by the way, I do not know whether you are aware or not. There was a time when I did a lot of consulting for Sandos and this is a very interesting process. Later on I think I told you about my association with Reliance Life Sciences also where we were talking about, you know, controlled porous media in the form of a controlled drug delivery system. So I can play with the minerals, I can make them so porous like rasogullas, all right. So those who have diabetes, what do they do? They squeeze out all the sugar syrup, correct and they just eat the porous part. People like us who are fat, they have consumed a lot of sugar and the bellies are out, clear? So this is the difference. So I can create a porous media where I can keep anything inside. I can keep a fertilizer, I can keep let us say chemicals, I can keep bacteria, whatever. So this is how you can play with the minerals. So you can fill them with something, you can squeeze out, you can allow them to shrink and so on and you can use them. Another category is anything else which I have thought of telling about the black cotton soil? No. So these are the good crop yielding soils, most of the farmers in Nasik and Satara and all these areas, you know, they grow a lot of sugarcane, then cotton, cashew nuts, three are cash crops. Fourth is now pomegranate, you were talking about healthy, I am not sure and what else somebody said? No, pomegranate is a big business in Maharashtra. Alright, the another one is laterite. How many of you are from Kerala here? So maybe the northern part and the middle portion of the Kerala bordering with Karnataka, I think you would have later write. Incidentally, when this Konkan railway was being done, 1995-96, the big challenge was how to cut these type of lateritic rocks and that was my first or second project. I was associated with the Konkan railways, you know, very hard rocks, but perforated, vesicules they would be having and that is because of the leaching. So anybody is from here from Mangalore? Wow, which part of Mangalore you are from? Near airport area or maybe towards the refinery? What is the name of the place? Kodikal. So somewhere close to NIT Surupkal? Yeah, so that is mostly later, lateritic belt. Alright, red color soil, you will be having impregnation of yellow and white inclusions. These are magnesium oxide, iron oxide and so on. The big problem is like human body, all these minerals keep on leaching out. In local language, they call them as shady soils. Have you heard about this? SHEDI shady soils. So a lot of people who have done research on this in this. So all these salts keep on leaching out because of excess rains and the system becomes vulnerable, clear? So these are the by decomposition of the rocks. It is an interesting chemical process which goes on by this. What happens is that bases which are present in the system, all sorts of bases hydroxides and silica. So this is getting removed and these are mostly oxides of iron and aluminum. In layman's language, we call them as red soil. In part of northeast also you will be getting the lateritic material. So these are the lateritic formations. Then comes the alluvium or alluvial soils. A typical alluvium is the one which is river broad sediments getting deposited over somewhere. Now this is what is known as alluvium, all right? A deposit of sand, mud, etc. formed by flowing water. So these are the layers of sand, cells, clays and this is a typical alluvium. These type of soils are who was from Varakpur, yes. These are prone to liquefaction, is this okay? Can you read this? So if earthquake comes, it strikes this strata, the soil mass start behaving like liquid, L, I, Q, U, E liquefaction. It just behaves like a liquid and we will study the state of the material. What type of state of this material is? How it gets induced because of the earthquake triggering? So the more and more motions which occur in the ground, all right, in the form of the shear waves. The liquefaction might occur. Fine, silty, sandy material is very prone to liquefaction. But I am sure you must be aware that a lot of money is now invested in the eastern part of Bihar. A lot of big, big factories are coming over there now, particularly DLW spending a lot of money, Siemens is doing a lot of work there, a lot of land reclamation is being done there and so on. This is a villain. If you can take care of this, you can do very good infrastructure. We will discuss about what liquefaction takes place. Now liquefaction is loss of strength of the soil mass due to earthquake. Earthquake is a natural phenomena. It could be manmade also. Yes or no? How? Iduki Dam is a good example of man-made tremors. Is it not? Terry is a beautiful example of man-made tremors. I might be laying a foundation of a moving let us say vehicle or a forging unit where the hammer gets dropped from a height. Under all those circumstances, there is an impact and impact is causing the loss of strength of the soil because of any vibration, movement, shear waves travelling through the system. Is this okay? Another category is desert soil. We have discussed a lot about it and I hope you understand the issues. Very difficult to stabilize these type of soils. Either these are Aeolin or Lewis which we have discussed today. I am sure those of you are from Rajasthan area must have realized that after independence, several tens of years it took to create a railway line over there. We agree with this. After Jodhpur, if you go towards Bikaner and all, no king was such a big fool to create artificial lakes. You know this, they were good engineers, good technologists. They have just utilized the geomorphological features of a place to convert it into a beautiful city and they were sustainable. Remember, we are dying for water. Bangalore has no water. Bombay city might not have any water who knows but these are the places where perennially there is no issue of water shortage. I hope you agree with this. You will never hear that in Udaipur water shortage, water scarcity. It is a miracle but not miracle. It is a scientific thought which was executed very nicely. So we have discussed this. Now I was talking about the infrastructure over there. The biggest problem is as I gave an example about the Indo-Pac border. You cannot create even railway tracks. What happens? The soil gets eroded. Is it not because of the wind? So desert soil is the biggest problem is how to stabilize them. Indian Army is doing a lot of good work there. Incidentally, if deserts are not there, where we would have tested our nuclear weapons? Imagine. So this is a boon. You agree? Where Pokhran was done? Very close to Jaisalmer, 30, 40 km away from Jaisalmer. So if you are going towards Jaisalmer, you will be passing by the area which is cordoned off completely by Indian Army. They do not let you go over there. So if you get a chance to work with atomic energy, AERB or BARC or like these type of organizations, you will realize that how this detonation of the weapons is done in sands and why. So you might get an answer to this question as the subject grows slowly and slowly. There must be some mechanisms. So I was talking about the shocks earthquake, then I was talking about the shear waves, then I was talking about how the migration of the shear waves occurs. And then if I have to test the weapons which are nuclear, these are the right places or the sea. Where would you like to do out of the two places? Testing of nuclear weapons, if not a given country, all right? Then comes the boulders. I think we discussed about this when we were talking about colluvium deposits, if you remember, all right? So on the steep slopes, many times the boulders, clay matrix, it falls down, it gets deposited and then it becomes very difficult to create infrastructure over there. These are the typical deposits of the country. Mostly the boulders are because of the rivers which are flowing through hilly terrains. Try to come out with the challenges associated with these deposits as far as engineering and infrastructure development is concerned. Though I have been telling you all sorts of problems, but it is a good idea to go through this in a literature form and read this. And in case you have a feeling that you want to give back to the society from where you have come after a few years, this is going to be a very good homework. So this homework is not time bound. This is for your entire life. Know your region properly. Try to solve the problems of the region and for that you have to study all this. So how to do engineering? How to do technology demonstration in most of these deposits which are so difficult to manage where people are unable to give a solution, all right? This is what you should learn. So let me take you through the some of the most challenging tasks which geotechnical engineers are imposed upon in their career and people describe them as problematic soils. And let me tell you one thing that this is the old concept. So when I was a student, you know, this is how we were introduced the topic, problematic soil. But after due course of time, I realized that there is nothing known as problematic soils. These are challenging situations. And if you are not having challenging situations, the profession would not have been so prospering, you understand? So this is where I write that because of the problematic soils, our profession flourishes. I do not know whether you guys know or not. I am the consultant to Navi Mumbai International Airport. The whole project was my brainchild. And I convinced the government that this is how it should be done in the least time and with the least money. Ideas just come when you teach in the classroom and somebody asks you a question. Reclamation is one of the examples of how this Navi Mumbai International Airport has been done. So before I stepped on to the ground, the site was problematic because it was a part of the creek. And active sea is a Panvel Creek. I do not know whether you are aware or not. Creek is the one place where most of time water remains stagnant. It might be flowing also. So Panvel Creek, if you see on the Google map, it is adjacent to that is the 1300 acres which is 3 times the IIT Bombay campus. And this is what your new airport is going to be. Just for instance, I am giving you this example. So there was a time when this problem used to be a problematic situation. But now if you go there and if you go see it on the Google Earth, 50% job is done by applying some technology. So what I am trying to convey to you is unless the problematic soils and challenging situations are not there, the profession cannot flourish. So when I was making these slides today, I got a phone call that somebody wants to meet me at 6 o'clock. You know why? I will show you. This profession is becoming mostly you know a sort of a legal, techno legal, social profession. So this is where I write that it creates a lot of professions. Let me describe few situations. I am sure you must be coming across these types of problems. This is a common problem. Why to go to Himalaya? Even in Bombay itself, this is a big problem. Most of the slums are located on hillocks. And every race, you read in the newspaper that the buildings have collapsed. Is it not? So look at this. The entire slope has got washed out. Now this is a typical boulder. You know, we were not been talking about. The whole soil profile is weathered soil. It was a beautiful basalt, decant trap. In the due course of time, over maybe millions of years, the top surface of this rock got weathered and these are the remains on which people have started making their buildings. So because of the rains, what happens? The whole slope has got washed out and look at the foundation. Foundation is hanging now. The clever Janta Bombay, what they will do? They will create a pillar over here and they will support the building again. The beautiful example, you go whenever you are going to these places, I mean not to name such areas where you will find such type of solution which exists indigenous solution and people are living comfortably, I cannot of course. Pipelines have got exposed. It is a typical bouldery, clay, silty deposit. Appears to be a weathered material. You were talking about weathered material, somebody from this section. I think you were talking about weathered material or before the break. Anyway, this is the weathering of the material. Mostly caused because of water ingress and water causing pressures in the material, material gets fragmented. This is also a type of a slope failure. So when you drive through Ratnagiri area, you know, there are so many slopes, Khandala Ghat, Karjath, all these areas where you will find a lot of landslide occurring mudflots, we call them. So the entire mud has come down. There is a typical class of problem with geotechnical engineers come across. I mean you have to open up your highways. I do not know how many of you read newspapers and there is a big debate going on in the parliament also now. A famous highway which is in JNK and which they want to construct and about one and a half month, two months back there were 5000 vehicles which got stranded over there because of landslides. It is a rather interesting problem, you know. Pipelines are the veins of the country, arteries and veins of the country. Why? Like your body, you know veins and arteries, what do they do? They flow blood. These are the pipelines which are flowing as a water. You must have seen water comes in Bombay city from Nasik. Most of the time when you drive through the Nasik highway, we are not water sufficient by the way. We get water from different dams in Nasik. They were done by Britishers or crude oil, again the economy. Now if these pipelines are located in the regions like this where the ground is not stable, what is going to happen? It will result in losses, alright. So rather than conveying the fluid, there is a lot of spillage. The pipelines get distorted, they might get broken and so on. The cause over here is if you look at this, the foundation has got completely washed out. So next time when you are travelling from Thana towards Nasik, remain awake and keep on looking at on the left hand side of the entire pipeline system and see what type of foundation they have provided. By sabotage, if somebody blasts off the foundations, it is a right now NSG topic to work on. National Security Council, you know how to stop sabotage against the pipelines which are carrying precious oil, hydrocarbon or water even. Water is also very precious by the way. So look at this soil erosion has occurred. Subsequently the road has collapsed. These pipes have also yielded and just because of the poor drainage, I am sure this you must be seeing every day in your hostels also or maybe buildings where you find cracks which are occurring on the walls. And this is again because of, remember we have talked about the climatic conditions and black cotton soil too much expensive material. It attracts water, repels water and so on. Separation of the wall. There are several situations where the doors and the partitions which are done, they got separated from the floors or the walls. And this again because of the differential settlement. So we will be discussing about the settlement in details. It is a classic example of 1945-1947 when the entire road has become you know almost like a snakey we call it topsy-turvy. Why? It is all because of settlements. Most of the roads in the city are like this. It is so what do you call it, derogatory to live in a society where the roads even cannot be made properly. Look at this. Another interesting case where the, this is the beam which is getting detached from the wall and the crack is developing. These cracks would be, they could be traversing top to bottom in a zigzag manner. They could be vertical splits. They could be even horizontal also depending upon the situation. One of the interesting cases which I am dealing with right now is for an MNC where the tolerance limit of the turbines. I think I gave you an example we are aware of is half a MM. So when you design turbines, the tolerance is 0.5 MM. Now ultimately the turbines are going to sit on a foundation which is located on the ground. Imagine if this type of situation happens, what will happen to the turbines? How would you run them? So this is where the industrial activities get too much influenced by the stability or instability of the ground or the soils. Look at this situation. Again as I said the oil tanks are the economy of the country. You know if they are flourishing, economy is flourishing and that is the reason the western part of the country is flourishing as compared to the other parts of the country because we are into the oil business here alright. So we dictate the terms with the international market. Unfortunately the place where you are storing the oil sometimes might be undergoing heavy distress in the form of the settlements. So in case the settlements occur in huge structure the other day I was giving in a dimension of a oil tank is about 50, 55 meter diameter. Height could be anything from 30 meter to 45 meter depending upon the storage and the amount of land which you have. So this is what is going to happen. Your tanks are not stable. I will show you some other picture also. Sorry this is the one. Look at this. The overhead water tank you know is differentially settling. So if you have a very close view on this you will see that the whole tank is settling on the one side and it is cracking also from the base. Again because of the poor soil conditions. Siloes I do not know how many of you are aware of silos. Siloes are the places where you store grains alright fertilizers granular material. So there is no difference between sands and wheat and rice and sugar they are all granular materials for me. So the way I would like to store rice the way I would like to store fertilizers I would like to store sugar also there. So these are the silos which are huge structures. They could be for army also. I might be storing their missiles. I do not know whether you are aware or not place very close to Bombay has these type of silos where often strategic importance. So there they are storing something different. Now look at this this soil erosion is occurring and these are the transmission what do you call them power houses. Power houses alright. So this is where the foundations of most of the power structures are located. But because of the soil erosion what is happening all the structures are in a dilapidated condition. How would you deal with this type of situation. It is a strategic situation. All these things are related to each other. The piles have failed and hence the podiums which you create on in multi-storey buildings they have also collapsed. Go and see these places then you will learn what is happening over there what the problems are. So I am sure you can realize over here that these are the piles which were straining some compacted soil mass and some of the piles have failed. So that means the soil which was retained over here to create a you know important structure above the ground because of some reasons this system is going to fail that means you cannot lay the foundations for those type of structures. We call them as lateral earth pressure. The soil which is retained on the right hand side of these piles these are known as piles. These are the structural elements. The pressure is so much or maybe because of the erosion the soil has moved out and the piles have failed alright. Most of the buildings in Bombay city are at elevated podiums and if you go and see next time onwards you will realize what I am trying to discuss and why this was in the newspapers. This is something very interesting. I do not know whether you are aware of this or not soil nailing. Did you see something of this sort when nailing has been done to retain the hillocks the stiff cliff the nails have been embedded to stabilize the slopes. By the way all these nails are wrongly done and that is the reason the collapse has occurred. So this becomes a case of litigation. The guy spent money and it failed. Who is responsible? So there are several cases the more and more infrastructure is happening the more and more problems are being observed becoming a critical situation. So here the slopes were stabilized but the entire thing has failed. Look at this this is the road failure again because of the inadequate drainage. So both side you have water bodies and or the same water body and this was reclaimed. You did not allow drainage to occur water has found its own path the road has collapsed. This is another good example of how building settled. I was talking about when we were discussing the staircase has completely got detached from the building. The plinth has cracked the building is going in as a matter of few days when this will be in the national network. This is a beautiful example you know the staircase are still hanging in air and where they are supposed to be the entire thing has settled down but very uniformly Grace got added potential I will show you what happens then. So we are going to do all these analysis. We are going to study these things how to find out how much settlement has occurred whether the building is safe or not and so on. There is a beautiful example of other side of the building which I showed you the whole building is settling down and there are cracking taking place you know all along the building from the plinth and so on. I do not know whether how many of you have seen such type of structures in bombicity. Most of the oil tank forms are having this fate. Had it been water tank I would not have bothered so much crude oil hydrocarbon. If it collapses it is going to be an absolute disaster. I hope you understand why. Clear? It is not only that is going to fall on your head. Before it falls on your head it is going to be a time bomb. It will catch fire and God knows what is going to happen may explode even. So this is the modern day civilization and one thing is sure people have ignored soils completely. They thought that whatever is sitting beneath is not going to be problematic ever but it is not so. All these structures remind you that what is the importance of studying the issues related with soils and rocks and the subsurface. This is a very close look at what will be the problem if this type of situation occurs in the tank forms. All the piping arrangements which have been done are defunct. They have cracked. Why? Because you are designed these pipelines to be connected to a certain portion of the tank. Now when the tank settles these pipelines have got sheared off or veered off or they have got cracked completely. How many of you have come across this type of situation? Now this is known as soil subsidence collapse. We also call it caving in and the sinkholes. You must have come across sinkholes. This happened at Sakinaka about 5-6 years back. This is the story of 3rd August 2019. So the Gurgaon traffic severe line running underneath road and the water from the rain might have weakened the road causing it to cave in. It is happening very frequently. Read about this process. Why it is happening? Another interesting case you have to concentrate on the picture to realize what is happening here is because of complete water logging. Look at the parking is here. The whole thing is a big crater which has got formed. You know this is the pedestrian pathway. These are underground utilities in Japan. So this is the road pavement and the whole portion a big chunk and this is also by the way the road you can see the remains of the road. So this was connecting earlier over here and because of excessive rains, water logging, seepage, the whole thing has caved in. This is what is known as sinkhole or caving in process. Why? We will try to answer this. Look at this. Complete website is devoted on sinkholes. I hope you can realize what is happening over here. It is so dangerous. Now what is written over here is sinkholes also form due to the human activity such as collapsed abandoned mines. You are getting this point. So the more and more mining operations which are occurring and then you are trying to sustain the present-day society, this is what is going to happen. This is a beautiful thing to see. Look at this. At the middle of the road, there is a huge crater getting formed and because of what? I have dealt with few situations in Bombay city also. There is another interesting situation which might be this again from Tokyo. So if you have to analyze these situations, you have to study the mechanics of the material which are being used for creating these systems. Typical landslides, Bombay-Puna highway is famous for this. Go to the northeast every day occurs maybe in parts upper reaches of JNK, the big problem is landslides, road getting blocked, closed and so on. How would you stabilize them? How would you create these type of roads for our countrymen and so on is a big question. It is a beautiful scene. I do not think, have you ever seen this? Have you ever gone towards upper reaches of Srinagar? I do not know whether you can realize this or not. These are the big boulders and this is the highway and imagine it is only a matter of time when this boulder is going to fall down. Very good example of Badrinath and Kedarnath. When you travel from Deradun towards these sites, every now and then big boulders, every now and then these boulders fall on the cars and moving vehicles and so many people die, they do not even report it. Chardham Yatra, these are the transmission towers. I think there are several cases in India where you know transmission towers get uprooted and these transmission towers are the ones which are carrying electricity from hydroelectric dams or units. It could happen because of the wind, it could happen because of big foundations. Here what has happened, the entire foundation system has got uprooted. So, what you are seeing over here is a foundation. Now, because of the moment and the torque which has occurred on the entire tower which is about 50 meter high, weighing about 40 to 50 tons, all right, steel, the whole foundation has got lifted up and collapsed at the cut. This is what is known as uplift failures. It is a loss of contact between the soil and the foundation, okay. How would you handle this type of a situation? The RE wall failures, you must be reading in newspapers. There was a video also recently that the RE wall has failed somewhere. This is a good sign to see that how RE reinforced earth wall. This RE means reinforced earth wall. It has failed. Look at the cracks which have developed. Another beautiful example of how RE wall has failed from the foundation itself. The soil which you have filled up inside is getting washed out. Now, this is the time of the construction of the highway. Anyway, the essence of the story is that half of the road has collapsed and these are the real life photographs. Poor filled material or maybe lack of compaction or whatever. Look at the whole system has cracked, the foundation failure. Another view of the same, you know, which shows you how the entire road pavement has collapsed. The foundation soil has yielded and hence this tragedy has occurred. If you see from the other side of the RE wall, then you will see that how the collapse has occurred. The filled material has come out of the wall, panels have dismantled and the wall is defunct. Remember, each of these projects is going to cost at least 40-50 crores and once these type of things happen, there is no retrofitting. You cannot retrofit anything. You cannot make them overnight. So, it is a loss of time. It is a loss of property. It is a loss of time, money and whatnot, inconvenience to people because when this was being constructed, people were facing problem. Now it is defunct, people are facing problem. I cannot dismantle and throw it away anywhere. So, these are the issues which have to be borne in mind. Some other shots from different angles. You are doing investigations to see what went wrong. This is an interesting phenomena. I do not know how many of you have really seen this, sand boils. I think you were discussing about this. This is a very peculiar condition which happens in the deposits, you know, which are prone to liquefaction. We were talking about alluvial soils, very notorious. This is what happened in Ahmedabad. You know, building is intact. The entire thing got uprooted from the foundations. Very sad. This is what I have been discussing in the last lecture if you remember. You know, dissolution. Somebody asked chemical processes. I do not know. Somebody was sitting over here. And he was discussing about this chemical processes and I discussed about the dissolution occurring in the limestone because of the humidity and sea action at extremely high temperatures. So, this is one of the situations. So, most of the Middle East, Gulf countries, Oman and all these places, the big problem is you want to develop infrastructure fine. It is a beautiful sandstone limestone formation adjacent to sea. Sea water interacts with these formations, very humid climate, extremely high temperatures and sea water has lot of salinity. Clear? Chloride content, sulphates. What do they do? They start eating up these formations. So, this is one of the examples of chemical processes which are destabilizing the soil mass. Now, it is very difficult, first of all, to diagnose how deep these cavities are. You cannot keep on changing the plan of your building. You agree? So, by the time you go and start executing the job, you will realize where the columns are supposed to be and where the foundations are supposed to be there, you have a cavity like this. Unfortunately, these cavities cannot be sealed even. You start pumping cement concrete, millions of tons of cement concrete will go inside, but you cannot close them. There is a very famous hospital in India, particularly in Delhi where this happened. Try to find out the history of that place and then we may discuss. Go to place called Pisa in Italy and get a feel of why I am asking you to go there. It is a 4 degree lean. By the time you go and sit on the top of the terrace, you literally realize that yes, your CG is getting affected psychologically. It has been retrofitted, are you aware? But it has been left as 4 degree, why? Because if you make it, if you correct the settlements, then nobody will come over here. And this is a big tourist place, I am sure most of you are aware of. The wonder of the wonders is that the building is intact, no cracks, nothing and it stands there. Whenever you get time, please go there and then you will learn a lot of things related to this. This is what happens when you know geomaterials are ignored. These are the slides made by Lijit. So, this is what happens. The entire building has toppled. Fortunately, this has not happened in Japan. This is the recent one. He is also from Kerala by the way. So, he has contributed this slide and it works. This is the recent phenomena where the dam has burst. This is a recent failure in Brazil in January 2019. And as the aftermath of this failure, the entire dam has burst, you know. And then like manmade lava which you are talking about the other day, it has gone tens of kilometers. It has just flown like a lunge of the residues or the mine tailings which you are talking about. So, anyway, so coming back to the point, when you are doing infrastructure development in problematic soils, challenging soils, getting a solution is very difficult. And this is what I will try to address when I am discussing this course. What are the major issues? Just to sum them up quickly and particularly to avoid failures, we have to learn from failures. We will be talking about soil investigations in this course for infrastructure development projects, roads, road widening projects, ports, powerhouses, fertilizer plants, specialized facilities and so on. Establishing the subsurface profile so that we know where the hard strata is and we can lay the foundations. You are doing, you are not doing foundation engineering course. That will be in the fourth year. So, once you have the basics of soil mechanics, geotechnical engineering, you can use them in creating the best possible foundation system. Anomalies are very important. So, when we are trying to establish subsurface profile, anomaly, I showed you one anomaly, you know, like big, big cavities getting formed because of the solution. Geotechnical exploration and sample collection, I will try to discuss this also. What are the techniques which are used for geotechnical exploration and sample collection? And once you have retrieved the samples, how would you test them? Just like pathological examination which most of the doctors rely on. And of course, the last issue would be, how would you ascertain the suitability of geomaterial soils and rock for construction? And the question is, if you find that these materials are not suitable, how would you go ahead with the project? So, this is where the engineering and technology comes in.