 comes the issue that you know how what is meant by the response of soil to the environments different type of environments I think I had discussed about you know soil and structures they interact with each other we call them as soil structure interaction and soils are used to create structures and sometimes structures are created in the soil mass or sometimes the structures are created on the soil mass clear. So laying the foundation is on the soil mass making embankments different type of retaining structures with the soil mass and when you are creating conduits cavities tunnels this is inside the soil mass. So soil structure interaction is a very interesting question which people are trying to address yes each of these statement which I have talked about on, in and with has environmental attributes associated with it clear. So when you are talking about the aerobic and aerobic conditions as deeper you go in the soils you will be having switch over from organic to inorganic situation alright this is a good example. So different type of environmental conditions might be associated with the systems which you are talking about. Now pore fluid is the one which is present in the pores in the form of either gases or liquids or the combination and present day you know way of looking at this is when you when you derive a parallel or equivalent between the human body and the soils is if I can diagnose you by taking some sample of your blood alright similarly I can diagnose the soils or geomaterials by taking a sample of pore fluid. So pore fluid is the one which is present in the pores either in the form of the liquids or in gases we will discuss this in details how to extract pore fluid because they are your syringes may not work what doctors do is very difficult to take out pore fluid from the soils. So what type of techniques are used to sample pore solutions from the soils and the geomaterials it could be concrete it could be rocks it could be soils this has to be studied in a very very different manner. In other words the pore fluids also depict the state of the environment which is present inside the soil mass clear the temperature the pressure the humidity the type of bacterial growth under aerobic anaerobic condition the type of gases which are getting formed are an indication of what type of processes and the mechanisms are happening in the soil system. So pore fluid characteristics are becoming very very important to discuss interaction of soil with heat I think I gave you ample examples you know when soils come in contact with elevated temperature this could be a forging unit this could be something like you know you might be having a furnace foundation for a furnace or you might be having a rolling forging unit somewhere in the industry where the hammer drops produces a lot of heat rocket launching pads you know different type of cables which are buried inside the soils for industrialization most of the time when you do ground improvement you inject chemicals in the soils and these soils might react with the chemicals. Nuclear waste disposal is a good example of how soil heat interaction occurs nuclear waste is at elevated temperature. Similarly the leachers which are coming out of the landfills might also be at elevated temperature and this might react with the soils alright so I am sure you must be realizing that these issues these type of interactions have not been discussed until now in the conventional subjects because the conventional subject was devoid of the environmental conditions in which the soils are living are located alright. So soil chemical interaction I am sure now it is clear to you contaminants getting discharged either inside the soil or on the soil mass would create a soil chemical interaction and we want to see what happens after the interaction occurs soil bacteria interaction I gave you ample examples you know pathogenic discharges if these sludges are not treated properly and if you take out these sediments and pile them up somewhere this is going to become a part of the geo environment environment. Soil root interaction I think we discussed about this so those of you who might get a chance to work in stabilization of soil based on vegetation is picking up and this is being done at several places in my consulting also I have used this concept of soil root interaction at different tailing ponds in the country and where I have recommended vetiver grass if you are aware of vetiver grass vetiver is the name of the grass it grows very fast and the roots penetrate through the soils vetiver v e t i v e are vetiver. So this is a variety of the grass which is you know quite commonly available or you can transport it and you can you can grow it on the slopes of or the embankments. So the beauty is the root acts as an reinforcement and it holds the soils so you check the photographs I will also show you it is a good example of how soil root interaction occurs. If you look at the physics behind this roots produce suction alright and when suction gets created truly speaking this becomes a soil suction interaction clear a three phase system that means the pores are now filled up with air water and this dynamics of the air and water guides the properties of the soil. Similarly soil bacteria interaction also does the same thing bacteria might be producing gases because of decomposition of the organic matter and once these gases produce and they remain in the soil the whole system becomes very susceptible to temperature and pressure alright. So these type of dynamics people are studying then of course soil electrical electric or charge you may say interaction. So soil heat and soil electric phenomena could be coupled also passage of current through a conductor produces heat alright. So this is a very interesting mechanism where people would like to study what happens water present in the soil is a dipole clear it is a polar material polar liquid. So now if the polar liquid gets exposed to the electromagnetic field how the properties of the fluid themselves will change alright. So these type of things become very important when you are talking about different types of sensing tools which you are using them whether electrical signals are used to detect something in the soil mass I will talk about this separately in the form of electrical characterization of soils, thermal characterization of soils, chemical characterization of soils, biological characterization of soils and so on. The last in this series would be the soil and liquid water interaction. So I am sure you must have come across the soil which contains water and this water is of different types we call this as environmental water also we call this as a you know gravitational water, free water, bound water, adsorbed water. So these type of concepts are becoming very, very pertinent in discussion nowadays. So just to show you some of the examples of you know how this is being done I think this is what I have been talking about I will show you few cases where the type of problem which I am dealing with you know this is a beautiful example of the problem with which most of my students are related right now. Indulco industries is the largest industry in the world which produces alumina and production of alumina is because of digestion of bauxite. So whatever residues are left over this is known as red mud. Now the question is where you are going to throw the red mud. So this is becoming a big problem for the society and hope you can realize that a lot of dust is there and you know the disposal places have to be defined very clearly and if you see you know these are the red mud ponds and I do not know how many of you have visited such type of red mud ponds there is a huge area about 100 acres land where the height of the landfills or the height of the disposal ponds would be 40 to 50 meters. So it is a huge challenge you know the more and more bauxite which you are digesting to produce alumina the volumes of the red mud which is industrial byproduct is increasing and if you research on this subject you will realize that red mud contains a lot of caustic in it so it is pH is about 12 to 30. So you are stacking a material on the surface of the earth which is highly basic in nature clear. So this is the hazard associated with this. Now the question is how would you handle this how would you you know dispose it whatever these are the challenges which you are supposed to handle. Now look at the second situation which I have included over here they have several units in India which are operating and this is from Uthkul you know this should be I think from Belgaum I do not know whether you have seen this or not this is the refinery alumina refinery and when you drive from Bombay towards Kerala or Karnataka then on the way you will realize that there is a big stack of you know red mud and this is a national highway Mumbai highway you can see. So the handling disposal maintenance of these type of huge disposal facilities which have been created as a you know as a consequence of modern day civilization is a big challenge brainstorm your session to brainstorm and give the answers to the industry. This is the eastern part of the country from Uthkul which I have taken I do not know how many of you know this place in Orissa. So this is a unit where the process is being done and disposal is being done at several kilometers away. So piping, pumping of the red mud or the industrial byproducts which are coming out is a big issue. So designing of these retention ponds is a big question big challenge unfortunately not many people are aware of you know the practice of dealing with the waste which is chemically activated. Had it been soils 200 years, 500 years, thousands of years people have the experience of handling with the soils and making retention system. But when it comes to the chemically active systems how would you handle them, how would you use them, how would you create something out of this is a big question. Another example I thought I will show you is of again the Hindalko, well this is from the Renu court in the Mezapur district of UP. So look at this I mean these are the, so this is the Renu river and you know this is the belt where most of the thermal power plants a lot of mining is going on. And this is a huge plant where the alumina refinery is Renu court. And look at this the way the red mud is being disposed and now the question is how to tackle it in a scientific manner. And you should read about this accident which occurred sometime back, Ajika aluminum plant you know which happened in Hungary. So these are the you know slope stability issues which you should be dealing with as environmental geotechnology, geotechnologist. These are all soil, water, environment, interaction, examples, WCL coal mines, a lot of acid mine drains and drainage is taking place you know. If you see, zoom this system you will realize that a lot of mining is going on you know these are the extra deep mines or which WCL is trying to do. And this is where I work on the mining issues, geo-environmental issues related to mining operations. These are the extra large mines the diameter would be about 7 to 10 kilometers and they are trying to go up to several hundreds of meter deep in the ground to excavate the coal. So these type of problems you can realize now to see you know you can imagine that a large portion of the soil has been cut. So these slopes remain unstable most of the time you have to stabilize them. I am doing a project right now at WCL Vane Gaum project this is what is known as Vane Gaum. And I hope you can realize that if I tell you the intricacy of the things you know this is the river. So most of the mines are you know in the vicinity of the rivers alright. Look at this, this is the confluence of the mine for the rivers this is one river and this is another river and this is where the mines are located. So lot of discharge takes place when you excavate and you know that becomes a very critical issue that how would you do mining against excessive discharge. Remember these are simple slope stability problems but then they are having an issue which is associated with the environment. It could be seepage, it could be chemicals, it could be temperatures, it could be bacterial pathogenic and so on. So we are talking about different type of situations. Well these are the challenges which we have to face as a geotextile engineer in today's world. This is our landfill extremely close to IID campus this is the Devanar dumping landfill when you go towards VT from the eastern express highway you will realize that there is a huge land and when you are landing inside the Bombay city you know when the pilot announces crew stations, landing at stations. So that point if you start looking at down then you will realize you can see some part of the landfill quite clearly. So this is another issue where landfill fires took place in the recent past and the whole Bombay city had tough time you must have seen the photographs which were released by NASA about 2-3 years back you know it shows the magnanimous nature of you know how much the landfills are responsible for polluting the water bodies if the designs are not done properly. So what you are seeing over here is this is the Devanar dumping and look at the population the population is just right up to the brim of the landfill you know they are in fact living over there because they do not find the land. So this is the modern day civilization which we are so much proud of I hope you can realize look at the densely populated areas in the vicinity of the landfill and then there are water bodies streams of water which are getting polluted because of landfills, leachates or the gases which are coming out of it alright. So this gives you a good example of what type of interaction we are talking about. So I have talked about different sectors industrial processes and even the you know at municipal level also the type of pollution which is becoming a big threat to the modern day civilization mining, dredging, we will talk about all these sectors slowly and slowly. Exactly you were saying that you are working with WCL sectors in case of mines. So what are the actual problems they are facing can you please name some. All problems and problems and problems only this is nothing which is not a problem they are starting from site selection to dumping of the overburden to creation of the material for reclamation of the mines to stability of the mines to seepage in the mines to toxic water which is coming out of the mines we have to discharge it how to treat it how to put it back in the rivers to social issues, political issues, agricultural lands lost. So many things how to minimize the area where the stacking can be more and more higher that is what everybody wants then how to utilize this material for other purpose yeah so I think I can show you the lagoons also in fact in Bombay this is the guard copper lagoon you know have you ever seen a lagoon. So these are the aerators which are aerating yes mixing and aerating so that these water gets cleaned up. So these are the aerators which are installed over here and yeah sir is it possible to quantify the strength that is provided by the vegetation roots of it is it possible to quantify the strength quantify yeah of course yes lot of papers are there as a new subject all together so they do you will be surprised to know that the geotechnical engineers take out the roots and they find out the tensile strength of the roots also and they implement it in the models which they have done 3D models. So this is where the subject is all sorts of interactions are being modeled now in your softwares how the properties change over a period of time I mean I remember I had written a proposal where I wanted to see how roots migrate in the soil I wanted to capture everything electronically by using a set of sensors and then I wanted to relate it to the growth of the canopy of the tree somehow this project was not funded all this happens. So I wanted to study because see as I said a farmers will never study the mechanics of the problem beneath 200 to 300 centimeters all right maximum because that is the zone in which they are interested beyond that is our run so we have to understand how roots migrate is for me say is a tensile strength of soils and the roots migrate into it reinforcement of the soil because of secondary tertiary roots and so on so my perception of looking at the problem is different yeah yes so quantification has been done please read recent papers. Sir one more question is that that you said about the acid drainage by mining is it possible through non-mining activities like some construction of tunnels or something. So wherever you have pyrite or iron sulphide and when it gets exposed to the atmosphere oxygenated oxidized then sulphuric acid is going to get formed and how long will the effect last how long means now once the acid comes out and starts flowing in the water body you read about what is happening in the Assam most of the rivers are polluted people cannot drink water so these are the issues so these are the contemporary issues you should be aware of you know what is happening how would they do cultivation because if acids are present in the water this water cannot be used for vegetation yes please. So if we compare the strength of roots of plants will that be like comparable to our geomaterials geotextiles. Let me the biggest issue is without plant without plant without roots what is the strength of the material and if I grow them what is going to happen so an engineer always talks about cross and cons clear. So sometime back I said that roots can be used grass can be used to stabilize the slopes. Now if I want to quantify the whole thing I would like to see from initial condition how much the material has got upgraded or it has deteriorated you never know the roots might deteriorate the rocks also you must have seen sometimes the vegetation on the you know concrete creates cracks also. So this is where judiciously you have to understand the mechanism so maybe a very open ended answer to your question is that you have to observe what is happening and then you have to understand the whole mechanism. So that is why I say that most of these mechanism the process require lot of time of your life. Sir can we use all type of plants means for. No there are different types of varieties I mean you should read in I mean I am not a plant pathologist. Some are good for soil and some are not ground water depletion. I agree with you yes yes so that is a big subject what type of vegetation and weight of the vegetation itself is going to be a big problem. So suppose you are stabilizing the slopes and if you plant a mango tree over there is going to be societal. Recently I read in Punjab there was a problem related with ground water depletion due to paddy cultivation. Correct not paddy there are few trees which uptake lot of water particularly you can this is one there are different types of it. So this is where you have to sit down and you have to talk to the you know plant pathologist the guys who are experts in subjects particular subject. So this is what we do so like my laboratory we talk about the nutrition of the soils and within this nutrition on the soil what can be grown. Sometimes the nutrition can also be changed I can create a nutrition depending upon the requirement. That is where the science of the technology of the soils comes in the picture catering to the requirement of a project you create something alright so you have to do all this. If this subject intrigues you then read more and more on different types of varieties of plants. Yeah so another example of the question could be sometime back when I was dealing with a contaminated soil and we wanted to rectify it so I had recommended some varieties of the plants for phytoremediation. So phytoremediation is a very big subject in geotechnical engineering on which lot of people are working already. So what species of chemicals can be logged alright logged in the sense that once you grow these type of plants they have a uptake capacity and they will solve all these type of heavy metals concentration of chemicals and this chemical concentration cannot move from one place to another place passivation. So these are big subjects people like you should come forward and study them yes. Sir we have seen that soil interaction with heat chemical etcetera what about magnetic field. Yeah so it is less study but my student on Dr. Susha Lakshmi so her thesis if you see in the paper which she has published is the magnetic characterization of soils was published about 2 years back in ASTM go through that paper and I think our lab was the first to talk about the magnetic characterization of the soils and generalize the magnetization behavior of the soils. So we are trying to classify the soils based on their magnetic characteristics and why we are doing this because we want to understand the soil moisture content. So you might not have thought by this time that how critical the soil moisture content is and soil moisture content depends upon the magnetic characteristics of the soils.