Uhhhhh.... UHHHHH...
We swapped dams for geophysics in the intro engineering course this term, but I am severely tempted to shove “Why is a dam on QUICK CLAY a terrible idea?” on the final.
We swapped dams for geophysics in the intro engineering course this term, but I am severely tempted to shove “Why is a dam on QUICK CLAY a terrible idea?” on the final.
Quick clays are deposited in marine environments, which means they incorporate salts to create a fragile cardhouse structure.
Add fresh water, and... it all collapses.
Add fresh water, and... it all collapses.
Quick clay is extremely sensitive. You mess with it & it falls apart.
You know what triggered the Rissa, Norway quick clay landslide? The weight of a freaking tiny 700m3 earth dam.
Details: & issmge.org/uploads/public…
You know what triggered the Rissa, Norway quick clay landslide? The weight of a freaking tiny 700m3 earth dam.
Details: & issmge.org/uploads/public…
I’m trying to walk away especially as I’m not spying a mitigation plan to read, but just... why?! Why build an enormous megadam on material known to fluidize if you add weight or water?!
How is this a good idea?
How is this a good idea?
My engineering students are probably sick of my constant refrain of “and then it breaks, everybody dies, you get sued, & you never get to work again.”
But this is why!
Certified engineers must be signing off on this project. They must think this is a good idea, but how?!
But this is why!
Certified engineers must be signing off on this project. They must think this is a good idea, but how?!
Oh no. This really, really wants to be a final exam question. (It won’t be, but it should be.)
Here’s a run-down in conflicting professional opinions on the project, which doesn’t address the quick clay at ALL: cbc.ca/news/canada/ne…
Here’s a run-down in conflicting professional opinions on the project, which doesn’t address the quick clay at ALL: cbc.ca/news/canada/ne…
A huge chunk of engineering (or disasters tbh) is about managing uncertainties in decision making.
Figure out where & what types of uncertainties you have, limit them as best as feasible, & design to accommodate.
We deal with human, geologic, parameter, & model uncertainty.
Figure out where & what types of uncertainties you have, limit them as best as feasible, & design to accommodate.
We deal with human, geologic, parameter, & model uncertainty.
Human uncertainty: judgement, measurement error, mistakes
Geological uncertainty: reality is complicated & sometimes valleys/dykes/... hide
Parameter uncertainty: lab vs in situ properties, special/temporal variation
Model uncertainty: Our concept of history & processes is off
Geological uncertainty: reality is complicated & sometimes valleys/dykes/... hide
Parameter uncertainty: lab vs in situ properties, special/temporal variation
Model uncertainty: Our concept of history & processes is off
What type of uncertainty is in play when Expert A disagrees with Expert B, they use different assumptions, claim different material properties, and don’t list the same site formation history?
They want to build with a Factor of Safety 1.09?!?!?!?!! thetelegram.com/opinion/letter…
I... I can’t even. So much nope, no way, no how would I touch this project.
FoS=1 is just barely, critically stable, <1 is failure.
We typically build to FoS=2-3 because WE DONT WANT TO DIE.
I... I can’t even. So much nope, no way, no how would I touch this project.
FoS=1 is just barely, critically stable, <1 is failure.
We typically build to FoS=2-3 because WE DONT WANT TO DIE.
Correct answer:
E. All of the above.
Literally every type of uncertainty is going on with this project. It’s a case study of sketchiness.
E. All of the above.
Literally every type of uncertainty is going on with this project. It’s a case study of sketchiness.
Human: Experts disagreeing on professional judgement.
Geologic: Does it have quick clays? How much? Where?
Parameter: How will the soil properties change seasonally & with changing climate conditions?
Model: Did it form marine clay deposits that were subsequently uplifted?
Geologic: Does it have quick clays? How much? Where?
Parameter: How will the soil properties change seasonally & with changing climate conditions?
Model: Did it form marine clay deposits that were subsequently uplifted?
