CE 326 Mod 12.9b Triaxial Shear Test

CE 326 webcast on triaxial shear testing; Section 11.9

[@simonnguyen3606]

whoever gave this a thumbs down must be CRAZY! Being able to see a visual representation of what is happening on the graph while the test is being conducted is what makes this such an effective video. I look forward to viewing your other videos CHEERS!

[@alideep9656]

I live where the Triaxial stress is so expensive and the university never turned the device on or fully explain how things go during the test, I can't thank you enough for this outstanding explanation.

[@robertplautz9722]

it is hard to find videos of this quality: clear sharp narration, easy-to-understand, detailed explanation, amazing graphical (visual) presentation. thank you so much!

[@m3talh3ad18]

Thank you so much for your simplified and on the point explanations. I tried a lot of text books but everything was a bit complicated, for me. Your voice is clear and slides are well made.👍🏾

[@emmerydickinson8302]

A simplify yet comprehensive explanation about triaxial tests. Thanks a lot for a helpful video

[@rafiullahqallander]

Dear Professor Kitch, Thank you so much for such incredible explanation; you saved my life :)

[@taladiv3415]

Thank you yet again Prof. Kitch for using your talents to help unlucky students make sense of all the letter and figure salad !

[@muhammedajmal715]

It was an excellent presentation with to the point explanation with figures. Easy to understand the concept. Thank u soo much professor

[@user-ww5cm6zw2w]

Thanks for your video! Its clearly observed misbeliefs of foreign geotechnical engineering based on outdated Therzagi's theory. Very helpful for my students.

[@AroundRavikant]

extremely thankful to u for this video... i was confused from many days about this topic.

[@gh5030]

That’s what happens when we mix the hight knowledge and super teaching ability, very very useful, much better than my text book.. thank you so much

[@meaghanmacquarrie3755]

Thank you for this video. You have helped me develop a better understand on concepts I have struggled to learn. This is one of the best videos I have come across. I especially liked the corresponding mohr-circle diagram to triaxial type test! Thank you!!!

[@debangsu3181]

SUCH A SIMPLE AND TO THE POINT EXPLANATION OF CU,UU,CD TESTS

[@39shobhit]

very nice and effective presentation .... all the concept that you have told can be easily understood ......thank you for this great work ....

[@mounika501]

Outstanding explaintion I'm really happy with thus vedio nd I learn very much about this topic

[@n4tsumi]

Really helpful for confused engineering student like me! thank you!

[@zs6511]

Best video for triaxial shear test.

[@VikashKumar-vl4hv]

excellent video, one of the best study tutorial video i have gone through. thanks a lot sir

[@shahriarislam7134]

Wishing to see more of these helpful videos

[@rhushitparmar5939]

Thank you so much. It's very conceptual and cleared my all doubts.

[@SauravKumar-ic4ly]

Thank you so much for this video, such an amazing way of explanation.

[@gildanibarcentti5954]

Excellent explanation! Love your ending :)

[@omkardhamane269]

Thank you so much for this video....I was very confused about this topic

[@sayantanmunshi9969]

Detailed presentation should be like this. Thank You Sir

[@contacttaimur]

Many thanks. This video was really helpful. And its like The Godfather, I watched it 3 times and still enjoyed it.

[@riccardocandeago4699]

Thank you! This will help me with my geotechnics exam :)

[@ShashiKumar-yv7wf]

Thank u very much for this video. One of the best video I have ever seen. All my concept about this topic is clear now.

[@JamanMonir]

absolutely great tutorial or lecture. helpful for anyone who was in doubt like me. Thanks by the way

[@aveenaaspaudel8040]

In 13:55, you said that effective stress is greater than total stress, but in other books and videos, pore water is positive and it gets subtracted from total stress.

[@ferfixer2]

Thanks!! This video helped me a lot. However I do not understand why is in consolidated and undrained triaxial test the pore pressure negative. Could you tell me?

[@introductiontogeotechnical4976]

ferfixer2 When soils are sheared under drained conditions they can either contract (decrease in volume) if they are relatively loose or dilate (increase in volume) if the are relatively dense. This happens because soils are made up of individual particles that roll and slide over each other during shearing. If the soils are saturated and sheared under undrained conditions there cannot be any volume change (contraction or dilation) because both the soil and water are incompressible (relatively speaking). So instead of volume change during shear, there is a different reaction--change in pore pressure. Relatively loose soils generate positive pore pressure during shear because the soil wants to compress and push out some water. Relatively dense soils generate negative pore pressure during shear because the soils wants to dilate and draw water in. Hope that helps. I have some nice ideas for videos on this, but they won't be done for some time.

[@adriananazcocampoverde1918]

Introduction to Geotechnial Engineering Excelent!

[@krishnakadiyam2864]

@@introductiontogeotechnical4976 best reply of my utube life

[@scientificresearch1400]

@@introductiontogeotechnical4976 waiting sir

[@introductiontogeotechnical4976]

Vishabjeet Singh Rajput please see this webcast for an explanation dilation and contraction during shear. kzbin.info/www/bejne/jnSygYGDec2Loa8

[@luongtuananh1220]

very good demostration thank you a lot

[@James-oc3fr]

Thanks for video. it is really helpful for me to understand. good explanation. great

[@a7.tynxt_]

you're a total mvp sir

[@sarahgibson492]

Excellent, concise and clear!

[@gtrslayer1]

Thank you! Extremely helpful.

[@rawalali5182]

thank you sir . it helped me clear my concept quite efficiently.

[@parasbhatia6999]

very nice video . thank you very much for such a quality content.

[@eatedalalqusaireen3664]

Very helpful. Could you give practical examples when to use each test??????????

[@fabienwang5706]

worth more than my undergraduate degree lol, imaging being a geotech student and studying all the important stuff on YT......, says a lot about university education..

[@xavierariverahernandez5550]

Good Video. Thank you! The last part was the best!

[@krissiregar8083]

when explaining CU test, you must know the consolidation state of the soil speciment. just like +Adam Perez asked and +Riad L. explained. when the clay soil is NC, the effective stress envelope moves to left and if the clay soil is OC, the effective stress envelope moves to right

[@dr_greg_mouse4125]

This is a great video indeed. Thanks.

[@madhureddyindian9715]

Sir I love your explanation. I greatly appreciate your work. Love from India.

[@tonyk2038]

Thank you for this video!

[@frozentesla7771]

this video saves my life thanks Godbless

[@sagarsrsshah]

Cleared my doubts. Thanks!

[@davidliu2328]

thank you for being so awesome!!!!

[@mohamadoubanhoro9188]

great video on triaxial shear test

[@caebc]

The Best video

[@dragonborndovahkiin6523]

Yes

[@9076173238]

Amazing explanation!

[@CuteCookie96]

That was very helpful, THANK YOU!

[@DeepakKumar-hw1ih]

In Consolidated-Undrained Test, Why negative pore pressure is developed ? Why not positive pore pressure ?

[@SunitaDevi-sv2bo]

Thank you sir

[@superbananavoltex]

Hi, thanks for the informative video, I learnt a lot! However, there's something that has been bugging me. From what I understand on my notes and also from my search, effective stress = total stress - pore pressure. But from your video on the part of CU, effective stress = total stress + pore pressure? Do correct me if my understanding on the video is wrong.

[@rajatkushwaha4296]

for consolidated undrained test of normally consolidated clays in my textbook ....effective stress mohr circle is depicted by solid lines while total stress circles are by dashed lines also total stress circles are shifting right to the effective stress circles .....i.e effective stress are less than corresponding total stresses......i am confused.

[@hikuuuuuuu]

Thank you so much!!!!

[@bmansan]

Excellent explanation

[@leung77]

Dear Professor Kitch, may I raise out a question on the CU test that why a negative pore water developed such that effective stress is larger than the total stress, shifting the Mohr Circle to the right? Thank you

[@introductiontogeotechnical4976]

Dense or overconsolidated soils tend to dilate during shear, that is increase in volume. In this case, we’re shearing under undrained conditions, e.g. no volume change allowed. Therefore, instead of dilating, the soil responds by generating a negative excess pore pressure.

[@muhammaduneebalam5029]

Love you sir!

[@alxms10]

I have a question: in the last test (CU), first you allow water to drain slowly to measure sigma_3, and then close valve to measure excess water pressure, how did the gauge measure water pressure? Did you fill the sample with water again after drainage and before closing valve?

[@adamperez1993]

At 14:00 during the CU test why was the effective stress circle shifted to the right? Isn't this a positive pore water pressure? Negative would be a suction. Sigma' = Sigma - u

[@oussamaali8393]

+Adam Perez review terzaghi postulate

[@sanngo8002]

I think the pore pressure is positive, but the change in pore presssure delta u is negative.

[@nikossidiropoulos5627]

you actually wrote it Sigma' = Sigma - u, only that u is negative, so -(-u)=+u

[@shahzadikhan8356]

best explanation ever

[@yinminthann4822]

thank you Prof.

[@chrisronald2856]

really nice video

[@lulukobe8nba]

thx a lot Prof

[@DEEPAKKUMAR-lt6iy]

Very good videos I am happy with this

[@dann5480]

god bless the Americans!

[@nafiaykut6556]

I want to ask a question.I have calculated Fs from Michalowski’s (2002) 1.875 and I have calculated Fs=2.047 from slope stability program.What is the reason of this difference?

[@jacksonzheng4288]

Why do we have a negative pore pressure during the CU test??

[@JL-mj2eh]

It's depends on soil is normal consoilidated clay or over consoilidated clay. Each has different tendency of volume strain which lead to +or- pore pressure.

[@walidtlili7415]

I still dont get it

[@moipu8868]

I reckon if the sample is OC/very stiff it would dilate during the first part of shearing and so the volume of the sample would increase. The increase in volume would cause -(ive) pore pressure ...silly

[@saminyead1233]

Basically, pore pressure generally seeks to decrease the effective stress of soil. Thus, if pore pressure increases the effective stress, it means the pore pressure is negative. As to why this can happen, you have to keep in mind that pore pressure usually seeks to decrease effective stress only if the soil is saturated. In other words, the pore pressure is negative only if the soil is saturated. Here, during the CU test, since we drained the soil sample in the consolidation phase, a significant amount of water has left the soil sample and thus it is no more saturated. In unsaturated conditions, the pore pressure is negative. This is the reason for the negative pore pressure. If you want to know why pore pressure is negative during unsaturated condition, then I suggest you visit this link - environment.uwe.ac.uk/geocal/SoilMech/water/water.htm Hopefully, you'll get your answer. :)

[@CivilConqueror]

In CU test there will be effective stress in confining stage as per my imagination and concepts but hear taken total stress in confining stage

[@nimeshmakwana56]

Suparb explanation...👌👌

[@228MOHAMED]

God Bless you

[@khantahsinazad4250]

You are excellent

[@sevvalkursun16]

Thank you so much hocammmmm

[@pedrokaluf4189]

best video ever!! nice job

[@ashoktalks6108]

Thank you very much

[@hirasingh4495]

Amazing video!

[@parveshshukla3615]

its very helpful video

[@mdarifhossain3275]

Thank you so much.

[@baltichannelskardu]

Nice

[@krishanundas5497]

really nice presentation...

[@shaidleon9259]

Thanks a lot

[@albayrakcan]

awesome thank you!

[@ahmedobidat1743]

I read in your book (Foundation Design Principles and Practices 3rd edition) this statement. In general su (phi = 0) increases with depth because the lower portions of the stratum have been consolidated to correspondingly greater loads, and thus have a higher shear strength. Would you please explain why does consolidation increase shear strength? Thank you so much!

[@introductiontogeotechnical4976]

Consolidation increases the density and decreases its void ratio. This will both stiffen and increase the strength of the soil.

[@ahmedobidat1743]

Your the man! Thanks a lot!

[@MehsamTanzimKhan]

very good explanation! !

[@yektakaya4635]

does consolidating the soil mean the confining pressures are increased ? Because it says the soil is consolidated before being compressed

[@arking1208]

Thanks a lot, good lecture

[@bhandaribishnuhari7223]

everything is clear sir ..

[@victimboy7765]

Excellent! That is all I can say!

[@halilibrahimsahin4639]

Thanks from Turkey

[@introductiontogeotechnical4976]

You’re welcome.

[@chimoscreations9103]

amazing video

[@nikossidiropoulos5627]

13:21 - CU test, should the σ3 value at the consolidation stage be effective consolidated stress like in CD test at 11:53?

[@george6709]

no but you can obtain the effective stress by subtracting the pore pressure from the gauge

[@srimanideepallavarapu925]

excellent

[@hoggerz]

The Mohr's Circle for the Consolidated-Undrained test is incorrect. Effective stress is total stress minus pore water pressure (σ' = σ - ∆u). σ' would be less than σ, the dotted circle should shift left, not right.

[@willliamkitch2967]

The Mohr’s circles are correct. This soil in the animation is generating negative excess pore pressure during shear so the effective stress increases. Negative excess pore pressure occurs when overconsolidated clay or dense sand is sheared under undrained conditions.

[@mohituniyal4839]

thanx a lot.... great lecture

[@waseembhat2657]

great video

[@satishr5307]

Thank you :)

[@williamt.szeibert8699]

If CD takes longer to conduct than the CU, and gives you the same parameters as CU, when would you use a CD test over a CU test?

[@introductiontogeotechnical4976]

Precisely why CD tests are seldom done.

[@Hbalancev]

Thank you very much!

[@AdityaKumar-pv7mj]

Very nice sir