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 speak about in regards to the how the different Rock residences may also be measured and how the they’re influencing the drilling operation whilst we are undertaking it in a rock so like every type allow us to retrospect what we’ve studied so far in our prior lecture we understood the strength of the rock mass under the impact of compression anxiety and shear so we have understood their size approach we now have understood how they’re influencing we have also understood the different experimental approaches to measure the strength of the rock so at this point we’re able to categorize distinctive rocks in step with the rock force and from there we will say it may be gentle rock it usually is difficult rock it can be medium rough rock so from there we now let us see the other influencing parameters of the Rock properties and this type our goal is to know the opposite influential physical Rock properties like hardness elasticity plasticity aggressiveness texture constitution characteristics of breakage and to appreciate the measurement methods of those Rock properties so allow us to begin with the primary Rock property that’s hardness so hardness is regarded to be the resistance of a surface layer to be penetrated by another physique of more difficult consistency so that implies say feel we’re having a knife the Tyrael is hot how a lot tough towards that knife is regarded how quite simply the knife is basically scratching that material so basically that’s the hardness of that fabric against the knife so in rock additionally we take into account it’s a operate of the hardness and composition of its mineral grain the porosity measure of humidity so sincerely a rock fabric is viewed hot if it’s not in a position to be scratched by means of most of the other rock material so that is regarded difficult so scorching is the one Rock property and it has been observed lots of the instances if the rock fabric containing very hot grains okay so that material suggests the better hardness and probably the material shaped underneath excessive temperature shows the high hardness with appreciate to the opposite rock material so the hardness of Rock is the principally the kind of resistance that have to be overcome for the duration of the drilling on account that as soon as the beat has penetrated the relaxation of the operation is easier so the first the rock layer if the beat is capable to penetrate this one then the rest element relaxation grains may also be without problems sheared off or may be without problems beaten off so the penetration of the primary factor first angular factor is foremost and that’s the relying on the hardness of this rock material so that is why hardness is basically an extraordinarily very foremost parameter at the same time we are in view that the drilling operation essentially the most widespread scan method of hardness is known as mos scale hardness essentially a hundred years back more hair stable of this scale which is essentially a quantity scale from one to 10 one is the tulk and ten is the diamond ok so there are two three 4 five as much as ten is there stuff less difficult to don’t forget that is referred to as that you would be able to have whatever said the German cat feared an oriental cue into whole dying 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 final one D is diamond so this can be a one to 10 scale of hardness which is basically a qualitative experiment which is truly a qualitative test of hardness of the material so let us notice this video which clearly provide the details of this this video is to be had within the you tube that you can down load that video from there they are also one of the most causes used to determine minerals is their hardness which means that how well they withstand being scratched by means of a tougher mineral so what we’re gonna do is go by means of and show you the steps that we would take to show hardness for the minerals that is talc this is listed as number one for your list with talc it’s some of the softest minerals and in the event you realize that even my fingernail will depart a scratch on it this is number two it can be called to promote and it is also an extraordinarily delicate mineral and so that you can also exhibit that is referred to as calcite it can be number three in your record this one we can are trying with it fingernail however it fairly is simply too tough for my fingernail to depart a scratch so for your next step we’d are trying a penny which is manufactured from copper and we will in finding that if we press difficult adequate you see it leaves the scratch all correct goes to be a little harder than the calcite this time the penny will not be gonna scratch it but if we take the fluoride we are able to scratch the penny so you see you see the scratch yes I suppose we see ok okay in order that means that floor correct is more difficult than the copper then we can additionally however we are able to in finding something that’s tougher than the ground correct if we use a blade and then a steel blade we will simply then scratch the floor act so it takes them this is going to be tougher than the ground suggestions because this the blade scratches ok we’re getting slightly bit harder that is known as apatite that is number 5 on the record we’re gonna find that the blade will also scratch it and this one’s just a little bit more difficult to look the best blade will scratch it however it’s more difficult it can be more difficult for me to scratch it with the blade so that is considering this is harder than the fluorite that we scratched earlier than there was once just a little bit easier to scratch so we’re getting tougher each time this is quantity six that is called feldspar this time where we Kurt we weren’t able to scratch the others with the blade this one just isn’t 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 suggests this is tougher than the blade but when I take a piece of glass the feldspar can scratch the glass if that lady’s cutting it there so the feldspar is harder number seven it’s quartz and this one can be going to be more difficult than the glass nevertheless it must scratch the glass a bit of bit less complicated on the grounds that it is tougher let’s see if it does very undoubtedly cuts by way of the glass a lot less complicated than the feldspar dia where we had quartz before this is number eight that is topaz in order the numbers get higher we’re getting tougher so now we’re going to take the Topaz and notice that it to show that it can be harder it’ll scratch this quartz nevertheless it’s a little bit harder to get them to scratch as we get tough more difficult and more difficult that’s one would not hmm k are we seeing whatever not particularly yeah and so we get tougher than they there are more difficult and so we’re now not gonna get as readily as scratch as we did earlier than quantity eight again with the topaz number 9 is called corundum corundum is one of the hardest minerals that we have and we will see that if it does a fantastic job i’m scratching the Topaz i’m gonna take scratches right there ok all proper as soon as once more 9 whisper end them number 10 you’ll be able to detect that I in the event you see anything in your if we seem on the kit it can be gonna say not within the kit for a number time number 10 is a diamond this happens to be my in my ring the diamond is there we talked about in school that diamonds are the toughest diamond if I could get to the diamond to the threshold of it it would scratch the corundum considering that diamond again is the hardest mineral that we now have apart from this most skill of hardness the outside hardness can also be demonstrated quantitatively by way of a couple of other assessments though these are and these should not always the direct test some are the indicative exams additionally so one in all such assessments is referred to as Smith rebound hammer this is the Smith rebound hammer other two varieties of hammer can also be there however probably the most normal one easties Smith rebound hammer where a ball is dropped and it’s remount length is measured utilizing the hammer so that is very very more often than not used there are two varieties of Smith hammer available L variety n variety and most most of the time for rock more commonly we use n style of Smith hammer and pace thermal facilities that it may be used for measuring the hardness of the skin hardness basically of the rock in any path so let us see use of Smith hammer on this video to the easy instrument 10200 these are very found clearly common resistance in terms of force [Applause] this modification the Sosa rebound quantity that is celebration once once more the number of samples discards the worth one rebound the indicator has moved up to the quantity and that’s why it’s called rebound quantity so rebound quantity may also be instantly correlated with the opposite mechanical houses also so basically Smith hammer offers the outside hardness of the rock structure even when it’s in the in situ and this is room and no rebound quantity sincerely dictating the hardness of the rock floor apart from that any other hardness measuring procedures are there like Brinell hardness etcetera though that you could learn these matters from the textbook ordinary textbooks to be had for the rock properties so that is the drilling resistance we’re drilling resistance is is the method ordinarily used to verify the instance for instance the condition of a building stone or wall some thing like that and here the drilling resistance is implemented by measuring the by carried out the miniature drilling on to the specimen hardness is also measured utilising the Rockwell scale it is a hardness scale it’s a hardness scale centered on the indentation of the indenter indentation hardness of a fabric so essentially this is the indentation test the place on this English scan hardness is is determined by measuring the depth of penetration of an indenter underneath a big load compared to the penetration made via a preload so truly here the indenter is allowed to penetrate in the pattern Indian tourism out to penetrate within the pattern with a small load and with a gigantic load ok so say first the at the start a small load is given on to the ball indenter or cone indented diamond cone indenter so and on the same indenter due to this fact a significant load in a separate test cycle a significant load is given to discover the penetration depth so utilising this penetration depth this hardness is decided the place this a B C D these are constants are given depending on the for the rock rocks well scale relying on the burden and types of balls also okay so these details are given making use of these small print the in the Rockwell scale the hardness of the outside hardness of the material can also be determined so allow us to realize one such video on hand in the into YouTube for measuring the rockwell hardness the rockwell hardness tailed scale see on this video we will show how the rockwell hardness test works utilizing a apparatus wheel the elemental suggestion of this experiment procedure is to measure the everlasting depth of indentation of a hardened enter under a experiment drive within the process variant scale see a rounded cone made from diamond is used as an indenter in step 1 the diamond cone is pressed onto the test piece floor with a minor drive of 10 kilo pond’s the depth of indentation underneath this preliminary load is the reference factor in step 2 the test drive is accelerated via 100 and forty kilo pawns which is appearing as the fundamental drive this means that an overall force of one hundred fifty kilo pond’s is now appearing on the inventor and this force is held for a specified time in step three the foremost drive is eliminated again even as the minor force remains to be performing the everlasting increase intensive of indentation ii is measured this is how the rockwell hardness is calculated rockwell hardness HRC is equal to 0.2 – permanent depth of indentation e in millimeters times 500 let’s take a seem at how the test is carried out in observe the tester selects the conical diamond and enter and installs it within 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 position he can regulate his test piece as soon because the centered photograph can also be noticeable on the screen the outside of the experiment piece is in the correct peak the experiment can begin in trendy trying out machines the Rockwell hardness experiment is thoroughly computerized that’s why the Rockwell hardness scan is used so as a rule in computerized production traces that is it the Rockwell hardness of our equipment wheel is fifty five HRC this effect is displayed on the screen [Music] so the following property is elasticity elasticity for many of the rocks this is sincerely giving an elastic fragile behavior which obeys the Hookes regulation and are destroyed when the pressure exceeds the limit of the elasticity so in actual fact elasticity is sincerely we measure using the poisons ratio and as in the last type additionally we’ve got discussed the poisons ratio of lots of the rocks is varying between point one to factor two 5 the restrict of man or woman stress is zero.5 lots of the cases we determined the poisons ratio varying between these two we can measure the poisons ratio even as we’re correct and we are undertaking our uniaxial compressive scan by means of providing a strain gauge on the web site component of the pattern we will determine the poisons ratio in any other case if we’re undertaking the wave speed elastic or beneath in seismic speed we’re conducting the measuring of seismic wave pace P and s velocity on the rock pattern in these circumstances also we can we are able to indirectly calculate the poisons coefficient utilising using mechanical utilizing some physical relationship amongst them a plasticity a starts offevolved when the rock stress exceeds the restrict of elasticity then plasticity plasticity comes and residual stresses are becoming most important when the plastic stage is there so plasticity depends upon the mineral composition of the rock and diminishes with an broaden in the quads competent feldspar and other difficult meet Emma tree minerals nevertheless lots of the rock behaves more brittle nature than the ductile nature that is why the plasticity limits are very confined after the the moment elastic it core across the elastic limit cracks are developed and residual strengths are becoming not that so much colossal abrasive ‘ti is among the very very principal parameters after we are because the drilling section in view that Umbra Civet II basically dictates the consumption of the drill steel via blunting the drill bits abrasiveness is the capacity of the rock to put on away the contact floor of a further physique which is more difficult so in rubbing of two our bodies the abrasive material truly he wrote the a different body so the abrasive it is in actual fact very very important it has been found that impressiveness raises with the hardness so that instantly hardness is essentially dictating the abrasive ax T the second the rock fabric containing angular and difficult mineral grains it displays extra elasticity than the opposite fabric there are two normal exams to be had for the abrasive ‘ti measurement one in every of that could be very very famous searcher abrasive a t-experiment another one is see magic as a prohibitive scan the intent is that in actual fact impulsivity is related with the content of the quads or the silica content so equivalent compressibility in actual fact check the percentage of the silica whereas searcher abre civet II is a right away pin test where the pin is scratched to find the how so much the pin tip material has misplaced his angularity so because of this this is such horrible accessibility experiment may be very very fashionable for checking out the abrasive ET so the checking out approach is that it’s a metal pin with a defined geometry that means it’s having it is having a 45 degree it is having a specified tip perspective and the metal is have a unique hardness it’s allowed to scratch over a rock sample up to a distance of 1 centimeter below a static load of seven kg practically 7 kg 70 Newton so the sharpness misplaced within the tip is defined because the searcher aggressivity so clearly this is an instantaneous dimension of the Nativity carried out let us notice this one so truly this is the metal pin if I don’t forget that is regularly show off the perspective of ninety measure i’ll communicate it after gazing the literature so we realize the bluntness of the tip after scratching it after scratching it on a sample of 1 centimeter length under 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 utilising this components the place D is the gap now not the diameter clearly that is the distance of flatness and sees the correction explanations utilized so that is basically giving us magnification of the that with the ten is giving us the searcher Abra civet e of the material so that is a direct use of the Umbra symmetry of the material where the pin is subjected to under a abrasion and this motion of the pin of 10 mm or 1 centimeter length must be applied inside a time span of one second so clearly that is the mounted this is the mounted almost always used for the Abra searcher Abra sweetie trying out nonetheless searcher Abra civet can also be carefully related with the drill cost index in order that also will also be carried out in one of a kind circumstances for the oblique size of the searcher Abra civet II so allow us to see in regards to the texture texture of a rock refers to the constitution of the grains of the minerals that constitute it the scale of the grain are a sign as well as they’re riskless porosity etcetera so the angular grains are extra hard and smooth brains are more hard so those are to be viewed whilst we’re accomplishing the even as we are carrying out the drilling operation on a rock the structural residences of the rock mass can also be principal sister city bedding planes joints these are faults and their orientations are also very major while the drilling is being implemented and ultrasonic trying out is applied to know the P and S wave velocity of the rock this clearly gives us the idea about the about the compactness compactness of the rock throughout the rock mass and this additionally shows the strength of the rock moss clearly in other phrase which you could say the ultrasonic testing for the opting for the P and sa pace of the rock is the only scan for which gives us the dynamic or gives us the indication over the dynamic property of the rock so basically these are additionally dictates how the vigor shall be transferred from the explosive to the rock all these are relying on this ultrasonic rock residences so this is additionally very very fundamental while the dynamic failure is implemented there are different properties also which might be influencing the drilling and blasting operations however let us stop at this role the opposite rock houses it is preferred that you just must learn from the textbooks on hand for this I strongly suggest the books of Jame no I strongly advise the books of cube for drilling this needs to be referred to your further learn for your own location thanks

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