Lecture 07 : Rock Properties & Testing-2

[Music] let me welcome all of you to the drilling and blasting direction this is the 2nd lecture on the rock properties and trying out where we can talk about in regards to the how the unique Rock residences will also be measured and how the they’re influencing the drilling operation whilst we’re undertaking it in a rock so like each classification allow us to retrospect what we now have studied up to now in our previous lecture we understood the force of the rock mass underneath the influence of compression anxiety and shear so now we have understood their measurement approach now we have understood how they’re influencing now we have additionally understood the distinctive experimental systems to measure the force of the rock so at this point we’re ready to categorize distinctive rocks in step with the rock strength and from there we are able to say it could be gentle rock it could be rough rock it usually is medium tough rock so from there we now allow us to see the opposite influencing parameters of the Rock houses and this classification our objective is to grasp the opposite influential bodily Rock residences like hardness elasticity plasticity aggressiveness texture structure traits of breakage and to realise the size approaches of these Rock properties so allow us to start with the first Rock property that is hardness so hardness is viewed to be the resistance of a surface layer to be penetrated by way of one more body of tougher consistency so that suggests say suppose we’re having a knife the Tyrael is sizzling how so much tough in opposition to that knife is regarded how conveniently the knife is basically scratching that material so clearly that is the hardness of that material against the knife so in rock additionally we remember it is a operate of the hardness and composition of its mineral grain the porosity measure of humidity so clearly a rock material is viewed sizzling if it’s not ready to be scratched by means of many of the other rock fabric so that’s regarded tough so scorching is the one Rock property and it has been observed most of the times if the rock material containing very hot grains okay in order that fabric indicates the better hardness and by and large the fabric fashioned below excessive temperature shows the high hardness with admire to the opposite rock material so the hardness of Rock is the mainly the style of resistance that have got to be overcome throughout the drilling when you consider that once the beat has penetrated the leisure of the operation is less difficult so the primary the rock layer if the beat is in a position to penetrate this one then the rest portion leisure grains may also be without problems sheared off or could also be quite simply crushed off so the penetration of the primary point first angular point is principal and that’s the depending on the hardness of this rock material so for this reason hardness is truly a very very principal parameter whilst we’re due to the fact the drilling operation the most fashionable experiment procedure of hardness is called mos scale hardness truly a hundred years back extra hair stable of this scale which is clearly a quantity scale from one to 10 one is the tulk and ten is the diamond okay so there are two three 4 five up to ten is there stuff less difficult to don’t forget this is known as that you may have something said the German cat feared an oriental cue into complete loss of life so T the German it Germans T is tulk G is gypsum a cat is calcite f is feldspar a is apatite o is orthoclase q is Squatch our tea is to pouch and see is corundum and D ultimate one D is diamond so this is a one to ten scale of hardness which is clearly a qualitative experiment which is sincerely a qualitative experiment of hardness of the fabric so let us realize this video which sincerely provide the small print of this this video is available in the you tube which you could download that video from there they are additionally probably the most reasons used to identify minerals is their hardness which means that how well they face up to being scratched with the aid of a harder mineral so what we’re gonna do is go via and show you the steps that we would take to exhibit hardness for the minerals that is talc that is listed as quantity one to your list with talc it is some of the softest minerals and for those who observe that even my fingernail will leave a scratch on it this is quantity two it can be known as to sell and it’s also an awfully smooth mineral and with a purpose to also exhibit that is referred to as calcite it is quantity three for your record this one we can are trying with it fingernail but it quite is too difficult for my fingernail to go away a scratch so for the next move we would are trying a penny which is made of copper and we are going to find that if we press tough ample you see it leaves the scratch all correct is going to be a bit of tougher than the calcite this time the penny will not be gonna scratch it but if we take the fluoride we will scratch the penny so you see you see the scratch sure I believe we see k k so that implies that floor proper is more difficult than the copper then we can additionally but we will to find anything that’s tougher than the floor correct if we use a blade after which a steel blade we are able to in reality then scratch the floor act so it takes them this is going to be tougher than the floor suggestions due to the fact that this the blade scratches ok we’re getting a bit bit more difficult that is called apatite this is quantity five on the list we’re gonna to find that the blade will even scratch it and this one’s a bit of bit harder to look the great blade will scratch it however it’s tougher it’s more difficult for me to scratch it with the blade so that’s when you consider that that is tougher than the fluorite that we scratched earlier than there was once slightly bit less difficult to scratch so we’re getting tougher every time that is number six that’s referred to as feldspar this time the place we Kurt we weren’t equipped to scratch the others with the blade this one shouldn’t be going to scratch with the blade if I pressed it even press it down I are not able to get it to scratch so that implies this is more difficult than the blade but when I take a bit of glass the feldspar can scratch the glass if that girl’s cutting it there so the feldspar is harder number seven it’s quartz and this one can also be going to be harder than the glass nevertheless it must scratch the glass somewhat bit easier given that it is more difficult let’s see if it does very most likely cuts through the glass much less difficult than the feldspar dia where we had quartz earlier than that is number eight that is topaz so as the numbers get greater we’re getting harder so now we will take the Topaz and see that it to prove that it is harder it will scratch this quartz but it surely’s a bit bit tougher to get them to scratch as we get tough more difficult and harder that’s one does not hmm okay are we seeing anything not fairly yeah and so we get more difficult than they there are more difficult and so we’re no longer gonna get as with ease as scratch as we did earlier than number eight again with the topaz quantity nine is known as corundum corundum is one of the hardest minerals that we’ve and we will see that if it does a pretty good job i am scratching the Topaz i am gonna take scratches right there k all proper as soon as once more 9 whisper finish them number 10 you can notice that I for those who see anything in your if we appear on the kit it can be gonna say now not within the kit for a quantity time number 10 is a diamond this occurs to be my in my ring the diamond is there we talked about in class that diamonds are the toughest diamond if I would get to the diamond to the brink of it it would scratch the corundum seeing that diamond once more is the toughest mineral that we have now aside from this most talent of hardness the surface hardness can be confirmed quantitatively through a couple of other assessments although these are and these aren’t normally the direct test some are the indicative checks also so one in all such assessments is called Smith rebound hammer this is the Smith rebound hammer different two forms of hammer can also be there but essentially the most usual one easties Smith rebound hammer the place a ball is dropped and it’s remount length is measured using the hammer so that is very very often used there are two varieties of Smith hammer available L type n type and most mainly for rock more often than not we use n kind of Smith hammer and velocity thermal facilities that it can be used for measuring the hardness of the skin hardness sincerely of the rock in any direction so let us see use of Smith hammer on this video to the straightforward instrument 10200 these are very discovered basically typical resistance in terms of strength [Applause] this transformation the Sosa rebound number that is get together as soon as again the quantity of samples discards the value one rebound the indicator has moved up to the number and that is why it’s referred to as rebound quantity so rebound number can be immediately correlated with the opposite mechanical properties also so clearly Smith hammer gives the skin hardness of the rock structure even when it is within the in situ and that is room and no rebound number sincerely dictating the hardness of the rock floor aside from that another hardness measuring methods are there like Brinell hardness etcetera although which you can read those matters from the textbook regular textbooks available for the rock properties so this is the drilling resistance we’re drilling resistance is is the system on the whole used to verify the illustration for example the situation of a constructing stone or wall some thing like that and here the drilling resistance is applied through measuring the with the aid of applied the miniature drilling on to the specimen hardness is also measured utilising the Rockwell scale it’s a hardness scale it is a hardness scale based on the indentation of the indenter indentation hardness of a material so essentially this is the indentation scan the place in this English scan hardness is depends on measuring the depth of penetration of an indenter below a massive load in comparison with the penetration made by way of a preload so in actual fact here the indenter is allowed to penetrate in the sample Indian tourism out to penetrate in the sample with a small load and with a colossal load ok so say first the initially a small load is given on to the ball indenter or cone indented diamond cone indenter so and on the equal indenter subsequently a massive load in a separate experiment cycle a enormous load is given to find out the penetration depth so utilizing this penetration depth this hardness is determined the place this a B C D these are constants are given depending on the for the rock rocks good scale relying on the burden and types of balls additionally k so these details are given utilising these small print the within the Rockwell scale the hardness of the surface hardness of the material may also be decided so let us detect one such video on hand within the into YouTube for measuring the rockwell hardness the rockwell hardness tailed scale see in this video we can exhibit how the rockwell hardness test works making use of a equipment wheel the basic concept of this scan approach is to measure the permanent depth of indentation of a hardened enter underneath a experiment force within the process variant scale see a rounded cone manufactured from diamond is used as an indenter in step 1 the diamond cone is pressed onto the test piece surface with a minor drive of 10 kilo pond’s the depth of indentation under this preliminary load is the reference factor in step 2 the scan drive is elevated via 100 and forty kilo pawns which is appearing because the most important force this means that an overall force of 150 kilo pond’s is now performing on the inventor and this force is held for a detailed time in step three the predominant force is eliminated again at the same time the minor force continues to be acting the permanent expand in depth of indentation ii is measured that is how the rockwell hardness is calculated rockwell hardness HRC is equal to zero.2 – everlasting depth of indentation e in millimeters instances 500 let’s take a look at how the scan is applied in practice the tester selects the conical diamond and enter and installs it in the trying out desktop [Music] then he picks up the gear wheel and places it on the aid desk after rotating the microscope lens to its vertical function he can modify his test piece as quickly because the focused snapshot will also be obvious on the reveal the surface of the test piece is in the proper top the scan can in cutting-edge testing machines the Rockwell hardness experiment is completely automated that’s why the Rockwell hardness test is used so more commonly in automatic creation lines that’s it the Rockwell hardness of our gear wheel is fifty five HRC this outcomes is displayed on the reveal [Music] so the subsequent property is elasticity elasticity for lots of the rocks that is basically giving an elastic fragile behavior which obeys the Hookes regulation and are destroyed when the pressure exceeds the limit of the pliancy so sincerely elasticity is basically we measure making use of the poisons ratio and as in the last class additionally we’ve got discussed the poisons ratio of lots of the rocks is varying between factor one to factor two five you already know the limit of individual stress is zero.5 lots of the cases we located the poisons ratio various between these two we will measure the poisons ratio whilst we are proper and we’re conducting our uniaxial compressive scan with the aid of providing a strain gauge at the site portion of the sample we can examine the poisons ratio otherwise if we are conducting the wave velocity elastic or beneath in seismic pace we’re engaging in the measuring of seismic wave speed P and s pace on the rock sample in those cases also we can we will not directly calculate the poisons coefficient utilizing using mechanical utilizing some physical relationship amongst them a plasticity a starts when the rock stress exceeds the limit of elasticity then plasticity plasticity comes and residual stresses are becoming most important when the plastic stage is there so plasticity is determined by the mineral composition of the rock and diminishes with an expand in the quads equipped feldspar and different rough meet Emma tree minerals nevertheless lots of the rock behaves more brittle nature than the ductile nature for this reason the plasticity limits are very restrained after the the second elastic it core across the elastic restrict cracks are developed and residual strengths are becoming no longer that so much massive abrasive ‘ti is one of the very very major parameters once we are seeing that the drilling section in view that Umbra Civet II in actual fact dictates the consumption of the drill steel via blunting the drill bits abrasiveness is the potential of the rock to put on away the contact floor of yet another body which is tougher so in rubbing of two bodies the abrasive material sincerely he wrote the a different body so the abrasive it is in actual fact very very essential it has been found that impressiveness raises with the hardness in order that instantly hardness is clearly dictating the abrasive ax T the second the rock fabric containing angular and rough mineral grains it displays more elasticity than the opposite material there are two long-established checks to be had for the abrasive ‘ti measurement one among that may be very very famous searcher abrasive a t-test an additional one is see magic as a prohibitive experiment the cause is that truly impulsivity is said with the content material of the quads or the silica content so equivalent compressibility essentially investigate the percentage of the silica whereas searcher abre civet II is an instantaneous pin experiment where the pin is scratched to search out the how much the pin tip material has misplaced his angularity so this is the reason that is such horrible accessibility test is very very standard for testing the abrasive ET so the checking out procedure is that it is a steel pin with a defined geometry that means it is having it’s having a forty five measure it is having a precise tip perspective and the metal is have a unique hardness it’s allowed to scratch over a rock sample as much as a distance of 1 centimeter beneath a static load of seven kg just about 7 kg 70 Newton so the sharpness misplaced within the tip is defined as the searcher aggressivity so truly this is a direct dimension of the Nativity applied let us notice this one so essentially this is the steel pin if I don’t forget that is more often than not showcase the attitude of 90 degree i will keep in touch it after staring at the literature so we realize the bluntness of the tip after scratching it after scratching it on a pattern of 1 centimeter length beneath a 7 kg load will take in this bluntness of the tip in a ocular microscope of 200 magnification so the searcher abrasive ax T is calculated using this formula where D is the gap not the diameter absolutely this is the space of flatness and sees the correction causes applied so this is sincerely giving us magnification of the that with the 10 is giving us the searcher Abra civet e of the material so that is a direct use of the Umbra symmetry of the fabric where the pin is subjected to under a abrasion and this action of the pin of 10 mm or 1 centimeter length needs to be applied inside a time span of 1 2nd so in actual fact this is the set up this is the mounted in most cases used for the Abra searcher Abra sweetie checking out nonetheless searcher Abra civet is also carefully associated with the drill rate index so that additionally can also be applied in different instances for the indirect dimension of the searcher Abra civet II so let us see in regards to the texture texture of a rock refers to the structure of the grains of the minerals that represent it the dimensions of the grain are a sign as good as they are safe porosity etcetera so the angular grains are extra difficult and smooth brains are extra rough so those are to be considered whilst we are undertaking the while we’re accomplishing the drilling operation on a rock the structural houses of the rock mass can also be major sister city bedding planes joints these are faults and their orientations are additionally very essential whilst the drilling is being carried out and ultrasonic trying out is carried out to know the P and S wave speed of the rock this essentially gives us the proposal concerning the concerning the compactness compactness of the rock throughout the rock mass and this also shows the strength of the rock moss clearly in different phrase you could say the ultrasonic trying out for the choosing the P and sa velocity of the rock is the only scan for which offers us the dynamic or gives us the indication over the dynamic property of the rock so sincerely these are also dictates how the vigor will be transferred from the explosive to the rock all these are relying on this ultrasonic rock homes so that is additionally very very most important whilst the dynamic failure is applied there are other properties additionally that are influencing the drilling and blasting operations nonetheless allow us to stop at this role the other rock homes it’s favored that you must learn from the textbooks on hand for this I strongly advocate the books of Jame no I strongly propose the books of dice for drilling this needs to be referred to your extra learn for your possess position thanks

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