CEEN 341 - Lecture 20 - Triaxial Shear Test

This lecture introduces the triaxial shear test. The consolidated-drained (CD) and consolidated-undrained (CU) tests are explained and demonstrated. The drained and undrained Mohr-Coulomb failure envelopes are introduced.
Critical Questions to Consider:
1) Why would we want to use a triaxial shear test instead of a direct shear test?
2) What is the difference between contraction and dilation during shear? What does contraction do with the fluid in the void space? What about dilation? What types of soils tend to exhibit contractive behavior? Dilative behavior?
3) What are the differences between the CD and the CU triaxial tests?
4) What is the difference between the drained and the undrained failure envelope?

[@rioanantaperangin-angin713]

This is literally the best lecture on soil mechanics I've ever found. Well, I'm not grasping the whole stuff well, but I actually understand what's happening (especially what happen if the soil dilates or contracts). Thanks for sharing!

[@ryancowles5633]

You are helping me study for my PE exam good sir. Thank you for all the work you put into making these. My geotech professor 5 years ago was more worried about his research and not teaching throughout my course it felt like.

[@abinashmandal6202]

You broke down the very complex topic. Finally understood

[@ittichaiboon88]

Bring out the RAM! your tutorial is the best for soil mechanic in internet. Thank you sir

[@bannuchen]

Your students can be lucky to have somebody like you teaching them soil mechanics. I am from Germany (THE engineering country), nevertheless, none of my professors was able to explain things as you do.

[@sungryoo9239]

Sir, your videos are so easy to understand. Thank you.

[@LyndaAngarita]

Thank you!, I'm studying for my PE license and I finally after so many years understand the concept! thank you again for sharing!

[@user-ld5uv4uh8m]

Thank you for the great explanation. The procedure for obtaining soil samples for testing equipment is not clear. Take a soil sample with a rough N value using a standard penetration test. The operation is performed without knowing which depth of soil is suitable for the soil sample. If stones are mixed in, the inspection machine will not work properly. Obtain it at 1cm along with the N value data using an in-situ test machine. At the same time, data on loading, rotation, and settlement amount will be obtained. Perform the calculation to obtain C and φ. At that time, the singularity can be identified as the part that is causing the slope failure. C and φ are design data for renovation and construction, and must also be used as data for disaster prevention.

[@christianwireko5871]

The part about trying to "trick the soil" got me so hard...You are brilliant and funny. Thank you!

[@khenirajesh]

Simply Amazing. All my doubt got cleared. Very unique way of introducing the concept. I loved it!

[@sisiriitr]

best Geo video I ever watched, so good clear explanation and to the point. wish to have more videos to cover full lecture on geotech and foundation engineering.

[@gauravgiri6818]

Thank you sir for such an awesome lecture. It was very helpfull as well as easy to understand the concept behind the triaxial test.

[@sunmoon7501]

Soil mechanics used to be kind of torture for me.... ram... thank you for the videos.

[@jitendrakumararya1163]

best lecture 🙏

[@RameshGau]

Nice video to brush up my idea on Triaxial shear test.

[@clem5474]

Legend, absolute legend.

[@bankai7100]

Thank you for these videos!

[@soroushnazari5596]

That's awesome. i understand the whole concept very easily.

[@abimbolalasebikan4841]

Thank you so much for your videos.

[@exambuddyyt7896]

You are amazing! Watched your videos. They are very informative! Thank you. :)

[@coffeeaddi8t]

Really helpful! Thank you!

[@paulwakoli4696]

Please do a video on slope stability.

[@ginosimon9094]

excelente

[@civilengineeringknowledgeb2955]

How would the back pressure affect the total stress envelope of CU test on sand?

[@georgechristiangyedu-nuako1171]

I would like to know why some cohesion was measured in the undrained test and non was measured in the drained test. does it mean that cohesion will never be recorded in a drained test and there will always be cohesion in an undrained test?

[@mettaimed6586]

hallo professur thanks a lot for theses videos , I have a question if you can help me, on which basis the values ​​of lateral stresse are chosen, for exemple in the triaxial shearing test we take generaly 50, 100 and 150 bars for soils

[@syedjamalarbi2000]

It's not just lot to swallow but too too muccccccchhhhh to swallow😂 but love it. Thanks❤️

[@shahofheartz]

Thanks. Can we have few lectures from 641Advance soil mechanics specially on consolidation and liquefication?

[@simengg7824]

Professor, I have a question which is draining me from last couple of days, which made me visit this video. The doubt is that if there is a slope and i do the excavation on that slope, For accessing the immediate stability FOS and Long-term stability FOS. Which of the shear tests should i perform and why!. I thought about it like this, that immediately after the excavation and because the soil is clay, it can be thought of as a Drained soil because previously the soil has had the oppurtunity to drain away Excess pwp. so i thought of doing a CD test for Immediate stability For the Long term stability , i thought that it is a case of unloading(excavation) and since the soil is clay, it will show an increase in pwp hence i thought of doing an CU test. Please help me knowing the validity of my thought about the problem, that will be much appreciated.

[@rawadakl3895]

Are you referencing from the Braja Daas and Khaled Sobhan ?

[@ol1163]

For OC, phi(effective) should be larger than phi(total) right?

[@dhuraiathi5291]

Very exotic

[@lucasbatista8169]

Where can I find the lectures from 641 Advanced Mechanics?

[@lalitajoshi5240]

Lucas Batista hello there, do you know any channel where I can get lectures on other civil engineering subjects for undergraduate students, similar to this?? I'll be very grateful if you could tell me about any.. :)