L32 Cam-Clay model (Part 1): critical state line, yield surface and isotropic consolidation line

[@loknathdas3111]

Great explanation of critical state soil mechanics

[@Dauerglotzer123]

Great video! I'm trying to do a lit review on critical state/cam clay and was wondering if you had key references for this lecture I could refer to (sadly not sure I can reference a KZbin video as easy as that could be)

[@dnicolasespinoza5258]

You may want to check this link an references here: soilmodels.com/soilanim/#1645710166076-edb58d29-91c0 . However, make sure you do a thorough literature review on your own! : )

[@keyvankaveh3533]

Thank you very much for your nice explanation. I would be grateful if you might be able to explain how to apply MCC model in case deviatoric stress "q" is zero.

[@dnicolasespinoza5258]

Hi, this is in part 2: kzbin.info/www/bejne/gWWqqJafpb6dhaM Apologies for the late reply!

[@dmk1509]

Hi Dr. Espinoza, Thank you very much for the great lectures! I do have one question: How does temperature affect the yield surface in the MCC model? An increase in temperature seems to facilitate thermal compaction and cementation of soils, but earlier in your L23, you mentioned that an increase in temperature induces dilation. How do we reconcile these two effects?

[@dnicolasespinoza5258]

Hi MK, the answer is not straightforward. Very high temperatures reduce the size of the yield surface making rocks/sediments weaker and more ductile. Changes of temperatures within the elastic regime cause volumetric changes of the minerals and pore fluids within rock/sediments. The first one can be modeled with a temperature dependent yield-surface, the second with the theory of thermo-poro-elasticity (See Cheng, AHD. 2016. Poroelasticity. Springer). The key is to recognize which processes lead to either inelastic or elastic deformations.

[@juliansandoval8022]

Many thanks for these videos Dr Espinoza. Saludos desde Colombia

[@dnicolasespinoza5258]

saludos!

[@cheneric6854]

Hello, Dr. Nicolas Espinoza. May I ask that how does E (young's modulus) change when confining pressure is increased. We suppose E is gonna be bigger. But what theory or formula can be used to illustrate that result? Thanks

[@cheneric6854]

When confining pressure is increased, the rock changes from strain-softening to strain-hardening. But how does E change and by what theory to prove that.

[@dnicolasespinoza5258]

This is shown in the next video (Part 2: kzbin.info/www/bejne/gWWqqJafpb6dhaM). The Cam-Clay model handles elastic volumetric strains through the compressibility coefficient kappa. This is a non-linear elastic model, you could get a tangent stiffness modulus from here but this is not usually done, you just find kappa.

[@0713059059]

Thank you Nicolas. Rather than using the board, We can learn better :) Excellent!

[@mariogalindoq]

Could you explain please why the model doesn't consider the cohesion being that one of the most important characteristic of a clay is the cohesion? Thank you in advance.

[@Prophetic_heirs]

Thank you so much for the explanation!!!

[@dnicolasespinoza5258]

Typo alert: around minute 5 the correct equation is "Delta q / Delta p' = 3". Thanks to a viewer for pointing out the mistake!

[@wintthirimaw9839]

Dear sir, I am not clear about deviatoric loading and calculation

[@dnicolasespinoza5258]

check out this video: kzbin.info/www/bejne/gHazeJ9ol9WEo7s

[@pablosorosoto2360]

So, after the preconsolidation stress, there is not an elastic part on the deformation path?

[@dnicolasespinoza5258]

only if there is unloading, otherwise it is just calculated with the plastic stiffness matrix, see next video in the playlist (Part 2)

[@mariajosetoledoarcic7844]

muy claro y bien explicado! Saludos de Dresde!

[@b.y.7646]

hi thaks for this video, just one question : why the critical state line always crosses the origin? the cohesion of the soil is not taken into account with this model? thanks

[@dnicolasespinoza5258]

yes, the critical state line crosses the origin because most soils are uncemented and have zero cohesive strength. Some soils may have an apparent cohesive strength (undrained strength), temporary cohesive strength (capillarity and suction), or some cementation. The modified cam clay model can be modified accordingly to include cohesive strength and model rock behavior, see kzbin.info/www/bejne/oJjGpHuvh7Kbo7M and www.osti.gov/biblio/1238100

[@b.y.7646]

@@dnicolasespinoza5258 Hi, thanks a lot.

[@b.y.7646]

@@dnicolasespinoza5258 when you think about it, isn't it rather the opposite tendency that is evident? that is to say that most of the soils are rather cemented, aren't they?

[@b.y.7646]

@@dnicolasespinoza5258 another question : can suction make a sand soil like a cimented soil?thanks

[@b.y.7646]

i ask this question because i m a little bit confused. is cohesion create by fine particle (clay particle) or by temporary effects (capillarity or apparente strength). thanks

[@sanjb109]

Dear professor, in brittle rock the deformation characteristics fallowed by spawlling and rock brust.in real condition ...can u have any idea on prediction of rock brust in Tunnelling work.

[@dnicolasespinoza5258]

Hi, there are many reasons for rock spalling in tunnels. I am not an expert in tunneling. I recommend you check a book in tunneling.

[@KirillGoloviznin]

Like for not giving up on the ellipse :)

[@samhsiao87]

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