Lecture 07 : Rock Properties & Testing-2

[Music] let me welcome all of you to the drilling and blasting direction that is the second lecture on the rock homes and testing where we will be able to discuss concerning the how the specific Rock properties can also be measured and how the they’re influencing the drilling operation whilst we’re conducting it in a rock so like each category let us retrospect what we’ve got studied so far in our prior lecture we understood the force of the rock mass under the have an impact on of compression anxiety and shear so now we have understood their measurement approach we have now understood how they’re influencing we now have also understood the unique experimental systems to measure the force of the rock so at this point we are equipped to categorize distinct rocks in line with the rock strength and from there we can say it usually is delicate rock it usually is hard rock it may be medium difficult rock so from there we now allow us to see the other influencing parameters of the Rock homes and this class our goal is to know the opposite influential bodily Rock houses like hardness elasticity plasticity aggressiveness texture structure characteristics of breakage and to appreciate the size approaches of these Rock homes so allow us to begin with the first Rock property that is hardness so hardness is regarded to be the resistance of a surface layer to be penetrated via a different body of tougher consistency so that suggests say consider we’re having a knife the Tyrael is hot how much tough against that knife is viewed how easily the knife is basically scratching that material so truly that’s the hardness of that fabric in opposition to the knife so in rock also we consider it’s a function of the hardness and composition of its mineral grain the porosity measure of humidity so essentially a rock fabric is considered hot if it is not ready to be scratched via many of the other rock material so that is regarded rough so sizzling is the one Rock property and it has been located lots of the times if the rock fabric containing very sizzling grains k so that material suggests the greater hardness and traditionally the fabric shaped under high temperature shows the excessive hardness with respect to the other rock material so the hardness of Rock is the mainly the variety of resistance that have got to be overcome during the drilling in view that once the beat has penetrated the rest of the operation is easier so the primary the rock layer if the beat is competent to penetrate this one then the leisure portion rest grains will also be comfortably sheared off or could also be easily crushed off so the penetration of the first factor first angular factor is predominant and that is the depending on the hardness of this rock material so this is the reason hardness is truly an extraordinarily very major parameter while we are considering that the drilling operation probably the most popular scan process of hardness is referred to as mos scale hardness sincerely one hundred years back extra hair stable of this scale which is sincerely a number scale from one to ten one is the tulk and ten is the diamond ok so there are two three 4 five up to ten is there stuff less complicated to remember that is known as that you could have some thing said the German cat feared an oriental cue into entire 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 notice is corundum and D final one D is diamond so this can be a one to ten scale of hardness which is sincerely a qualitative test which is sincerely a qualitative test of hardness of the fabric so allow us to become aware of this video which clearly provide the details of this this video is to be had in the you tube that you can download that video from there they’re additionally probably the most causes used to determine minerals is their hardness because of this how well they resist being scratched by using a more difficult mineral so what we’re gonna do is go via and show you the steps that we might take to exhibit hardness for the minerals this is talc this is listed as quantity one in your record with talc it’s one of the most softest minerals and should you notice that even my fingernail will go away a scratch on it this is quantity two it’s called to promote and additionally it is an awfully gentle mineral and in order to also show that is known as calcite it’s number three to your record this one we will are attempting with it fingernail but it surely quite is too tough for my fingernail to leave a scratch so for your next step we’d try a penny which is made of copper and we will find that if we press difficult enough you see it leaves the scratch all right is going to be a bit of more difficult than the calcite this time the penny is just not gonna scratch it but if we take the fluoride we can scratch the penny so that you see you see the scratch sure I feel we see k ok so that means that flooring proper is harder than the copper then we will additionally however we are able to in finding some thing that is more difficult than the floor proper if we use a blade and then a steel blade we will surely then scratch the floor act so it takes them that is going to be more difficult than the floor ideas on account that this the blade scratches okay we’re getting just a little bit harder that is known as apatite this is quantity five on the record we’re gonna to find that the blade will even scratch it and this one’s slightly bit tougher to see the high-quality blade will scratch it but it surely’s harder it’s tougher for me to scratch it with the blade so that is considering this is harder than the fluorite that we scratched before there was once just a little bit less complicated to scratch so we’re getting tougher whenever this is quantity six that’s known as feldspar this time where we Kurt we weren’t capable to scratch the others with the blade this one will not be going to scratch with the blade if I pressed it even press it down I can’t get it to scratch so that suggests this is tougher than the blade but if I take a bit of glass the feldspar can scratch the glass if that woman’s chopping it there so the feldspar is more difficult number seven it’s quartz and this one can also be going to be harder than the glass however it should scratch the glass a little bit less difficult considering that it is more difficult let’s have a look at if it does very without doubt cuts through the glass a lot easier than the feldspar dia the place we had quartz before this is quantity eight that is topaz in order the numbers get greater we’re getting tougher so now we’ll take the Topaz and notice that it to show that it can be more difficult it will scratch this quartz but it surely’s slightly bit tougher to get them to scratch as we get hard tougher and more difficult that is one would not hmm ok are we seeing some thing now not quite yeah and so we get tougher than they there are tougher and so we’re now not gonna get as without difficulty as scratch as we did earlier than quantity eight once more with the topaz number 9 is referred to as corundum corundum is without doubt one of the hardest minerals that we’ve got and we’ll see that if it does a superior job i am scratching the Topaz i am gonna take scratches correct there ok all proper as soon as again 9 whisper finish them number 10 you’ll be able to discover that I should you see some thing for your if we seem on the kit it can be gonna say no longer in the kit for a quantity time number 10 is a diamond this occurs to be my in my ring the diamond is there we pointed out at school that diamonds are the hardest diamond if I would get to the diamond to the edge of it it would scratch the corundum in view that diamond again is the toughest mineral that we have now apart from this most talent of hardness the outside hardness may also be tested quantitatively by way of a couple of different exams though these are and these aren’t continually the direct scan some are the indicative exams also so one of such assessments is referred to as Smith rebound hammer this is the Smith rebound hammer different two forms of hammer is also there however the most normal one easties Smith rebound hammer where a ball is dropped and it can be remount size is measured making use of the hammer so this is very very ordinarily used there are two forms of Smith hammer available L variety n style and most most often for rock most often we use n variety of Smith hammer and velocity thermal facilities that it can be used for measuring the hardness of the outside hardness truly of the rock in any direction so allow us to see use of Smith hammer on this video to the straightforward instrument 10200 these are very discovered essentially regular resistance in terms of strength [Applause] this modification the Sosa rebound number that is celebration once again the number of samples discards the worth one rebound the indicator has moved as much as the number and that’s why it is known as rebound quantity so rebound number will also be immediately correlated with the opposite mechanical homes additionally so in actual fact Smith hammer offers 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 every other hardness measuring systems are there like Brinell hardness etcetera although you could read those things from the textbook general textbooks on hand for the rock residences so this is the drilling resistance we’re drilling resistance is is the procedure by and large used to check the example for instance the situation of a constructing stone or wall whatever like that and here the drilling resistance is carried out by way of measuring the by using applied the miniature drilling on to the specimen hardness can be measured utilising the Rockwell scale it is a hardness scale it is a hardness scale established on the indentation of the indenter indentation hardness of a material so clearly this is the indentation test the place in this English test hardness is depends on measuring the depth of penetration of an indenter underneath a huge load in comparison with the penetration made by means of a preload so sincerely here the indenter is allowed to penetrate in the sample Indian tourism out to penetrate in the pattern with a small load and with a tremendous load k so say first the originally 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 gigantic load in a separate test cycle a enormous load is given to discover the penetration depth so utilising this penetration depth this hardness is determined where 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 additionally okay so these small print are given using these important points the in the Rockwell scale the hardness of the outside hardness of the fabric can be determined so allow us to realize one such video available within the into YouTube for measuring the rockwell hardness the rockwell hardness tailed scale see on this video we can show how the rockwell hardness scan works making use of a equipment wheel the fundamental thought of this scan approach is to measure the everlasting depth of indentation of a hardened enter under a scan drive in the procedure variant scale see a rounded cone manufactured from diamond is used as an indenter in step 1 the diamond cone is pressed onto the scan piece floor 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 force is extended by way of a hundred and forty kilo pawns which is appearing as the essential force this means that an total force of 150 kilo pond’s is now acting on the inventor and this drive is held for a distinctive time in step three the fundamental force is eliminated again whilst the minor drive is still appearing the everlasting broaden in depth of indentation ii is measured that is how the rockwell hardness is calculated rockwell hardness HRC is equal to zero.2 – permanent depth of indentation e in millimeters times 500 let’s take a look at how the scan is carried out in observe the tester selects the conical diamond and enter and installs it in the trying out machine [Music] then he picks up the equipment wheel and places it on the support desk after rotating the microscope lens to its vertical function he can regulate his test piece as quickly as the targeted snapshot may also be visible on the display the surface of the experiment piece is in the right height the experiment can start in latest checking out machines the Rockwell hardness experiment is totally computerized that is why the Rockwell hardness test is used so commonly in automated construction strains that’s it the Rockwell hardness of our apparatus wheel is 55 HRC this effect is displayed on the screen [Music] so the subsequent property is elasticity elasticity for lots of the rocks this is in actual fact giving an elastic fragile conduct which obeys the Hookes legislation and are destroyed when the stress exceeds the restrict of the pliancy so sincerely elasticity is in actual fact we measure using the poisons ratio and as within the last class also we’ve mentioned the poisons ratio of most of the rocks is varying between factor one to point two 5 you know the limit of character stress is 0.5 many of the cases we located the poisons ratio varying between these two we can measure the poisons ratio at the same time we’re right and we’re engaging in our uniaxial compressive scan by supplying a pressure gauge at the web site component of the pattern we will investigate the poisons ratio otherwise if we are carrying out the wave velocity elastic or below in seismic pace we are carrying out the measuring of seismic wave pace P and s pace on the rock pattern in these cases also we will we can not directly calculate the poisons coefficient utilizing using mechanical utilising 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 fitting most important when the plastic stage is there so plasticity depends upon the mineral composition of the rock and diminishes with an develop in the quads competent feldspar and different rough meet Emma tree minerals nonetheless many of the rock behaves more brittle nature than the ductile nature that is why the plasticity limits are very limited after the the moment elastic it core across the elastic limit cracks are developed and residual strengths are becoming now not that so much large abrasive ‘ti is among the very very foremost parameters once we are seeing that the drilling part because Umbra Civet II in actual fact dictates the consumption of the drill steel through blunting the drill bits abrasiveness is the potential of the rock to put on away the contact surface of yet another body which is more difficult so in rubbing of two our bodies the abrasive fabric truly he wrote the a further physique so the abrasive it’s essentially very very important it has been determined that impressiveness increases with the hardness so that directly hardness is truly dictating the abrasive ax T the moment the rock material containing angular and hard mineral grains it displays extra elasticity than the other material there are two common checks to be had for the abrasive ‘ti measurement considered one of that may be very very noted searcher abrasive a t-experiment an additional one is see magic as a prohibitive experiment the motive is that truly impulsivity is related with the content of the quads or the silica content so an identical compressibility clearly verify 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 much the pin tip material has lost his angularity so this is why this is such terrible accessibility test could be very very fashionable for testing the abrasive ET so the testing approach is that it’s a steel pin with an outlined geometry that means it is having it is having a forty five degree it is having a precise tip angle and the steel is have a particular hardness it’s allowed to scratch over a rock pattern as much as a distance of 1 centimeter below a static load of seven kg close to 7 kg 70 Newton so the sharpness lost in the tip is defined as the searcher aggressivity so basically this is an instantaneous dimension of the Nativity applied allow us to discover this one so truly that is the metal pin if I don’t forget this is probably exhibit the attitude of 90 measure i will keep up a correspondence it after staring at the literature so we detect the bluntness of the tip after scratching it after scratching it on a sample 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 utilising this formulation where D is the distance not the diameter honestly that is the gap of flatness and sees the correction explanations applied so this is in actual fact giving us magnification of the that with the 10 is giving us the searcher Abra civet e of the fabric so that is a right away use of the Umbra symmetry of the material the place the pin is subjected to below a abrasion and this action of the pin of 10 mm or 1 centimeter length must be applied inside a time span of one 2nd so basically that is the installed that is the hooked up usually used for the Abra searcher Abra sweetie trying out nevertheless searcher Abra civet is also intently associated with the drill rate index so that additionally will also be carried out in distinctive instances for the indirect size of the searcher Abra civet II so let us see in regards to the texture texture of a rock refers back to the structure of the grains of the minerals that represent it the size of the grain are an indication as well as they’re dependable porosity etcetera so the angular grains are more difficult and delicate brains are more hard so those are to be regarded at the same time we’re engaging in the even as we are carrying out the drilling operation on a rock the structural residences of the rock mass can be major sister city bedding planes joints these are faults and their orientations are also very fundamental even as the drilling is being implemented and ultrasonic trying out is carried out to understand the P and S wave speed of the rock this essentially gives us the thought concerning the in regards to the compactness compactness of the rock throughout the rock mass and this additionally suggests the strength of the rock moss basically in different phrase which you could say the ultrasonic checking out for the picking the P and sa speed of the rock is the only experiment for which offers us the dynamic or gives us the indication over the dynamic property of the rock so sincerely these are additionally dictates how the power will probably be transferred from the explosive to the rock all these are relying on this ultrasonic rock houses so that is additionally very very important even as the dynamic failure is applied there are different homes also which are influencing the drilling and blasting operations nonetheless let us stop at this function the opposite rock properties it is preferred that you should learn from the textbooks available for this I strongly propose the books of Jame no I strongly recommend the books of cube for drilling this needs to be referred on your additional learn to your possess situation thanks

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