CEEN 341 - Lecture 23 - Lateral Earth Pressures, Part I

This lesson introduces the concept of lateral earth pressures and how geotechnical engineers compute them using lateral earth pressure coefficients. The differences between active, passive, and at-rest cases are explained. Rankine passive and active earth pressure coefficients are derived for cohesionless soil, and an example retaining wall problem is solved.
Learning Objectives:
1) Explain the differences between passive, active, and at-rest lateral earth pressure.
2) Compute the Rankine active and/or passive lateral pressure coefficient(s) for a given cohesionless soil.
3) Solve the equivalent lateral earth force (active or passive) acting on a wall, including the possibility for multiple soil layers, water behind the wall, and a surcharge on top of the wall.

[@avosolakian5837]

I pay around $20K per year for tuition fees for my university and I had to watch your video to understand LEP. Thank you very much for doing this for free, really appreciate it

[@moonisansari282]

same here bro in university teachers are just reading from their PDFS and they don't care whether students are understanding the concepts or not....that's why i have to watch TH-cam every time to get clear concepts for the topics being taught in class

[@woohoomanful]

I work with earth pressure as a temporary works designer, you explain this so well and your visual aids are perfect! When I heard your accent I was dreading the units being pounds and feet! Thanks for doing it in metric.

[@alextemus]

Hey Prof Franke, just reviewing this as I'm preparing for the PE structural exam. I appreciate how much effort and care you put into your time as a professor and wish you the best! Thanks for everything.

[@Maddsization]

I’m studying for the PE right now after working in civil engineering for 4 years. This video is saving my life in helping to teach not only the equations but the theory that makes us better engineers. Thank you so much.

[@bathrrom]

What PE Exam are you taking ? I am also in the process of studying.

[@christianhillary5433]

Thank you for making these lectures open to the public. These are the best lectures on soil mechanics. Sir, Would you please upload the lecture on stress path

[@basilthecornsnake]

A heartfelt thank you for this exceptionally clear presentation. Love your broken-down and "reassuring guidance" approach to teaching!

[@hurtamor6445]

I really hope that in every 55 mins I spent in any class would be very productive, informative and enjoyable as much as when I watched this video lecture. Thank you sir.
Every word that you said is important in order to understand the concept. And the steps were amazing.

[@akihisa7635]

I was so doubtful at first clicking on a 54 min. lecture but this sir was all worth it, ty so much for this.

[@ryancowles5633]

I've been out of college for 4 years now and I haven't understood LEP's until now. Thank you for all this! My geotech professor was...foreign...to be polite and couldn't communicate in a way that I could understand the concept and the math behind it.

[@Czar684]

Thank you very much! One of the best YT lecture on a topic that I've watched.

[@abdulhaq2517]

Thank you very much for making easy to understand this subject clearly, way of Teaching/explaining things are intrseting.

[@elmorro901]

This is great! Took me back to my college classes. I'm in construction management now, but i like to refresh myself on lectures like this every now and then. I loved soil mechanics in class. Thanks!

[@mohdiqbal599]

I Thank you for your effort. Quite beneficial for geotechnical academicians and practicing engineering.

[@mohamedelmi4702]

thank you very much ... you increased my understanding for this chapter .. God Bless You

[@tanvirtscientist608]

this is the best lecture ever in my life! thank you for your kindness!

[@reza1001us]

It was a great explenation for LEP problem. Thank you.

[@crazypinky97]

Thanks for this! You have saved me for my soil mechanics exam!!

[@WonderFilledCow]

Thank you, very clear and easy to understand.

[@safihalim3747]

Thank you very very much! Brilliant video!

[@emmanueltuakehwuo4789]

Thank you for the great presentation on this course

[@flourishomotola5306]

Very easy to understand. Thanks 🙏🏿 sir.

[@DanielPeraalta]

thank you so much, I learned exactly what I needed!

[@kimiversen4655]

Brilliant presentation 👌

[@ChaymaeIbrahimi]

Thank you so much sir really , the way you explain is perfect .

[@SavasPapasokratis]

every engineer should watch this

[@surayasuran215]

Thank you very much.... REALLY A GREAT JOB !!!

[@xxjacksparrowxx6742]

Tujhe kya samajh me aya be

[@phebomoralestapel5348]

My professor even speaks in English and our language but your lecture is far more understandable than him. And we take almost 3 hours for that, compared to almost 1 hour in yours. Thank you very much for your efforts to make it easier to understand. 😉 🙏

[@lifequotient]

Thank you for this!

[@ZWSFC]

Brilliant video!! Thanks Doc

[@ernestoherrera807]

Thank you for sharing.

[@Ram-vl7qb]

Thank u..I like ur way of explanation...

[@dicksonadjarani1921]

thank you, sir for a very clear presentation. May I share this to my students?

[@ashrafmelek1698]

Thank you

[@karlmichael4215]

Thankyou so much sir

[@farahjama9712]

Thanks Sir, Tomorrow afternoon i have Soil Mechanics Final exam, Thnks for your helping, i expect this type of question tomorrow

[@medimpleboi]

Great Lecture 🌹🌹

[@mariagonzalezbracho2315]

pretty good, excellent explanation

[@burakcakir8190]

at the beginning i was confuced about should i watch it or just skip, i chose first one and i appreciated very much thank you sir

[@abdallahmahjid283]

hello prof! explained it very well, however I can't seem to understand why we took different Ka values for when the soil changes but not for the surcharge pressure? thank you

[@homayounshirazi9550]

And I am just a curious George wanting to know how to stop my knee wall from tilting forward and I found out I needed to change the soil behind the knee wall to increase its stick-with-it-ness to keep the knee wall where it is. Thanks.

[@kilangojr2553]

thanks a lot, for making it easy..

[@stooncol619]

Sir you are a sainte thank you very much

[@mjunaidasghar8613]

Thank you...very good presentation

[@ab20ification]

Awesome Lecture

[@anthonytsai4358]

Thanks!

[@changjin1229]

in step 5 of the example, i think the bottom layer should be shorter, as the 24.5 in the middle layer is longer than the 23.4. Other than that, this is awesome!

[@mettaimed6586]

thanks a lot teacher

[@snoopywee]

this was excellent

[@testbh]

how about the hydrostatic uplift, causing a unfavorable moment force

[@hh-bz3li]

SIr, very nicely explained. How to calculate soil pressure during lateral pile(circular) force?

[@malikmurtaza24]

thank u so much sir...It was really a good lecture.

[@jamalnaser1933]

Kudos to you

[@JLHOLT91]

Isn't it a cantilevered retaining wall because we are trying to design with a fixed connection at the base, and no restraint at the top?

[@alsbro1234]

I saw another video of that said because the wall is at rest, calculate Ko (instead of ka) using 1-sin(phi). Is that incorrect?

[@c.j.5751]

do u have the answer bruh?.. i am currently looking for that answer also

[@viggoarnesen9671]

Can you please explain how i differ this load with or without load factors ? As I understand this is without load factor. I dont understand the difference between effective friction angle σ` and σd.

[@jaysalerno5446]

Why is Shape 3 a SQUARE and not a TRIANGLE? Why is its sigma consistent with depth such as with Shape 1?

[@ianilutwa5805]

nice

[@Patrickorwa]

Metric ,awesome

[@ing.erickosorio2887]

I was wondering what happens when we have an inclined wall, lets say 60° with respect to the horizontal axis, and we have earth underneath that inclined wall, as for example in a water channel, where the walls are not vertical but they must be inclined in most cases. I kind of think that in that case it would be the soil supporting the wall which is resting on the soil and not having to be design agaisnt any active pressure. am I correct?

[@belindal.2270]

Hello Dr. Franke, can you please tell us the answer to the final step (location of the equivalent force)? I calculated 2.48m from the bottom of the wall. Thank you

[@omer-zz5gq]

I got 2.4m from the bottom of the wall, so i guess you're fine

[@NN...1809]

Doeas anyone knows, what if we have a cohesion soil fully saturated (water).. Do we count the active pressure (minus porus water pressure) or do we measure only the total pressure (without the water) e.g. Kaxσtot instead of kax σ' - γwxz

[@hkg4295]

Is it necessary to know the existing ground level to design an anchor wall when you already have a road and platform level? This is my first time doing geotechnical work, so I’m a little confuse and full of hesitations 😰

[@michaelm-bs2er]

does anyone else think he sounds like David Duchovny?

[@Jayce1712]

Can u upload one on eurocode, no pressure but really need it

[@rycoolhead]

for the equation of Pa at 29:15, why isn't it 2/3 rather than 1/2 since it is a triangular shaped load?

[@officehours4028]

2/3 the height is used to locate the centroid from the top of a triangle. We are dealing with areas, not centroids. 1/2 base * height gives you the area of a triangle.

[@rycoolhead]

@@officehours4028 Thanks. Ya I figured it out shortly after. Got some reason I thought you were calculating the moment with that

[@TheTiger1375]

Bearing capacity please

[@alxms10]

Hi
Is there no Lecture 22?

[@paigewilloughby8804]

4L4U 4ever!

[@aliabdulrazaq512]

1000 LLLLLLLIK with 1000 thank again.

[@1yoan3]

Why start with the hardest of problems when we barely got introduced to the subject :'(
Not very pedagogue.

[@1yoan3]

I must add: this is still by far the best lecture I have found on internet regarding geotechnical engineering.
Edit: typo.

[@intothenature6415]

hey,You are doing it wrong .The effective stress due to saturated soil will be soil minus the pore water pressure .You shoulhd substract water pressure from pressure due to saturated sooil.

[@officehours4028]

Whether you use a buoyant unit weight or you subtract water pressures from the equivalent fluid pressure from the saturated soil, you will get the same result.

[@intothenature6415]

@@officehours4028 got it .