 So, we have been discussing a lot of things regarding geotechnical engineering one starting from, starting from origin of the soils and rock cycle, different type of soils, their classification system. We have talked about how do they originate, how do they get form and how do they get deposited. Now in today's lecture in continuation with whatever we have been discussing, I will give you some examples of the transported soils which are quite useful in modern day geotechnical engineering. So, if you remember geologically we had differentiated between two types of groups, one is transported, another one is residual. I think I cited examples of residual soils and in today's lecture, I will be talking about the transported soils and some of the examples. See first in the category is Lewis, we discussed about this in the last lecture also, so truly speaking these are the wind blown deposits, sometimes we also call them as Aeolian, they are weakly cemented, so for all practical purposes these are the loose materials. And when we talk about the cementation, mostly this is the calcium carbonate bond, sometime back I had talked about why desert sands can be utilized as the construction material particularly in concrete. I think now you can get the answer that most of the Aeolian deposits or the lowest soils, they have weakly cemented calcium carbonate bonds and this calcium carbonate can be utilized for making concrete alright, because of the Pozzolani city. Normally, these type of soils are formed in arid or semi arid deposits, so arid regions are the ones where you have dry climate particularly like deserts. And the beauty of these type of deposits is that these deposits stand in almost vertical banks, so most of these deposits are almost vertical, so if you see the sand dunes, so the whole intention is that whenever you get time please go through it and some of the questions which you are asking about the reclamation and you know land creation, I think I have given some examples. I think I also gave you an example that most of the oil deposits in present day circumstances are located at these type of soils. So the big issues are how to make these infrastructure which are going to sit on this deposits table, because the keyword here is you know it is a weakly cemented material and if you remember when you are talking about the fundamental properties of the grains, these are the grains which are very light in weight and particularly if you look at their microstructure which we will be discussing maybe after 2 or 3 lectures, you will find that they have lot of furry structure on the surface. So if the surface of the particle is like this, it is not going to be as smooth and as spherical as the river transported sands would be, here you will find lot of furs on the surface. If you look at the microstructure of this particle and this helps them in getting airborne, alright when wind comes and they form a near vertical bank, let us introduce the word near vertical. The biggest difficulty here is these systems keep on moving, you know sand dunes they keep on moving or shifting and because of this it is very difficult to lay the foundations on them or make a structure on them. This is one of the reasons why there is no clear cut boundary between the 2 nations, our neighbors and ourselves. I hope many of you understand this was interesting project which was you know I was contacted by BRO but then the difficulties are I hope you can understand we are not very much accustomed of living in dust storms, so you have to spend some time over there. So when the sand dunes keep on shifting the big problem is how would you lay the foundations alright and that is one of the reasons that why we do not have a clear cut demarcation of the boundary between the 2 nations. Geologically I hope you will realize that most of these deposits are coming from the desert which used to be a water body, so that is a connection between, see the question one of you should have asked from where the calcium carbonate is coming in this type of soils. So that is the link and long back one of you had asked this question regarding you know tracing the rock minerals, the soil minerals, so this is a keyword how do you make sure that the soils have calcium carbonate, so calcium carbonate is a peculiar mineral I would say I am using the word mineral clear not the oxide and the salt. Now this mineral is coming mostly from the marine environment and hence this becomes a part of the entire lowest system. The second in the category is what is known as a tuf have you come across this word ever check it on net and find out apart from the soil where else tuf has been used, the soils coming out of this is tufaceous soils check it in the meantime and there was a very famous case also which was going on related to the tuf did you get it, it used to be a denim cloth and there was a company known as tuf alright and then there was an interesting litigation going on and read all those stories there. These are basically small grain slightly cemented volcanic ashes and they are mostly transported by either wind or water try to check out whether we get tuf deposits in India or not whenever you get time please go back to your hostels and check where these deposits are located though I have given you a link also and you may try to understand which part of the country you come from and what are the soil deposits at that particular location. Sometime back I was telling you in modern day science and technology you know after asking your name the second question would be you come from which place what type of soil you have there what are the challenges what are the problems in case you have to continue in this profession so that becomes your introduction you understand the context changes very fast so after your name the place which you belong to now by virtue of your studies you are from Bombay so you should be aware of these geomorphological conditions which prevail in Bombay city alright the third in category is bentonite I think I have already given enough history about bentonites these are the deposits which are mostly available in the western part of the country Bhuj area is very famous for this atomic industry depends a lot on the bentonite and even the construction industry also depends a lot on the bentonite why because of the thixotropic behavior so this material is thixotropic in nature what is thixotropic so suppose if I take a small sample of this material in my pump add 2-3 drops of water alright and then let it become saturated and if I temp it alright if I disturb it what is going to happen the water gets oozed out that means there is a segregation of water with this material which is bentonite and again if you leave it for some time the material again gains strength alright so this is a fundamental property associated with the minerals and incidentally bentonite happens to be belonging to the family of Montmorillonite we will discuss about this later alright so these are the type of minerals which are very notorious and in conventional subject they have always been termed as unwanted materials not bentonite the Montmorillonitic material so those of you who come from Vidarbha region central part of Maharashtra MP Karnataka you know you must be seeing black cotton soil there so the constitution of the black cotton soil would be a cousin brother of bentonite but by virtue of this material having thixotropic effect this has become a boon in the nuclear industry and we will discuss about this if time permits so if you want to dispose the atomic waste which is having very high radioactivity which is having very high chemical concentration which is having very high temperatures this deposits are going to be the best deposits or I can create a system where I will use this material as a buffer material check what is the meaning of the word buffer if you read some papers on the net there is lot of research going on internationally in the subject so government of India spends lot of money in characterizing the bentonite from different parts of the country and checking their worthiness as a buffer material for waste disposal which is highly toxic and hazardous alright now buffer is something I am sure you must have used this term in the chemistry alright if I want to maintain the pH of a system I have a buffer tablet of 7, 9, 6, 8 whatever so truly speaking in this case what happens is the buffering is between the waste unit canisters which are made up of lead I am sure you must have done your 10 plus 2 physics or chemistry because lead happens to be a retardant so I will contain all the waste in the lead canisters cansters are nothing but the containers I will bury them deep inside the ground 150 meter 200 meter depending upon the type of activity which I have in the waste and then cover it with this material to make it more workable I am using a word workable that means on its own this material cannot be used much alright so I will have to add something to this now this becomes engineering with the soils clear so we will add something to this we will make good buffers and this becomes the best possible disposal place for atomic waste read more and more about this I will not be getting time to discuss much about these things but the second course which I offer for PG's and earlier undergraduates there I used to teach about the geomechanics of atomic waste disposal the fourth category would be or the fourth transported type of the soil would be a glacial till tillage is something which is known as this remains tillage alright so when you say glacial till this is the remains which is coming out of the glacial activity in one of the lecture you are talking about avalanche if you remember so avalanche is one of the reasons for causing the glacial till so in the mountainous regions if you go towards Manali, Rotang Pass and all those areas a big problem would be you know how to deal with these type of soils and I will show you some of the situations in today's lecture they are also known as the bouldering clay so those of you who come from Himachal Pradesh in particular alright or maybe upper reaches of Himalayas or the lower reaches of Himalayas you will realize that the big difficulty there is to lay the foundations why because these type of materials are having a combination of a clay fraction which is very fine particle and boulders which are very big in size clear so I cannot sit on a boulder earthquake comes these type of deposits are going to get destabilized very fast so that is the reason that unfortunately most of the cities and towns in the hilly regions of the country have remained undeveloped or underdeveloped I remain this point these areas have been ignored completely so these are deposited by the glacial activities try to find out what are the major projects which are going on in the Himalayan regions nowadays can you name some of them major projects very important question alright you should be knowing all these things big big tunnels which are being inaugurated or which have been inaugurated instantly remember those names alright so this is all about the application part which cannot be taught in the class as such so these glacial tills are the glacial activities and not transported or segregated by water very difficult deposits of the soils to handle then comes the warped clays any idea what these type of clays are see nature also does miracles I hope all of you will agree with this and if you really want to enjoy the miracles of the nature the geomechanics geotechnical engineering of the soil mechanics is the right subject to study now what happens over here is it is nature shows patterns of formation so what happens is there will be a layer I think we should start on the bottom most portion there will be a layer of a material second deposition on the layer third and fourth and this happens in a pattern and this pattern is dictated by the climatic conditions so if you have silt clay silt clay we will discuss in details that what is meant by silt what is meant by clay so today what I have done is I have introduced another term in the realm of soil mechanics that is silt to understand quickly silt clay boulders are nothing but the sizes of the soils or soil particles clear so these are types of the soils depending upon their physical attributes nothing more than that so if I use the classification system that how the particle size looks like or what is the particle size what is the shape what is the morphology under this category this type of a deposit comes now it so happens that whenever there is a warm weather silt gets deposited and whenever there is a cold weather the clay gets deposited so every 6 months you know when the weather changes the deposition pattern also changes so these are basically alternate deposits the thickness of these deposits could be substantial few tens of meters even I think now you can realize what is the influence of the environmental activities on the formation of the soil alright normally this type of things happen in fresh water and lakes alright this could also be the outwash from the glaciers whatever gets washed out from the glaciers now silt deposition occurs when the system or the environment is warm plus heavy runoff however the cold weather is during sorry the clay formation is during cold and less runoff truly speaking this type of deposits will be forming in few years so you might be having a geological time associated with this which could be of the order of few years there is another category of the transported soils which is known as marking check what is the dictionary meaning of the word mark mark basically corresponds to the marine environment and what is marine environment a Bombay region is a marine environment alright wherever you have coast wherever you have seashore clear so the land side is known as onshore and towards the sea it is known as offshore so marley soils are very fine grain materials and their origin is marine environment there is another category which is known as gumbo gumbo these are very sticky materials and when soil is going to be sticky it is also going to be plastic in nature and dark colored see I have intentionally used the word here plastic you must be wondering what is meant by this plasticity of the material so we will study in details about the plasticity of the material plastic material is the one which can be molded the way you want so when you are a kid still you are a kid no doubt but when you are very small kid what you used to do you used to take a file add some water and then you may say make a ball out of it is it not so that comes because of the plasticity of the material for the guys who are in agriculture the way they differentiate between a good soil and a bad soil for agriculture would be simple test they do not require very high file laboratories they will take soil add some water and form a let do out of it clear or a ball out of it and then what we used to do when you are kids we used to throw it and let us stick on the wall is it not if you have not done it do it right now the right time to learn about the materials if it remains stick over there it shows that it has some properties which are plastic in nature after sometime it may remain there or as the moisture goes out of it it may fall down clear so these are the properties which people will like to look at when they do construction with the soils and remember soils are the materials clear I can use them the way I want to I can create a situation and I can use it I cannot say that I am not going to do my engineering over here in this type of deposit is this correct and that is what the engineering with the materials like soils would be I have used the word dark colored in nature remember sometime back I was discussing the difference between transported soils which are crystal clear particles very fresh looking pinkish brownish color yellowish color but now there is a situation where transported soils of gumbo nature are dark colored also the reason is look at the history of formation they got sticky property very plastic in nature and they might be interacting lot of bacterial activity in it and that bacterial activity under anaerobic condition might be giving the dark color this is also situation there is another interesting category of the soils which is known as peats have you come across this world you get a chance to go to Scandinavian countries and if you have to live over there check it out on net it is a beautiful phenomena where peat deposits they get disintegrated so imagine today your jimkhana ground is intact clear but tomorrow morning when you get up you will realize that some part of this jimkhana ground has vanished there are a lot of videos which are available on YouTube check it where these type of deposits are now this type of disintegration happens because this material is of highly organic in nature lot of organic matter is present in this type of soils alright and this organic matter disintegrates so we call them as organic soils for me there is no difference between these type of soils which nature has produced and the soils which I am getting out of reclamation and rehabilitation of landfills this is okay so nowadays the business is to rehabilitate the landfills check it it gives you a very good opportunity to start your business rehabilitation of the landfills how many major landfills India would be having right now every city would be having at least one or two Delhi is a blessed city how many landfills it has three four major ones which are always in highlights national network why so what happens in the last lecture we were discussing about the issues related with organic matter so the more and more organic matter decomposes what is going to happen yes one of you very nice excellent so this is the source of very good then what will happen yeah so the more and more CH4 emission takes place what is going to happen true one is greenhouse effect next as a civil engineer geotechnical engineer I am really not much interested in this I am more interested in the mega problem so they are the landfills who are falling they become unstable they catch fire here so most of the time these landfills are burning so what is going to happen if they are burning all the time so next time when you go to Delhi these three famous landfills what do you notice there most of the time they are burning and when they are burning what is going to happen they are emitting carbon dioxide knock socks and the environment and particularly in the cold climate during November to February what is happening then major problem so I need not to go to natural deposits see as a human activity I have created more and more storage of peats or peat like material clear 2-3 examples of what PT type of material would be the organic material could be naturally deposit forming a peat manmade activity CH4 the landfills might catch fire this is okay and once it catches fire it becomes unstable it is okay peats normally would have order one of the interesting things about the peats is that these are fibrous in nature whenever a soil or a material exhibits lot of fibers present in it what is going to happen you are discussing this other day what is the problem associated with this the presence of fibers organic content they have water holding capacity I think we discussed in the last lecture so the more and more organic matter you have in a soil mass it will be holding more and more moisture is it good or bad you are right it is bad but why yeah so there is no absolute answer remember the profession changes and good or bad changes so the guys who are doing you know forming of let us say rice you must have seen the way the forming of rice is done what is the need they excavate the soil they put lot of organic material into it why it should be holding more and more water go to the northeast where tea gardens are present so I am sure you must be aware that tea gardening requires lot of water and that is the reason he is normally produced in the regions which are having high rainfall so whenever you have this type of materials which are fibrous organic in nature they would have very high water holding capacity the more and more the more and more water holding capacity is the more and more disintegration is going to happen the more and more disintegration occurs all these issues are going to become major problems is this okay as far as engineering is concerned these type of deposits are a real challenge to handle why because they are extremely compressible these are extremely compressible materials so no wonder when you hear you know some of the buildings settling down the first floor second floor going inside the ground floor all right the first indication would be that the soil which is present at that location must be organic type okay for R and D guys this is a bliss those who are into R and D check it out on net there is a big group which is working on restoration of PT soils restoration of peats is a big challenge and become an expert in the subject there are not many guys in the world who are working in these areas and I am sure that you will realize very soon that most of the countries have a big challenge in terms of the PT deposits so the big question is how do you restore them I think this is a UNDP program also where they are trying to safeguard the cities and the country which are mostly located on PT deposits now one of the ways of doing this could be I am just giving very vague idea do not quote me tomorrow anywhere all right what would be the vaguest idea to stabilize these type of deposit cut off the supply of oxygen how will you do that wrap them in a polythene how would you wrap the entire soil mass on with the big big buildings are sitting in the polythene's imagine are you realizing now this is where the surgery is required so most of the geotechnical engineering guys who are in the profession become surgeons of the soils and the situations because what you have to do you have to give a solution so they are very interesting ways of dealing with this material and try to read as much as you can what bacteria is going to do on arguing matter I think now you understood so the more and more bacterial activity you expose this material to you are inviting more and more problems here that is what I was saying you contain the whole system cut off the oxygen these guys can survive there you agree unless they are anaerobic are you getting this idea so the moment they become anaerobic different problem the more and more you are going to produce this you can do anything then you have to do something different so suppose if you are doing this activity make sure your answer was incomplete you say that my answer was incomplete it is not incorrect so what I will do is I will create a situation where this activity happens to be under anaerobic systems greater depths where the oxygen supply is less clear but still they will disintegrate another thing very early for you to catch these concepts of the subject precipitation of any system because of the bacteria in fine grained soils like clays is going to be absolutely difficult because the pore sizes are extremely small somebody wanted to ask about this pore size or something I asked you to write up the back of your notebook anyway this is one of the answers clear so another category is muck these are basically fine particles and this is the mixture of inorganic soils see muck is a term normally we use it as a miso number for slush is it not it is a mucky thing mostly these are black decomposed organic matter also so it is a mixture of inorganic soils and black decomposed organic matter normally these type of systems you will find them accumulated close to waterlogged areas all right particularly and swamps there is another category which is known as humus so suppose somebody asks you question what are the organic soils which we have come across peats are number one muck is number two humus is also organic material all right these are mostly dark brown these are organic matters and this is the normally top soil of a deposit the one of the characteristics of this material is that this would be having partially decomposed vegetation in it one interesting thing on a philosophical side I hope you can realize that the soils are normally made by nature or natural process but nowadays people are talking about the manmade soils also so the moment this municipal solid waste comes in the picture you know the humus is normally occurring naturally but most of these characteristics are also present in the remains of municipal solid waste clear and hence there are many guys who are directly rehabilitating the landfills and they are using the remains of the landfills as agricultural material it is a big business then there is another category hard pan as the name suggests these are going to be the hard deposits and sometimes mistaken as the rocks later on you will study one of the tests to confirm whether a material is soil or rock is to take a small sample and soak it in water if it disintegrates over 72 hours it falls in the category of the soils if it does not it falls in the category of the rocks so you are asking this question the very first lecture where to lay the foundations it may so happen that when I am doing investigations I may come across this material or deposit it is very hard and I might mistake this as a hard strata rocks clear but subsequently when you excavate the soil it might get disintegrated very fast okay so this is the property though it is a hard deposit having cohesion I hope you understand the word cohesion cohesion is something where the particles of the soils are you know cohesed they are they are bound with something so that is what is known as cohesion all right so if two particles suppose like a glue I have two particles I will put glue on both the particles press them they form a matrix so this material shows cohesion cohesion is something which indicates that the particles are glued with each other and the acid test of this material would be soaking in water acid test means you have to differentiate this material with the rocks and this is one of the best ways to differentiate there is another category of the soils which is known as colluvial soils check it on in the dictionary what are the meaning of the word colluvial the other day we are talking about alluvium now it is colluvium what is the meaning of the word colluvium so when you travel through Bombay on Pune Express highway Khandala Ghat is very famous for rock debris is falling during the rains is it not so we say rain induced slope failures so you are right the colluvial soils are the ones which are formed because of the accumulation of rock mass when they get detached from the parent body and the parent body is nothing but the rocks all right and they get deposited over there we call them as accumulation of rock debris what are debris discards all right construction debris for that matter we also call them as tallest this is the name of the soil tallest and mostly they get deposited at the base or the foot of a cliff you know what is a cliff almost a vertical system of rocks all right near vertical so those of you might have gone to Sub-Shanghi very close to Nasik the rocks are cliffs near vertical so suppose if I draw a system of rocks like this all right now this is a cliff it is not a slope so the beauty is that most of these are the disintegrated accumulated rock debris at the foothills also known as tallest we are from Uttarakhand which place Dharadun very good have you ever driven from Dharadun towards higher reaches let us say towards Badrinath Kedarnath and all these areas yeah so what do you find is there some similarity between what I am discussing here and the type of problem these guys are facing in the regions of upper reaches of Uttarakhand correct what are the difficulties you have huge accumulation of these materials so you cannot even there the foundation you cannot make the buildings this is manmade also by the way they are chopping out all the hills okay and another category would be mind tailings is there anybody in the class from let us say eastern part of the country Belai Jamshedpur you are from which place what do you see normally when you pass through a railway railways on both the sides of the railway track what you see during night time particularly nights you are not observed see civil engineering is all about observations so if you do not have observations unfortunately nobody can make you a good engineer and technologist and civil engineering what I am trying to hint at is most of the mining activities alright thermal power plants are in the vicinity of Jamshedpur so what you see is when you pass by the railway track both the sides of the railway tracks are having huge dumps and some of these dumps might be you know having fire some of these dumps are the mind tailings so you take out the mineral from the mines process them extract the you know good part of it which is useful to you 80% remains unutilized throw it somewhere clear human activities soils form because of the human activities so mind tailings are the one mostly these are silty materials anybody in the class from Jharsi Guda area Jharsi Guda no check it on net why Jharsi Guda is so important for for India being a muscular nation you understand what is the meaning of this India being a muscular nation still makes you muscular and apart from that those days are gone when is still used to make muscular now what is happening nuclear power nuclear energy weapons medicines clear radiotherapy different types of radiations which you are using for agriculture and so many things so Jharsi Guda is the place where most of the what type of mines are available link the two things uranium very good clear so the more and more uranium India wants what's going to happen I use some figure I said 30% 25% is useful rest is all discarded tailings clear so the more and more mining you are doing any type of mind the more and more discards you produce so these discards are being just dumped anybody there from Roy Raiapur Korba airport near Korba very good so what do you see in Korba region man-made mountains you have seen or not very good I'm sure I'm happy at least one person is aware of what's happening so the more and more mining happens the more and more man-made hills are getting created so I'm sure your kids will not go to Himalayas for whatever amusement they will say these are the Himalayas created by sale people alright and TPC guys and so on and this is a big business by the way start rehabilitating these man-made mountains this is what is coming in practice now people are trying to rehabilitate them and leasing them out for different amusement purpose so it so happens that the mine tailings are the silty materials and they are hydraulically filled and you read this hydraulically I don't know whether you are aware or not conveying soil hydraulically is filling of the mine tailings so if I am transporting the soil hydraulically and creating a beach is reclamation alright the principle remains same so I will take a pipe I will mix the soil I will pump it I will fill up the land the mine tailings which are coming out of the industrial process very fine particles I will deposit them in ponds they are hydraulically this becomes mine tailings clear lot of similarities are there see it is very interesting when politicians meet they talk about politics when two geotechnical engineers meet they talk about the soils as I please come to our place and I will take you to the deposits of these type of soils you understand so this becomes a Dharma see when we talk about the deposits of the soils regional India is an interesting place you know why because in our country we have several deposits of soil which is very very rare you won't get these type of deposits everywhere in the world because most of the country they are so small that they won't be even sitting on one deposit of the naturally occurring soils so these deposits miss mostly depend upon the type of climatic conditions by any chance you who is from indoor you said you are from indoor indoor is becoming a hub petrochemical hub of the country you agree with the statement so it depends upon the climatic conditions it depends upon the topography and this also depends upon the geology of the formation so first in the category would be marine deposits because we are sitting in Bombay the coastal region and