[HN Gopher] Why Retaining Walls Collapse
___________________________________________________________________
Why Retaining Walls Collapse
Author : chmaynard
Score : 166 points
Date : 2021-12-07 15:28 UTC (7 hours ago)
(HTM) web link (practical.engineering)
(TXT) w3m dump (practical.engineering)
| ksec wrote:
| Saw the video on YouTube and thought about posting in on HN, but
| somehow I felt Video content generally dont belong to HN, so I am
| glad there is blog version and getting some attention.
|
| I am much more interested though to know why it was already 4
| years behind schedule.
| rob74 wrote:
| > _Depending on the steepness, it's either inconvenient, or
| entirely impossible to use sloped areas for building things,
| walking, driving, or even as open spaces like parks. In dense
| urban areas, real estate comes at a premium, so it doesn't make
| sense to waste valuable land on slopes. Where space is limited,
| it often makes sense to avoid this disadvantage by using a
| retaining wall to support soil vertically._
|
| As someone born in a completely flat city and now living in
| another completely flat city (600 m higher, but still flat), I
| always kinda liked slopes, especially sloped house plots - they
| force architects to come up with creative solutions instead of
| cookie-cutter boredom. But I didn't realise how far people's
| dislike for slopes can go until I saw this monstrosity near Nice
| (France) while on holiday there:
| https://goo.gl/maps/zf5H1jSA855bSa4XA (you can take a better look
| in the 3D view). That's right, they must have excavated a whole
| lot of rock there, and are putting up with a ~ 20 m sheer rock
| face right next to their houses, just so they can have nice flat
| plots of land! Ok, it's rock, so probably more stable than a
| retaining wall holding back dirt, but I would still be worried
| living next to that precipice (either above or below) - if not
| for my immediate safety, then for the long term value of my
| property...
| orthecreedence wrote:
| I live on a hill, and the driveway ends below the house, so
| when we need to haul up materials (gravel, lumber, etc) for
| various projects, it's walking up a bunch of steps and
| slippery/muddy hills. I don't mind slopes on their own, and in
| fact quite like the exercise for every day use, but when you're
| hauling buckets of gravel or a cord of firewood, it sure would
| be nice if you could just load up a utility cart and walk it
| over to where it needs to be (or hell, drive your truck across
| the yard). It's not possible where we live because of the hill.
| So I can absolutely relate to why people don't like to live on
| a hill. And for hanging out outside with friends, you can't
| beat flat areas.
|
| That said, the view is really incredible (we live in the woods)
| and we don't get water pooling in our place or flooding or
| anything like that thanks to some well-designed drainage, so,
| you know, pros and cons.
| jefftk wrote:
| What makes you think it was excavated from a continuous slope
| instead of naturally being a near-cliff?
| rob74 wrote:
| If you look at the area in the 3D view in Google Maps, it's
| pretty obvious - the plots left and right of this small
| neighbourhood are on a slope, just there the terrain is
| almost horizontal...
| ggm wrote:
| Calls out for pictures. Begging for some diagrams.
| mitchdoogle wrote:
| Did you watch the video? That's the primary content. The
| article is basically just the script for the video
| ggm wrote:
| I did not. Thanks, good call. [Edit] Then, later on I did.
| His graphics and cutaway models are really good.
| jdavis703 wrote:
| Perhaps this is usual, but when Caltrain was building the new
| approaches for the elevated Hillsdale station I noticed they were
| just pouring concrete on top of plants.
|
| Maybe not the biggest deal, but I'm pretty sure the engineering
| algorithms assume a solid mass of concrete. Hopefully there's
| enough safety margin that this doesn't matter.
| SECProto wrote:
| Not usual - what sort of plants? What did the concrete look
| like it was doing?
|
| Organic material would be fine if it was underneath eg, a
| temporary pathway or something, but that's about it. Actually
| it might also be fine for secant pile cap (talked about in this
| video[1]): when you drill a secant pile, you generally pour a
| concrete cap (that then gets drilled away).
|
| [1] https://www.youtube.com/watch?v=UF9FLUioZv8
| jdavis703 wrote:
| I would describe these plants as large, probably seasonal
| weeds. So it's not like they were woody trees or anything.
| Just seemed kind of shoddy.
| SECProto wrote:
| If you click the image at the top, it will load the youtube
| video[1] (which is the better source in my opinion - the blog is
| essentially closed captioning for the video, without any of the
| graphics). The only indicator is a small play triangle in the
| centre of the image/link - the cursor doesn't change on
| mouseover.
|
| [1] https://www.youtube.com/watch?v=--DKkzWVh-E
| kevincox wrote:
| I agree. I already watched the video and was surprised that I
| couldn't find a link from this page. The fact that the header
| image is clickable is very non-intuitive. At the very least the
| cursor should change on hover.
| rob74 wrote:
| I realized something was fishy when I read "I'm Grady and this
| is Practical Engineering" at the end of the first paragraph...
| but still, I appreciate these articles, easier to skim through
| than a video. And if you're really interested, you can still
| watch the video...
| SECProto wrote:
| That's fair - I've just watched a lot of his videos (I think
| they're great), and the visual aids really make the
| explanations intuitive.
| mikewarot wrote:
| I live in a very flat part of the US. I always assumed that the
| opposing retaining walls were tied to each other. I'm surprised
| there's no real anchor to this stuff.
| zie wrote:
| The earth IS the anchor :)
| kjander79 wrote:
| Can someone explain to me why the brickwork in the picture in
| this example is just separated columns, using the cap to hold
| them together, rather than interlocking the bricks? I'm sure
| that's not the reason the structure collapsed, but once there's
| movement in the wall, it seems like that would contribute to loss
| of cohesion.
| hinkley wrote:
| He covered this type of construction in an earlier video, and I
| think this is the key line:
|
| > Gravity walls and mechanically stabilized earth are effective
| retaining walls when you're building up or out. In other words,
| they're constructed from the ground up.
|
| The soil behind this type of wall is supposed to have been
| stabilized by layering a tension material at intervals to keep
| it from moving. There's a demo of compacting sand with layers
| of cloth and then using the cube of 'sand' to support one wheel
| of a car. The material sags slightly and then holds.
|
| My understanding is that those concrete puzzle pieces aren't
| predominantly load bearing. Mostly they are for erosion
| prevention and perhaps moisture control (not just keeping water
| out but keeping the hydration consistent over time and
| distance).
| hamburglar wrote:
| Yes, he goes into it in more detail on the video about
| mechanically stabilized soil, but the techniques used to
| stabilize the soil mean the wall is entirely stable without
| the concrete face, and the face is there to keep the soil
| from getting eroded away and to look nicer.
| pomian wrote:
| Great little video explaining all the hidden engineering and
| technology that we don't see. As with any good presentation, nie
| we have questions. For example, how do you prevent that slump
| from happening, that he showed at the end? How did engineers fix
| those broken highways? Then part two? I assume, would be to show
| how soil, ground analysis works, with drilling, sampling etc. to
| define stability, and what engineering used for that.
| h2odragon wrote:
| I helped build earthen structures with sharper slopes than 25
| degrees 30 some years ago that are still holding back ponds
| today. "Soil compaction" is the magic that can turn native earth
| into a real wall that will hold load for quite a long time. The
| surface treatments, bricks or vegetation or etc are not load
| bearing, they're a skin to prevent erosion, much like paint on
| steel.
|
| I'm slightly puzzled it doesn't get mentioned here. Has this
| knowledge been lost? I've not been observing construction work
| first hand for a while but I don't recall the last time i saw a
| sheep's foot roller in use.
| mckeed wrote:
| Does that vary with the type of soil? I wonder if the 25
| degrees he mentioned is an average based on the properties of
| the soil.
|
| Either way, you can't really get to an angle that would be
| considered a "wall" without mechanical reinforcements, can you?
| hh28b9b17bf197 wrote:
| It is mentioned at 6:32 in the video. As other comments have
| mentioned though, its not clear that this article is a
| transcript of a video
| SECProto wrote:
| > I helped build earthen structures with sharper slopes than 25
| degrees 30 some years ago that are still holding back ponds
| today.
|
| I think you may be mistaken - note that a "25 degree slope" is
| just a different way to say a 2 to 1 slope (2 feet across, 1
| foot up). I've seen 2:1 slopes used for highway embankments,
| but earth fill usually specified as a 3:1 slope (18 degrees) -
| eg when I worked with an earth fill dam (holding back water,
| same as yours). I've only seen anything steeper (1:1, 45 deg)
| used a as a temporary (during construction) condition.
|
| Sheepsfoot rollers are good for packing very fine material
| (silt, clay) but not very good for packing larger granular
| material (i.e. crushed stone/gravel). Silt and clay are very
| water sensitive materials: each has a very specific moisture
| content where it can be packed properly, if your material is
| outside of this narrow range it will not get to maximum
| compaction (and therefore it will eventually settle). Water
| moves very slowly through clay so if it is too wet or too dry
| it's very difficult to get it back into the proper moisture
| range, and if there's a bit too much sun or some rain between
| excavation and placement it will not get packed well. The only
| reason I've seen clay-ey earth intentionally used is for
| inhibiting water movement, IE an earth fill dam - and even
| there, it was a secondary barrier if anything happened to leak
| through the barrier membrane.
|
| Crushed stone is (relatively) very easy to get to maximum
| compaction, and if it sits out for a while and gets too dry you
| can just hit it with a water truck before placing. It packs
| quickly and easily, and is stable at the ssame side slopes as
| earth fill
| h2odragon wrote:
| Yes my experience is dated and my memory none too good, thank
| you for expanding. My experience is all with "perfect" high
| clay soils and I'm sure many of our jobs were "under-
| engineered" to put it politely.
|
| We had some _crazy_ operators who would do things like
| chaining the dozer to a trackhoe at the top of the hill so it
| would not roll over, to do the final grade of the slope.
| There 's more laws now, and/or fewer fools with earth moving
| equipment.
| SECProto wrote:
| > Yes my experience is dated and my memory none too good,
| thank you for expanding
|
| No worries, when I heard 25 degrees my gut reaction was
| "that can't be right". Then I did the calculation and saw
| that the common ratios used are a lot fewer degrees than I
| expected :) I was thinking of grades in percentage (rise
| divided by run expressed as a percentage - so 50% for a 2:1
| slope, 33% for a 3:1, etc)
|
| > There's more laws now, and/or fewer fools with earth
| moving equipment
|
| I think stricter rules (or enforcement thereof) has led to
| the proliferation of long-reach excavators.
| Enginerrrd wrote:
| I'm a civil engineer, soil compaction is still critical for any
| grading fill and will continue to be important. One of the
| biggest issues though is that it can be really hard to compact
| native material to the required spec. It has to be perfectly
| within a narrow window of moisture content +/- just a few perce
| t to achieve full compaction.
| krisoft wrote:
| > I'm slightly puzzled it doesn't get mentioned here. Has this
| knowledge been lost?
|
| Clearly not. He talked about soil compaction in earlier
| articles:
|
| In "Why SpaceX Cares About Dirt"[1] he talks about soil
| compaction through surcharge loading.
|
| In "What Really Happened At Edenville and Sanford Dams?"[2] he
| talks about how the lack of proper soil compaction was one
| reason behind the dam failures.
|
| In "Why Does Road Construction Take So Long?" he identifies
| soil compaction as one of the most time consuming parts of road
| construction.
|
| If anything he didn't talk about soil compaction in this
| article to avoid repeating himself. :)
|
| 1: https://practical.engineering/blog/2021/10/28/why-spacex-
| car...
|
| 2: https://practical.engineering/blog/2021/10/14/what-really-
| ha...
|
| 3: https://practical.engineering/blog/2020/6/1/why-does-road-
| co...
| jacobolus wrote:
| Additional relevant videos:
|
| https://practical.engineering/blog/2016/5/15/mechanically-
| st...
|
| https://practical.engineering/blog/2017/6/28/how-do-
| sinkhole...
|
| https://practical.engineering/blog/2018/7/1/how-soil-
| destroy...
|
| https://practical.engineering/blog/2018/7/16/how-
| quicksand-c...
| tda wrote:
| I can assure you surface compaction is still a thing. Never
| seen sheep's foot rollers, but I have seen really big square
| rollers. A square doesn't roll very well, but that is the
| point: every tumble it makes it crashes into to soil. Problem
| is it is extremely uncomfortably for the operator, even if
| pulled by a really big tractor. These rollers are called impact
| rollers.
|
| Also in use are rapid impact compactors, basically a crane
| pounding away. Vibro compaction, where 30m long vibrating
| needles are driven into to soil. And best of all, Dynamic
| impact compaction: lift a big chunk of concrete 50m in the air
| and let it free fall. Then do it again and again... See
| https://vimeo.com/415927984 @ 3:15
| jerf wrote:
| Soil compaction has been covered in a couple of other Practical
| Engineering videos.
|
| It seems several people are complaining that a transcript of a
| ~10 minute video isn't an entire engineering education in all
| possible details of how to create retaining walls. I think
| that's asking for an awful lot. But at the very least let's
| credit the things already discussed elsewhere.
| VintageCool wrote:
| Given that this is a transcript of a video, and that video
| has pictures and diagrams to help illustrate what is being
| discussed, I would have really liked to be able to see those
| pictures and diagrams interspersed with the text while I was
| reading.
| nightpool wrote:
| It's kind of surprising to learn that this is a transcript!
| The "play" icon was really easy to miss for me and almost
| entirely blended in to what I now realize is a video
| thumbnail (I thought it was just a header image!).
| cf100clunk wrote:
| Show me a homebuilding article or video that doesn't discuss
| essential tools - that's kind of my issue with not mentioning
| Proctor Tests in this context, as they are fundamental at the
| pro geotech level. Its not too much to ask.
| jerf wrote:
| How many other equally important things are also not
| mentioned?
|
| I'm going to find "zero" very hard to believe, what with
| this being a 10 minute general audience video. I seriously
| doubt I'm just three additional minutes away from being an
| expert on the topic ready to take on any geoengineering
| task I could desire.
|
| Edit: Let me put it a different way. While I watch and
| enjoy his video series, I've been showing them to my
| 10-year-old and 13-year-old kids, and I'm pretty sure
| they're not that far out of the target audience.
| cf100clunk wrote:
| Well I won't belabour this, as the definition of
| "valuable" information can be as amorphous and/or
| personal as that of "quality". Glad that website and its
| videos are out there anyways, and glad somebody may have
| learned about Proctor Testing.
| jasode wrote:
| _> discuss essential tools - that's kind of my issue with
| not mentioning Proctor Tests in this context, as they are
| fundamental at the pro geotech level._
|
| The top 2 videos from the following Youtube search results
| about "retaining walls" do not mention Proctor Tests.
|
| https://www.youtube.com/results?search_query=retaining+wall
| +...
|
| And halfway down those search results is a retaining wall
| video presented by geotechnical engineer Andrew Lees that's
| _longer in duration_ than Grady 's video and he doesn't
| mention Proctor Test either:
| https://www.youtube.com/watch?v=HGuX7rmzlzA
|
| And after reading the wikipedia article about Proctor
| Tests, I think Grady made the right _editorial judgement_
| to omit that topic from a 10-minute video _targeted at a
| general audience_.
|
| Or put another way, if cf100clunk made a video about
| retaining walls and was constrained to 10-minutes, you
| would also be forced to leave out some essential topic that
| other geotechnical engineers would criticize. You can't
| please everyone when you have time constraints.
|
| EDIT add: thanks to other's links, I noticed that Grady
| already mentioned Proctor test in a previous June 2020
| video _" Why Does Road Construction Take So Long?"_
| cf100clunk wrote:
| No need to call me out personally for my observations. It
| isn't an HN thing to do. As I've said in another post,
| glad the website and video are out there, and glad to
| inform folks about the Proctor Test.
| gerdesj wrote:
| Civ Eng graduate that ended up in IT here. For home projects,
| please consider gabions as well as the usual suspects when you
| are building retaining walls.
|
| A gabion is a galvanised steel wire cage say: 4' x 4' x 2' (HWD).
| They have a hinged lid and you fill them with stones and then
| wire the lid shut. Sounds stupidly simple, and it is but they
| have some rather useful properties. Each unit is an easy one man
| lift, place and fill. Once filled, each one nominally becomes a
| large single block with great drainage properties. You can wire
| these things together into long rows. They work very well with
| water courses because they are easy to fix in place and once
| filled, won't move. Pouring conc. into formwork is a right old
| pain in a fast flowing river and it is all too easy to lose the
| finer particulates before the stuff has gone off (set and cured).
|
| You can finish the exposed surfaces in various ways. You can pour
| soil on top and grass them, pour a bit of low grade conc and
| gravel for a solid "path". The cages are not particularly pretty
| but neither are they particularly ugly.
|
| If a single cell fails then it generally won't cause much
| surrounding failure and is easy to replace or repair. You can
| embed fancy anchors inside them if you have a lateral thrust to
| resist that can't be dealt with by sheer mass.
|
| Sleepers and the like are quite convenient but you must consider
| drainage otherwise they will rot within a few decades. Block
| backed brickwork needs a decent brickie to lay them and if they
| fail it is usually rather bad. I'm no brickie but I've just
| repaired a broken 3' retaining wall at home and it looks a bit
| shit. I will be hiring a professional to sort it all out in
| spring. Here a gabion wall is overkill!
|
| I did say home projects above but these things are used
| everywhere and that includes some pretty huge retaining
| structures. If you are not a Civil Engineer and need to build a
| decent sized retaining structure then I highly recommend that you
| consider gabions first because you are far more likely to get it
| right first time.
| Arainach wrote:
| This is a decent very high-level approach, but doesn't go into
| the practical applications for most people. If you're a civilian
| looking at small to moderate-sized retaining walls on your
| personal property (4 feet or less in height) rather than a civil
| engineer designing massive projects for infrastructure, your
| retaining walls are almost certainly failing due to issues with
| drainage (not enough drainage material, incorrect drainage
| material) or _possibly_ a heavy surcharge rather than the forces
| described here.
| NikolaeVarius wrote:
| Difference from an engineer. Anyone can make a thing, it takes
| an engineer to make a thing with minimal cost.
| jeffbee wrote:
| Way I heard it as an undergrad in mechanical engineering is
| anyone can make a bridge that stands up but only an engineer
| can make a bridge that barely stands up.
| LegitShady wrote:
| factor of safety on a typical bridge 2.5, so not really.
| adrianmonk wrote:
| Then modify it to "only an engineer can make a bridge
| with a safety factor of barely 2.5".
| SECProto wrote:
| > If you're a civilian looking at small to moderate-sized
| retaining walls on your personal property (4 feet or less in
| height) rather than a civil engineer designing massive projects
| for infrastructure, your retaining walls are almost certainly
| failing due to issues with drainage (not enough drainage
| material, incorrect drainage material) or possibly a heavy
| surcharge rather than the forces described here.
|
| These exact topics are covered in paragraphs 12, 13, and 14,
| respectively. 9:14 to 10:41 in the video
| 60secz wrote:
| Had to double check the logo to understand why I was reading this
| article in Grady's voice.
| culebron21 wrote:
| The beginning of the article sounds so modernist mid-20 century,
| I couldn't stand that.
|
| Old roads that formed on old paths are much more stable because
| people went where the area was dry, and then dirt roads were
| stable and didn't move down or cause rain erosion. The
| generalizing phrase, that terrain is just an obstacle that should
| be plowed through, is laughable. People lived very well without
| retaining walls and without such huge excavations, until
| transport engineers decided to please cars, and not slow them
| down, or not make them go too steeply.
|
| Same for the sentence about buildings. There are plenty places
| where slopes are taken adavtage of. In Stockholm, there are some
| houses that have +2 storeys on one side, and entrances to 3
| storeys from different sides. In my town, a mall built in 1960s
| has 2 storeys, the top one can be entered without steps at all.
| In Finland, they used sloped ground to build stadiums, and even
| to make basements with windows.
|
| People like parks with slopes, children like to ride sleighs in
| winter on them. The most stupid thing you can do near housing is
| a flat surface and a concrete retaining wall. That generates more
| problems than benefits: the wall may float, it may create new
| concentraded areas of water running on the surface, and mini-
| waterfalls in rains. This never happens with natural slopes,
| because with grass they're very stable at 3-10 degrees, unless
| you concentrate water runoff on them.
|
| Finally, the place becomes completely uncomfortable to stay at.
| It's pretty normal to lay down on a grass on a slope. But
| unthinkable if there's a retaining wall above you.
|
| Unfortunately, nowadays I see the architects and clients prefer
| not to think and adapt to terrain, but just bulldoze the ground.
|
| Otherwise, yes, there are engineering solutions to making
| retaining walls and making them stable.
| creato wrote:
| There are more people now, and more people means pushing into
| more marginal areas. And, I'm sure people built roads that sank
| and eroded in the past too, they just aren't around any more.
|
| Personally, I care a _lot_ more about hills when I 'm riding a
| bike or walking. When I'm driving a car, hills don't matter.
|
| At the same time, building on slopes can be problematic. It
| depends on the local geology whether it is possible to do that
| or not.
|
| FWIW, I'm a bit tired of "cranky old guy thinks everyone else
| is an idiot" posts on HN.
| mitchdoogle wrote:
| A slope at a park is nice for the occasional sled, but slopes
| aren't that great when you're trying to play organized sports,
| or if you want to set up temporary structures or host events at
| your park (kind of difficult to set up a tent at an angle).
| Other than natural areas, such as national parks or forests,
| these are the primary reasons I have been to parks in recent
| years.
| cf100clunk wrote:
| The Proctor Compaction Test and its related procedures are
| absolutely vital to understanding retaining wall capabilities.
| The article oddly seems to miss such an essential cornerstone of
| geotechnical engineering. Does an amateur need to know about the
| Proctor when doing a low retaining wall at home? No, of course
| not. Does a website called "Practical Engineering" get to miss
| out on such a fundamental design prerequisite? Not IMHO. Great
| article and video, nonetheless.
| mitchdoogle wrote:
| Hopefully nobody is watching the video as part of their
| training for building an actual retaining wall. It's just
| information for the curious.
| throwaway0a5e wrote:
| For thousands of years retaining walls were successfully
| constructed without more than a cursory understanding of soil
| compaction and they didn't have rebar or geotextile to help
| them.
|
| Nobody needs to understand soil compaction if they're willing
| to move and expend way more material than the bare minimum in
| order to solve the the problem. This is true in a lot of
| subject areas. You don't need to understand a lot of things if
| you're willing to copy what is tried and true and can tolerate
| some inefficiency.
|
| For almost all personal and commercial projects the material is
| going to be cheaper than paying a real engineer to poke the
| soil with a calibrated poker and plugging the numbers into a
| spreadsheet that has some formulas.
| pixl97 wrote:
| And for thousands of years they've either been massively over
| engineered, hence the expense made them out of reach for most
| people and applications.
|
| Inefficiency doesnt work in packed urban environments that
| require to fit in a budget.
| [deleted]
| SECProto wrote:
| I think they are vital to _calculating_ retaining wall
| capabilities. But not vital to understanding them. Source: have
| spent many a day doing proctors.
| cf100clunk wrote:
| > have spent many a day doing proctors.
|
| I salute you. My late father-in-law was a slide rule wrangler
| of a pipeline engineer who often did the same. By the time I
| got started in geotech computing support (Unix, Apollo
| Domain, VMS) we had the numbers stuff readily available on a
| CRT screen for guys like him.
| idealmedtech wrote:
| I think the point of this blog and YouTube channel is to make
| these concepts approachable to the lay person, and introducing
| lots of technical jargon (relevant though it may be to actual
| geotechnical engineers) is not the best way to accomplish that.
| cf100clunk wrote:
| Time to rename it from "Practical Engineering" to "Popular
| Engineering"? To me, the _Practical_ handle is significant,
| so taking a few seconds to explain why soil compaction tests
| are vital makes practical sense.
| dsshakey wrote:
| The practical in his videos probably refer to the fact that
| he always explains things in physical models. It's very
| rare to just be theory. Thus, practical engineering
| demonstrations.
| irrational wrote:
| Thank goodness for the red circle in the top image. I totally
| would have missed the collapsed retaining wall otherwise.
| Raidion wrote:
| I think this is a great article about something that I didn't
| understand. However, as feedback, what separates this from top
| tier articles is a lack of pictures and diagrams. Just adding a
| few of those to illustrate the different types of walls would
| make this content more engaging and link it to real world
| examples. I'm not likely to google "soil nail", but I'm def open
| to spending more time on your page to check out an example.
| Cerium wrote:
| This is a transcript of a YouTube video. I'm sure there are
| diagrams and visuals in the video.
| loudmax wrote:
| Grady's web site seems to be experiencing the HN hug of death
| right now, but I watched the video last night on Nebula, and
| there definitely are visuals and they definitely clarify the
| lecture. And as usual, Grady has built a practical
| demonstration of the forces and it also helps.
| loonster wrote:
| I thought the article was in a weird place. It read like a very
| long introduction. If its the first in a series, its great. If
| its a standalone article, it lacks needed depth.
| frosted-flakes wrote:
| As others have said, this is the script for a YouTube video,
| not an article. The video is right at the top of the page.
| julienchastang wrote:
| A retaining wall collapsed along US 36, the turnpike between
| Boulder and Denver, here in Colorado. Poor drainage was the
| culprit [0]
|
| [0] https://www.cpr.org/2021/08/12/us-highway-36-collapse-
| poor-d...
| programbreeding wrote:
| I watch a lot of Grady's videos and there's a comment I've always
| wanted to make but I don't leave comments on YouTube. I'm going
| to leave that comment here: it would be great if he spent more
| time going over the models that he builds and really showing what
| they're representing. Show it from different angles, show it in
| slow motion; really explain what's happening and what we're
| seeing. Note: I haven't watched this particular video yet.
|
| He clearly spends a lot of time building high quality small-scale
| versions of things to show how they work, but more often than not
| he just shows those things while the voiceover isn't actually
| talking about what's being shown. Or when he is talking about the
| thing being shown, it's a very brief comment and then he moves
| on.
|
| I love his videos, but I very often finish them and think "I
| could have learned more if he spent some more time explaining in
| detail what's happening with the model, and replaying some
| component of it several times over as he explains it in more
| detail."
| ksml wrote:
| Just want to mention that his email is on his blog, and he's
| surprisingly responsive for having such a big following. I once
| wrote him with some unrelated questions and he gave me a
| detailed response, which I really appreciated!
| spookthesunset wrote:
| I completely agree. He spends so much time and energy with
| those models only to show them for like 30 seconds.
|
| He needs a second youtube channel or something where he can
| show way more detail about these things.
|
| Every time I watch his videos I'm always left feeling kind of
| empty...
| pcmaffey wrote:
| Is the author's name really Grady Hillhouse? Surely that's a
| stage name?
| loudmax wrote:
| Grady Hillhouse does seem like an ironic name for a civil
| engineer. As far as I can tell, that is indeed his real name.
| FWIW he uses this name on his LinkedIn profile as well:
| https://www.linkedin.com/in/gradyhillhouse
|
| IMHO, Grady's YouTube channel is one of the best things on
| YouTube. He really is fantastic.
| moffkalast wrote:
| Maybe that's why he became a civil engineer!
|
| https://i.redd.it/e1u01yu0y5n11.png
| naikrovek wrote:
| Don't make fun of people's names, man. People don't usually
| choose their own names. If you're going to make fun of someone,
| make fun of something they choose to do, instead of the things
| they don't choose.
|
| I'm confident it's his real name.
| pcmaffey wrote:
| Is that making fun of his name? Or is it simply pointing out
| / wondering whether he a) chose a profession aligned with his
| given name, or b) chose a name aligned with his profession?
| handrous wrote:
| https://en.wikipedia.org/wiki/Nominative_determinism
|
| https://en.wikipedia.org/wiki/Aptronym
|
| These things just happen.
| llefoll wrote:
| You've never heard of aptronyms?
| yjftsjthsd-h wrote:
| Lots of people have never heard of X for almost any value
| of X. Even if one had, it can be surprising to encounter
| an actual case of the thing in the wild.
| irrational wrote:
| It's like wondering about the English Professor named
| William Shakespeare. Would he have become an English
| Professor is named by any other name?
|
| https://www.ratemyprofessors.com/ShowRatings.jsp?tid=188354
| adamsb6 wrote:
| Most examples of nominative determinism don't cover both
| first and last names.
|
| This is like a geologist being named Rocky Fields.
|
| And if Mr. Hillhouse has even the smallest sense of humor
| about himself I'm sure he enjoys the coincidence as well.
| at_a_remove wrote:
| I wince. As someone with a funny name, I get that a lot. "Is
| that your stage name?" "Did you pick that out yourself?"
|
| It really sucks to hear that, as well as every other oh-so-
| original joke about my name.
| gadders wrote:
| When I saw the title, I thought that Grady Hillhouse was a
| house that was in the news in the US that might have had a
| retaining wall collapse recently.
| panzagl wrote:
| The Grady Hill House? Why do you want to know about that, no
| one ever goes up there since the...incident. Say, you're not
| from around here are ya? Well, I'd stay far away from there.
| mikestew wrote:
| A good, explanatory article that could _really_ use some
| diagrams, photos, or other illustrations.
|
| _" Both mechanically stabilized earth and soil nails are
| commonly used on roadway projects, so it's easy to spot them if
| you're a regular driver."_
|
| That sentence would have made a lovely caption to the photo of
| the "easy-to-spot" soil nail that the article didn't include.
| jasode wrote:
| _> article that could really use some diagrams, photos, or
| other illustrations._
|
| The image at the top of the article is a clickable url to the
| Youtube video which has the diagrams/illustrations/etc.
|
| The page submitted to HN is really a pre-written script that
| Grady reads to narrate the video. The intended content for
| integrating visuals is really the video and not the script.
| adewinter wrote:
| It's really a transcript for the accompanying YouTube video
| (channel of the same name as the blog)
| aidenn0 wrote:
| I'd be interested in seeing diagrams of things soil nails, I'm
| having trouble visualizing them from the text description.
| SeanFerree wrote:
| Insightful article!!
| northisup wrote:
| I believe these are just referred to as "walls" as they failed
| the "retaining" portion of the exam.
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