Lecture 07 : Rock Properties & Testing-2

[Music] let me welcome all of you to the drilling and blasting direction that is the 2d lecture on the rock properties and checking out where we can discuss about the how the exclusive Rock residences can be measured and the way the they’re influencing the drilling operation even as we are undertaking it in a rock so like each type let us retrospect what we’ve studied thus far in our previous lecture we understood the strength of the rock mass below the influence of compression anxiety and shear so now we have understood their size approach we have now understood how they’re influencing we have now additionally understood the different experimental approaches to measure the strength of the rock so at this factor we are capable to categorize different rocks in line with the rock force and from there we are able to say it usually is tender rock it can be rough rock it may be medium tough rock so from there we now let us see the opposite influencing parameters of the Rock residences and this type our goal is to grasp the other influential bodily Rock residences like hardness elasticity plasticity aggressiveness texture structure traits of breakage and to fully grasp the size methods of these Rock homes so let us begin 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 a further body of tougher consistency so that means say think we are having a knife the Tyrael is sizzling how a lot tough towards that knife is viewed how without problems the knife is sincerely scratching that fabric so clearly that is the hardness of that material towards the knife so in rock additionally we don’t forget it is a operate of the hardness and composition of its mineral grain the porosity degree of humidity so in actual fact a rock fabric is viewed sizzling if it is not competent to be scratched via most of the other rock material so that is viewed difficult so scorching is the one Rock property and it has been observed most of the instances if the rock fabric containing very hot grains okay so that fabric shows the higher hardness and often the material fashioned beneath high temperature suggests the excessive hardness with appreciate to the opposite rock fabric so the hardness of Rock is the mainly the variety of resistance that ought to be overcome throughout the drilling considering that as soon as the beat has penetrated the rest of the operation is easier so the first the rock layer if the beat is in a position to penetrate this one then the rest element leisure grains may also be readily sheared off or could also be with no trouble overwhelmed off so the penetration of the primary factor first angular point is major and that’s the relying on the hardness of this rock material so this is why hardness is truly an extraordinarily very major parameter while we’re for the reason that the drilling operation essentially the most general experiment method of hardness is called mos scale hardness essentially a hundred years again extra hair steady of this scale which is sincerely a quantity scale from one to 10 one is the tulk and ten is the diamond k so there are two three 4 5 as much as ten is there stuff less difficult to consider that is known as you could have some thing said the German cat feared an oriental cue into entire demise 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 can be a one to ten scale of hardness which is in actual fact a qualitative experiment which is essentially a qualitative test of hardness of the material so allow us to observe this video which basically give you the important points of this this video is on hand within the you tube that you would be able to down load that video from there they’re also one of the crucial factors used to establish minerals is their hardness which means how good they withstand being scratched by means of a more difficult mineral so what we’re gonna do is go by means of and exhibit you the steps that we might take to show hardness for the minerals this is talc this is listed as quantity one for your record with talc it’s one of the softest minerals and if you discover that even my fingernail will go away a scratch on it this is quantity two it can be referred to as to promote and additionally it is an awfully delicate mineral and so we can additionally show that is known as calcite it’s number three on your record this one we can are trying with it fingernail nevertheless it fairly is just too rough for my fingernail to leave a scratch so for the next move we’d are attempting a penny which is made from copper and we will in finding that if we press rough enough you see it leaves the scratch all proper is going to be slightly more difficult than the calcite this time the penny is just not gonna scratch it but if we take the fluoride we will scratch the penny so you see you see the scratch sure I suppose we see ok okay so that means that ground right is more difficult than the copper then we can additionally however we are able to to find anything that’s tougher than the ground correct if we use a blade after which a steel blade we are able to truly then scratch the ground act so it takes them that is going to be harder than the ground ideas due to the fact that this the blade scratches okay we’re getting a bit of bit more difficult this is called apatite that is number five on the record we’re gonna find that the blade will even scratch it and this one’s a bit of bit more difficult to see the first-class blade will scratch it but it surely’s tougher it can be tougher for me to scratch it with the blade so that is considering that is harder than the fluorite that we scratched before there was once a little bit less complicated to scratch so we’re getting more difficult at any time when this is quantity six that’s known as feldspar this time the place we Kurt we weren’t in a position 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 can’t get it to scratch so that means that is tougher than the blade but if I take a piece of glass the feldspar can scratch the glass if that lady’s cutting it there so the feldspar is more difficult quantity seven it is quartz and this one can be going to be harder than the glass but it surely should scratch the glass a little bit less difficult considering that it is more difficult let’s see if it does very surely cuts via the glass a lot less difficult than the feldspar dia where we had quartz before that is quantity eight that is topaz in order the numbers get greater we’re getting more difficult so now we will take the Topaz and spot that it to prove that it is harder it will scratch this quartz however it’s slightly bit harder to get them to scratch as we get tough tougher and harder that is one would not hmm k are we seeing some thing now not really yeah and so we get tougher than they there are harder and so we’re no longer gonna get as quite simply as scratch as we did earlier than quantity eight once more with the topaz number 9 is called corundum corundum is among the hardest minerals that we have now and we will see that if it does a superior job i’m scratching the Topaz i am gonna take scratches right there ok all right as soon as again 9 whisper finish them quantity 10 you can notice that I for those who see some thing for your if we look at the kit it’s gonna say not in the kit for a number time quantity 10 is a diamond this occurs to be my in my ring the diamond is there we pointed out in class that diamonds are the hardest diamond if I might get to the diamond to the threshold of it it would scratch the corundum for the reason that diamond again is the toughest mineral that we’ve apart from this most skill of hardness the outside hardness may also be demonstrated quantitatively through a couple of different assessments though those are and these usually are not at all times the direct experiment some are the indicative assessments additionally so one among such assessments is called Smith rebound hammer that is the Smith rebound hammer different two types of hammer is also there but essentially the most fashioned one easties Smith rebound hammer where a ball is dropped and it can be remount size is measured using the hammer so this is very very most commonly used there are two forms of Smith hammer available L kind n type and most almost always for rock customarily we use n form of Smith hammer and velocity thermal services that it may be used for measuring the hardness of the skin hardness sincerely of the rock in any course so allow us to see use of Smith hammer in this video to the easy instrument 10200 these are very observed clearly normal resistance in terms of strength [Applause] this variation the Sosa rebound number that’s occasion as soon as once more the number of samples discards the worth one rebound the indicator has moved up to the number and that’s why it’s referred to as rebound number so rebound number will also be immediately correlated with the opposite mechanical residences also so truly Smith hammer gives the surface hardness of the rock structure even when it’s within the in situ and that is room and no rebound quantity essentially dictating the hardness of the rock floor aside from that some other hardness measuring strategies are there like Brinell hardness etcetera although you can read these matters from the textbook common textbooks on hand for the rock residences so this is the drilling resistance we’re drilling resistance is is the method typically used to assess the illustration for example the of a constructing stone or wall some thing like that and here the drilling resistance is implemented via measuring the with the aid of carried out the miniature drilling on to the specimen hardness can be measured utilizing the Rockwell scale it’s a hardness scale it’s a hardness scale centered on the indentation of the indenter indentation hardness of a fabric so basically this is the indentation test where on this English test hardness is depends upon measuring the depth of penetration of an indenter beneath a massive load in comparison with the penetration made through 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 giant 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 identical indenter therefore a giant load in a separate experiment cycle a significant load is given to find out the penetration depth so making use of 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 depending on the weight and types of balls also ok so these details are given using these important points the within the Rockwell scale the hardness of the surface hardness of the material can be decided so let us notice one such video to be had within the into YouTube for measuring the rockwell hardness the rockwell hardness tailed scale see on this video we will be able to exhibit how the rockwell hardness test works using a gear wheel the basic inspiration of this scan procedure is to measure the permanent depth of indentation of a hardened enter below a test force in the process variant scale see a rounded cone fabricated from diamond is used as an indenter in step 1 the diamond cone is pressed onto the experiment piece surface with a minor force of 10 kilo pond’s the depth of indentation underneath this preliminary load is the reference point in step 2 the experiment force is extended by using a hundred and forty kilo pawns which is performing as the primary drive because of this an overall force of a hundred and fifty kilo pond’s is now acting on the inventor and this drive is held for a certain time in step three the predominant drive is removed again whilst the minor force continues to be appearing the everlasting increase intensive of indentation ii is measured this is how the rockwell hardness is calculated rockwell hardness HRC is the same as 0.2 – permanent depth of indentation e in millimeters times 500 let’s take a look at how the scan is implemented in follow the tester selects the conical diamond and enter and installs it within the checking out machine [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 adjust his experiment piece as quickly because the centered photograph will also be seen on the screen the surface of the scan piece is in the proper peak the experiment can begin in ultra-modern trying out machines the Rockwell hardness experiment is absolutely automated that is why the Rockwell hardness scan is used so in general in computerized creation traces that’s it the Rockwell hardness of our equipment wheel is 55 HRC this outcomes is displayed on the screen [Music] so the following property is elasticity elasticity for most of the rocks this is clearly giving an elastic fragile conduct which obeys the Hookes law and are destroyed when the pressure exceeds the restrict of the pliability so clearly elasticity is essentially we measure utilizing the poisons ratio and as within the last classification also we have discussed the poisons ratio of lots of the rocks is various between point one to factor two five you already know the limit of character stress is 0.5 most of the instances we found the poisons ratio various between these two we will measure the poisons ratio at the same time we are correct and we’re carrying out our uniaxial compressive experiment by providing a strain gauge on the website section of the sample we will determine the poisons ratio otherwise if we’re undertaking the wave pace elastic or below in seismic speed we are conducting the measuring of seismic wave velocity P and s speed on the rock sample in those instances also we can we can not directly calculate the poisons coefficient using utilizing mechanical making use of some bodily relationship amongst them a plasticity a starts when the rock stress exceeds the limit of elasticity then plasticity plasticity comes and residual stresses are fitting essential when the plastic stage is there so plasticity depends upon the mineral composition of the rock and diminishes with an expand within the quads ready feldspar and other hard meet Emma tree minerals nevertheless most of the rock behaves more brittle nature than the ductile nature this is why the plasticity limits are very constrained after the the moment elastic it core across the elastic limit cracks are developed and residual strengths are fitting not that much big abrasive ‘ti is one of the very very foremost parameters when we are since the drilling phase on the grounds that Umbra Civet II truly dictates the consumption of the drill metal with the aid of blunting the drill bits abrasiveness is the capability of the rock to put on away the contact surface of a different physique which is harder so in rubbing of two bodies the abrasive material clearly he wrote the another body so the abrasive it is essentially very very most important it has been determined that impressiveness increases with the hardness in order that directly hardness is essentially dictating the abrasive ax T the moment the rock fabric containing angular and rough mineral grains it exhibits more elasticity than the other material there are two customary exams on hand for the abrasive ‘ti size considered one of that could be very very noted searcher abrasive a t-scan another one is see magic as a prohibitive experiment the cause is that truly impulsivity is expounded with the content of the quads or the silica content material so similar compressibility in actual fact determine the percent of the silica whereas searcher abre civet II is a direct pin scan the place the pin is scratched to search out the how so much the pin tip fabric has lost his angularity so this is why that is such horrible accessibility experiment is very very general for trying out the abrasive ET so the trying out procedure is that it is a metal pin with a defined geometry that suggests it’s having it’s having a 45 degree it’s having a specified tip perspective and the steel is have a precise hardness it is allowed to scratch over a rock pattern as much as a distance of 1 centimeter beneath a static load of seven kg just about 7 kg 70 Newton so the sharpness lost in the tip is outlined as the searcher aggressivity so clearly that is a right away size of the Nativity carried out allow us to realize this one so truly this is the metal pin if I take into account this is commonly show off the angle of 90 measure i will keep in touch it after staring at the literature so we observe the bluntness of the tip after scratching it after scratching it on a pattern of 1 centimeter length beneath a 7 kg load will soak up this bluntness of the tip in a ocular microscope of 200 magnification so the searcher abrasive ax T is calculated making use of this system where D is the gap no longer the diameter virtually that is the space of flatness and sees the correction motives 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 this is an immediate use of the Umbra symmetry of the material where the pin is subjected to beneath a abrasion and this movement of the pin of 10 mm or 1 centimeter size must be carried out inside a time span of one second so sincerely that is the established that is the mounted typically used for the Abra searcher Abra sweetie testing nonetheless searcher Abra civet can be intently associated with the drill expense index in order that also can also be applied in specific circumstances for the indirect dimension of the searcher Abra civet II so let us see concerning the texture texture of a rock refers to the structure of the grains of the minerals that represent it the size of the grain are an indication as well as they are risk-free porosity etcetera so the angular grains are extra hard and soft brains are more tough so these are to be regarded even as we’re carrying out the while we are engaging in the drilling operation on a rock the structural homes of the rock mass can be predominant sister metropolis bedding planes joints these are faults and their orientations are also very important while the drilling is being carried out and ultrasonic trying out is carried out to grasp the P and S wave velocity of the rock this basically offers us the inspiration concerning the about the compactness compactness of the rock throughout the rock mass and this also suggests the strength of the rock moss truly in different phrase that you may say the ultrasonic trying out for the picking out the P and sa speed of the rock is the one scan for which offers us the dynamic or gives us the indication over the dynamic property of the rock so truly these are additionally dictates how the vigour will be transferred from the explosive to the rock all these are relying on this ultrasonic rock residences so this is additionally very very principal while the dynamic failure is implemented there are different homes additionally that are influencing the drilling and blasting operations nevertheless allow us to stop at this function the opposite rock residences it’s desired that you just should learn from the textbooks to be had for this I strongly propose the books of Jame no I strongly endorse the books of dice for drilling this must be referred on your extra gain knowledge of in your possess situation thanks

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