How Quicksand Causes Dam Failures
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- เผยแพร่เมื่อ 28 ก.ย. 2024
- In civil engineering, quicksand is more than just a puddle of mud! The "quick condition" occurs when seepage reduces the effective stress of a soil. This can lead to some dangerous conditions, especially if the seepage causes piping erosion to occur at a dam. Thanks for watching!
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This video is so good, *soil* subscribe to your channel.
J Sal
What?
J Sal ಠ_ಠ
"So i'll
Wow. You really had to dig deep for that pun.
J Sal i’m soilscribing to you
i blame science (& you by extension) for the lack of quicksand plot devices in today's television programming.
My life's greatest achievement
Ah, Hollywood quicksand.
aka, how an object that floats on water just fine, suddenly sinks in a fluid much denser than water...
The only people whom I would expect to sink in quicksand are screenwriters and producers...
there are still tar pits which have the benefit of not only trapping you from being able to move but you also sink since tar like most petroleum based compounds is less dense then water so animals being made mostly of water simply sink while not being able to move to get out. I am not sure why they aren't used as lot devices more often as they are truly terrifying and ARE a death sentence if you have no help to get out. thought there is the problem that they are too viscous to be used in movies as the movement is so slow that you would need a scene that is several hours or even a couple days depending on the viscosity to get the point across so not the most practical.
@@HPD1171 As far as I am aware, there is no record of a human ever getting stuck and dying in a tar pit. The remains of a single ancient woman were found in the La Brea tar pits, but it is believed that she was buried intentionally. They seem to pose a much greater threat to quadrupeds.
Indy 4 was not good for you?
But i must admit princes bride is way way better
Fascinating stuff. Could see myself getting into soil mechanics
Wait. How could the seepage water possibly goes up?
@@guyfriends1843 ???
It is a deep subject, but the basics can be compressed into a manageable size. This video just scratches the surface, the subject can expand layer by layer....
....Ok ill stop.
Of course im fun at parties. Why do you ask?
Now that it's been three years, did you get into it?
@@Abcwhatever lol
Leave a dam comment and let me know what you think!
You dam well, know what we think!
Would you be able to achieve a similar effect to the "cutoff wall" by making the base of the dam longer? It obviously wouldn't be as efficient, but would it work?
Practical Engineering hi grady great video as always ,could you make a video about ground vaccum and how it reduced water ,thanks before and sorry for my bad english
I'll be dammed if I do, sir!
Where can I get some dam bait?
Great video! However I felt like it was only the introduction. I was hoping you were going to spend a bit more time on the model and the various conditions or examples.
Agreed!
poster99999999 yeah, I was a little surprised when the outro started
me too, think he could have build a cutoff wall on the new model and have shown the difference between failure and a stable dam.
I too would have enjoyed more discussion of mitigation techniques, and some demonstrations of those techniques. Also some animations of actual dam failures and their causes would have been great.
Same.
3:16 "Engineers generally try to avoid building civil structures out of liquids" is the best sentence I've heard this year.
Dam that was a good video
*_Thlake you :)_*
Did you two just
Make horrible puns?
Yes.
I think you meant it was a great dam video :)
OH YOU!
These videos actually really help. I'm a general contractor so it's nice having at least a basic understanding of these things when I'm working with civil and soils engineers or when we run into problems in a job.
What? I wanted to see more of the model in detail with technical explanations!
Yeah, a slowed more thorough explanation of the mechanics instead of just short jumpcuts.
Yeah! More demo, less talking face, please! The talking itself is great, but I can’t concentrate when the visuals are gone. I could watch those demo model clips like 20 time without getting bored.
My thoughts exactly. I was waiting for a case by case demonstration with time-lapse sequences or so.
Koishi Komeiji it's quite a fine "line" (well, it's actually continuous, you could always increase the depth a bit and a bit more); popular science or in-depth science. This video could be 2 hours long with formulas and simulations (I would love that, honestly), but that would change the target audience. It's basically the difficult situation for a content creator to decide, how much to "dumb down" but still keep it interesting and scientifically correct. But still I agree with you, I want more, too.
That's not quite the point. The thing is that he seems to have got a bunch of awesome footage, but none of the experiments were presented from end to end. Maybe they're on another video. I personally was waiting for the point were he would stop speaking and let the experiment run. But you're right when you say that it's tough to produce a 5min video with everything necessary.
This is absolutely fantastic! As a civil engineering student myself in a land full of sub-soil water, I get really excited about this kind of videos analizing soil mechanics failures general,because we don't tend to visualize the phenomena this precisely. You are an inspiration and a great source of knowledge. Keep going! Hopefully, if someday I get to be a teacher, I'll make my students understad what they're learning through this kind of amazing demonstrations.
Greetings from Mexico!
That's a quality video. I wish there was more channels like this on youtube.
Mortumnus does someone know anyone like him on yt
For physics, PBS Space Time is definitely the best. And Kurzgesagt is good for science in general. Don't know about others.
There are actually many channels like this on youtube. The difficult thing is to find them.
3blue1brown, welch lab, real engineering
There's Vsauce, Physics Girl,Simone Giertz etc
Grady if you ever become a super villain you need to call yourself "The Hydraulic Gradient" get it? Because your name is Grady.... Dam it seemed more funny in my head... :) Anyhow keep up the good work.
i laughed; so, it was kinda funny!
Take your like and get outta here
@@feynstein1004 but why?
@@feynstein1004 Dammed if you do, dammed if you don't.
@Jeffrey Quinn Hah
Saw this channel for the first time. Great video and accurate description.
To prevent piping, along with cut-off walls/ sheet piles, inverted filters are used too.
Inverted filters are the ones with coarse grained on the top and fine grained on the bottom.
With increase in surcharge on the d/s side, the critical condition of hydraulic gradient is hard to occur
That got me thinking.
Could you mitigate the effects of piping by one of these measures?
-driving piles deep into the ground below the dam
-excavating deeper and filling the ground below the dam with a mix of soil, gravel and larger rocks
-injecting concrete into the ground below the dam
I seriously hate seepage. Ruins my underwear.
Excuse me what the fuck
Hahaha
The first time i heard him say it i thought he said "sea bitch"... 🙉
@@anitadervishi3807 i had to come to the comments to stop hearing "sea bitch"...
3:56
@@lescovar693 hey don't be racist
Even among YT channels dedicated to science the quality of your content stands out. Thank you very much!
Could you build a model showing the affects of fracking? With all the dialogue going on about this subject (both for and against), it would be interesting to see an engineer put it to the test in a controlled environment.
Dam, you must be under a lot of pressure.
That outro suddenly coming up after only a couple of minutes kinda caught me off-guard. It felt like the video ended just as you were in the middle of giving the lesson about this phenomenon. D:
I'd be interested to know how quicksand and liquefaction poses dangers to infrastructure and just structures in general, particularly in seismically active areas like the San Francisco and San Jose Bay Area where land has been reclaimed or even outright built using soil fill, as well as the considerations that civil engineers must make when designing for infrastructure and structures in such areas.
liquefaction is a major concern for civil engineers. It can be helped in a number of ways,
1. Avoid saturation of the soil by providing surface drainage or dewatering pumps
2. Create what's called a floating structure that is neutrally buoyant with the soil (usually by making a large basement)
3. Allow relief of soil pore water pressure through some mechanism such as an underground drain
These issues are well known and only really an issue in poorer countries where lack of maintenance, shortcuts or corruption occurs.
Although these issues are well known, they can still affect more economically developed regions as well. Particularly in areas that haven't been updated with infrastructure retrofits to solve these issues. Especially if it's a region that has a tendency to either neglect or conveniently forget about (or simply can't afford) infrastructure maintenance, upkeep, and replacement, until it just decays to the point where it fails outright and absolutely must be replaced.
Calyo, I felt that the video was short too. I think that he took more time building the model than showing it's effects and behaviours.
For one thing, the building "time lapse" seems longer than the demonstration footage xD
All soil liquefy if you shake hard enough. However you can do stuff to the soil to make it more resistant to liquefaction. Ground improvement like jet grouting to increase the overall shear strength of soil is one method. For land reclamation projects, the use of a correctly graded soil followed by sufficient degree of consolidation is one way of dealing with liquefaction risks during a designed seismic event.
@@Renegade30 Longterm mass dewatering cause other problems mate. Don't do it mate. The other 2 ways you mentioned are methods to deal with settlement and consolidation not liquefaction.
Could you maybe also do a video on QUICK CLAY- maybe also in relation to dams and other structures?
I know its quite similar, but it would be really interesting to see more about it!
This video was good. It was dam good!
I love how practical demonstrations such as model actually give you physical and easily seen information about the situation being modeled! :D
Currently im majoring in hydrology engineering on campus. This video is so helpful for me to understand about seepage. Thank you so much you dont know how much it helps.
I'd like to see the full time-lapse of the dam failure if possible, I'm a bit sad there were only a few scattered clips of it
Very strange that I've been watching a lot of your videos on dams recently just prior to 2 dam failures near my brother's house.
"engineers generally try avoid build civil structures out of liquids" i'd say thats an understatement
There was a work related accident on a construction site in Canada where the soil became quicksand around a cofferdam nearly killing a worker. There were 2 levels of ground water. The removal of the higher level of groundwater and soil being removed cause the soil in between to heave, releasing the lower level of groundwater. None of the testwells were deep enough to reveal the lower level of groundwater, so they did not know about it till the accident.
I wish our dams here in South Africa had more water in them.
Well you could fill those reservois with communist; they're not human but they are still made out of around 60% of water.
but communist is red. no one want to drink red water. they all want aqua-blue capitalistic democratic water.
Bennie Pretorius perfect time to enlarge the reservoirs when the water is low to get normal equipment in. Even if you make them so deep you can't get flow from them they still let water seep into the ground to recharge the ground water.
More capacity means when you do get rain more is captured and not lost out to sea.
Deep.
Reverse osmosis desalination plants powered by a nuclear reactor can deliver huge volumes of fresh water for hundreths of a cent per liter and they can run almost continuously for at least half a century. They're a good solution if water shortages are chronic and you live somewhere where people are capable of maintaining infrastructure.
your videos could easily be 20-30 minutes! they're a joy to watch and I ALWAYS learn something new. thank you!
Which is why you bring the footing down to bedrock.
Not everywhere has bedrock close to the surface.
Of course not. I learned that in geology class over 40 years ago. But, that just means not everywhere is suitable for a damn. ;) I left the latter unsaid as it is obvious to anyone who knows a bit of geology.
And over overconsolidated soil, clayey soil's bearing capacity is dependent of cohesion too.
This got me thinking: does everywhere have bedrock? I mean, do we just dig down until we hit a lot of rocks and call that "bedrock", or is it a solid slab of rock that literally spans the entire tectonic plate with no gaps (except volcanos I guess) and no way around it?
Warren Garabrandt , different areas have different types of bedrock and at different depths.
Sometimes a decent bedrock is just too deep to be economically viable to reach.
Manhattan has skyscrapers at either end because of decent hard schist bedrock; not so much in the middle though.
Practical Engineering has some great videos discussing liquefaction. Highly recommended
wow your videos are very high quality and also very informational thx for sharing! :)
You got me all excited with the clear explanation and the beautiful model of the dam and Bam!! The video ends all of a sudden!!
First quick, think of somehting funny...
.
.
.
Dam failure is what my parents call me.
Edit: wow internet engineering man likes me now.
I still get seepage after two shakes :(
lol:
internet engineering man
as a CE student this is really helpful to me as it helps me understand diff terms and how they occur
Great explanation. It also explains why the method to deal with a sand boil on a levee is to stack sandbags around to a height where the flow then stops.
3 Gorges Dam has been real quiet since this video.
My major was soil science in college. I graduated years ago but I adore your videos. It makes me wish I had pursued a career in soil 😢
Just wanted to let you know that I really enjoy your videos. This might get buried under an 'seepage' of other comments.. But just putting it out there
Grady, here's your dam comment...this is one of your best videos. I live in N. California and have been watching the work done to repair the Oroville dam spillway. Have you thought of discussing that event? Or perhaps talking about the reason a spillway is needed in an earthen dam - to prevent water going over the top of the dam itself. I'm not entirely clear on why water over the top of the same is so dangerous. Perhaps that could be a topic. Thank you and keep up the great work!
An earthen dam can have a good strength, but they don't resist erosion at all being made of unconsolidated materials. Water flow over the top washes material of the dam away faster than the water level drops, leading to a cascading failure. A spillway is supposed to allow an exit path for the water and energy behind it in a way that does not erode the dam.
"Engineers generally try to avoid building civil structures out of liquids" LOL!
I think the high vs low water pressure nicely demonstrates the entropy ;) The state where water is in a compartment under high pressure and the other compartment is empty is the state of low entropy. The entropy always grows, at least globally, so the water wants to go everywhere to spread evenly thus increase the entropy. One way to think about it, it is hard to make any work in high entropy state, for instance, no potential for electric turbines or water mills.
Did you know the Hover Dam was supposed to be twice as tall as it is now?
After some re-evaluation, they thought it would be 2 dam high.
I’ll see myself out...
Stay out.
a civil engineering student here !it is a great channel for me !
If this happens in real life
.... You will say "DAMN"
I believe this is what happened with the Malpasset dam in France. When i read the conclusion of the survey i thought the dam had detached from the mountain on one side but when i visited what's left of the dam (left untouched in memory of the many people who died that night) i noticed a huge hole in the ground going under the dam. So i think i understood the survey report wrong and what really happened was what you describe in this video. A very interesting and also very sad place to visit. A true example of the incredible force of water. I saw concrete blocks bigger than a house strewn miles away from their original place along the river bed, i just couldn't belive my eyes.
I'll be Dammed if any structure I build ever stands the test of time :) #dadjokeoftheday?
Thanks for the very informative videos, it's interesting to see how such inanimate stuff like dirt can reek havoc. Particularly how the piping causes a positive feedback loop
Thank you for putting so much effort to make regular people understand these concepts.
3:56 That was actually a lot more dramatic than I thought it would be. I was expecting some rinky dink "disaster" since it was just a model.
“Oh no, we’ve fallen into nesquick sand!”
Great video! I really enjoyed learning why my sandcastles always fall down whenever Im at the beach... and why dams could collapse if we arent careful...
The dams we built as kids in the ditch held up extremely well. We got grounded for washing out the sides of the road.
Hey Grady great video as always, but a little on the short side. Would've liked to see some more examples. Can't wait for the next one!
I recalled this video since the MI dam breaches - and glad it reappeared.
As far as I'm concerned, waterproofing is to dams and levees as bedrock is to bearing weight.
It would be great to see a little bit more of the model you built and if you could explain, what the experiments are about. It looks like you put a lot of effort into it.
I fell in quicksand one time & almost died!
If I would not have had my blow-up raft in my hands, it would have been curtains for me! It took me around 10 to 15 minutes of fighting, hanging on to this raft before I was able to climb out. You would think it would be easy to see right?
No, there is a fine, dry dust that covers the top of it so, it appears to be just like the rest of the ground.
I recall years ago that this sorta thing was mentioned in a class, and that one solution was to give the dam a "floor" to sit on so it wouldn't sink as easy. I don't know all the details because it's been years since I've seen it, but there's that.
as a mechanical engineering student your videos are great. i love what you cover， keep up the good work。
Levees usually use sheet piles or slurry walls to prevent seepage - they go all the way down below to an impermeable layer like clay, so most seepage paths are prevented to the greatest extent possible.
Can you do a video on the water table? What determines its height? Is it the same level as the rivers and streams? How is it taken into consideration when buildings are being put up?
This video is what makes youtube important, very simply explaining very sophisticated stuffs. A quick question, in your other video which explains the "mechanically stabilized earth", I wonder why home builders don't use this MSE technics to stabilize the soil beneath the house foundation? would u please elaborate on this
I really like this dam video, but I would like longer videos showing the flow rates with those fancy dyes. Maybe you can make another using your model and show how fast/slow it seeps at different pressure levels.
The phenomena was even greater than you guessed for the model.
this man explained everything in one semester for five minutes (sorry for my bad english languange)
The nature of the soil can often be determined by its electrical conductivity. Crays are very conductive but clean sand isn't. It is fairly common for there to be an old stream bed buried deep into the ground. It works as a path for water to move more easily so the path from above the dam to below the dam can effectively be shorter going down into the old stream, along it and then back up below the dam. This is why it is important to know what is below the dam down to a fair depth.
Good video. In a later video you might mention gypsum
and other chemicals in the soil that dissolve and speed
this flow along.
though piping is mostly associated with dam failure, it is an important geomorphological phenomenon that also occurs in the subsurface of (undisturbed) organic soils (peat), which formed under water-logged conditions. Therefore, liquefaction of the soil may play less of a role in the initial formation of soil pipes, but changes in shrinkage/swelling due to frost-heave and desiccation do.
those models are insanely good. Congratulations
You ar a very good engineering educator! Great to listen to you! All the best!
This was so cool, I wish it was 10 times longer!
You should do a video on how dams work to control flooding, and how varying the reservoir level has little impact on downstream flows. Lots of people think by reducing the reservoir level 6" the minor flooding downstream after a 100 yr storm will be reduced significantly.
Best video I have seen till now on quicksand condition on dam.. would have been more satisfied if the video could be longer explaining n showing the stuff more.
From watching your videos i feel like i have become a engineer!!
Thanks for another great video!! 🙏🏽
This made me remember the first law of hydrodynamics that we were (jokingly) taught in the water building course when I studied civil engineering: You can not fool water!
A local low Head dam near me that powers a still operating historic cider mill is currently experiencing something like this. Over the past several months the water has tunneled itself around the dam and the river now bypasses it completely. The state is currently trying to figure out how to fix this.
Super nice! It's funny to see someone who is also interested in these topics. Especially when considering I am doing a study here in the Netherlands (named Soil, Water and Atmosphere) where I learn about the same things as you show here. To be precise, at the moment, I'm following a course named Water quality & quantity, which is all about Darcy, Hooghoudt and such.
Ok now this person has everything I love to watch I’m subbing
Practical Engineering, I have heard that hydroelectric dams are harmful for their rivers because they make the outflow water "too clean", i.e. the water doesn't carry enough silt, compostable debris and nutrients downstream. Are there examples of dams that have taken this problem to heart? Conversely, have there ever been dams that have failed because of a buildup of silt/debris.
P.S., very cool channel! I only just found it today, but I have really enjoyed your work so far
I saw the aftermath of one of these. It was huge! Over 100 feet across and 100 feet deep. My dad called it a "sand boil". Ever heard that term before?
That quicksand played us like a Dam fiddle! :P
Never knew how interesting dams were, thanks for the videos
sub surface wall is a gamechanger
Best dam video I've seen in a while.
The seepage under the wall reminds me of the levees in New Orleans before Katrina. It was very common to see water seeping out from the levees all over the place. I believe it was one of the causes cited for the widespread failure of the levees when the water rose to the top of the i-wall levees. Lots of other issues but I think that was one of them.
Thank you, I wish you could show us more of the real time models
Really good video but left me wanting to see more demos of it and how different ground materials act.
Learned a lot! Thanks for putting this together!
Love the informative explanation. Would have appreciated more screen time on the model explaining the phenomena in action.
I love your stuff Grady. It’s always a please to watch and learn. Thanks.
What an incredible videol. I'm civil engineering student and I'm in love with this channel
Wow! You just made me realize i might be interested in geotech! Thank you! Very cool video and demos.
Have you seen the work on Boone Dam in East Tennessee? The dam in built in an ancient fault line.
okay, this video could have been 60 minutes long and i'd still have watched all of it. I'd love to know about soil types, and how the survey is done to determine the expected hydrolic gradient, what measures can be taken after construction if there are issues, etc.
I am learning seepage. This video helps alot.
I LOVE THESE VIDEOS SO MUCH I TYPED IN CAPS
The presentation, it’s.. beautiful…
Awesome work! Nice to see so much enthusiasm.
i know its a bit off topic, but i was wondering what you use for an adhesive on the plastic sheets and if you have an accurate way of scoring and cracking. I work with this stuff, and could use a few pointers. great vid! i like your way of presenting. I'm going to enjoy looking at the other vids.
I didn't understand the cut-off wall. But all in all it's a good video, thanks.
Suddenly gradient sounds like a portmanteau of Grady and regent to my ears.
"I'm Grady and I'll be your regent of hydraulics today - Your hydraulic Gradient, if you will."
Your videos certainly are the hydraulic Gradient that makes the blood seep into my enginerd brain. :-)
Excellent video as always!
I feel like a slow motion shot of your seepage model failing would be interesting to see.
I may never need this info, but I enjoyed learning it regardless.