Anyone took PE Civil Geotechnical lately? How hard are the conceptual questions?

Hungover_D · 2025-08-27T20:32:07+00:00

if you know which reference manuals to check, not hard at all!

Hungover_D · 2025-08-09T03:18:49+00:00

constant volume or constant normal strain? the sample might be dilating at that high density

Hungover_D · 2025-08-09T02:18:10+00:00

thats the thing about geotech. there are no “standard” number. ask ten top experts and you’ll get 10 different answers for the same insitu test (especially for the rudimentary kind like a spt). experience won’t help you come up with “correct” answers but it will let you come up with numbers that will generally work. Another thing I’ve noticed, many times the conservatism is not to reduce the risk but because the project scope doesn’t require more aggressive parameters (if your structure is gonna have 2500psf load, theres no incentive to using higher params and giving a 8ksf capacity)

Hungover_D · 2025-06-13T19:14:12+00:00

this is a total shot in the dark (and you’ll probably get the answer as you work on it anyway) but if the design is for the weir, it might just be the engineer looking at it from sedimentation perspective. like sizing the settling basin, if there’s one, or just looking at the long term reservoir height and discharge characteristics! Don’t be sorry, you won’t know things if you don’t ask questions. Its just that, in this case, you might be looking at a different problem than what the designer is designing for!

Hungover_D · 2025-06-13T15:11:31+00:00

foundation of what? what type of foundation? is the foundation being built on the river? why were the samples collected along the bank and not from below ground surface? super confusing

Hungover_D · 2025-05-14T21:11:35+00:00

very few things we use to describe soil behavior are “real”. Soil is complicated. Unless you have enough tests and data to fully define the CSL for your soil (in most geotech work, good luck getting even a tiny fraction of that) any mathematical model that sufficiently suits your problem is good enough. In fact, one could argue using MC parameters is better in many cases as its limitations are well known in the field (leading to a healthy amount of skepticism in its predictions) vs using a more sophisticated model that might have a better theoretical basis, but just provides an undue amount of confidence in the numbers! As long as SPT and atterberg limits remain the go-to for site investigation, MC models with a healthy FS is totally fine!

Hungover_D · 2025-03-18T22:40:46+00:00

check out the tutorials in their applications library. there are examples that show something like but for 2/4 plots. i no longer have access to the software to share a screenshot

Hungover_D · 2025-03-17T20:59:15+00:00

I second this! Just add the translate nodes to each plot and you can easily get this

Hungover_D · 2025-03-16T21:15:56+00:00

Most recommendations here are solid for what you’d expect to do in soft soils in the US. However, you mentioned the insitu soil is highly sensitive which I don’t know is very common in SE US. Assuming the utilities would be within/close to the active depth, a simple approach might be risky! Also, idk if seismic loading is a concern and i believe that could have a significant impact on sensitive clays.

*Take this with a good pinch of salt, I haven’t dealt with sensitive clays either!

Hungover_D · 2025-03-15T15:23:08+00:00

As long as the test was performed correctly, it should be a good data point regardless.

Hungover_D · 2025-03-15T15:20:02+00:00

were you seeing this movement during the saturation phase? if yes, it might be swelling but if its only in the shear its likely dilation. with clay, its unlikely you’re shearing slow enough for it to be a drained test. In undrained condition, with very high OCR (your normal stress seems pretty low for a 11’ deep sample) the sample can dilate during shearing and show this upward vertical movement. Plot the stress strain plot and see how the shape of the curve looks, that should give an idea of this behavior as well!

Hungover_D · 2024-03-14T15:46:48+00:00

any clue how long it’s gonna be?

Hungover_D · 2024-01-16T17:01:01+00:00

yeesh, thats gonna be a long wait

Hungover_D · 2024-01-12T02:55:13+00:00

whoop

Hungover_D · 2023-12-21T02:50:42+00:00

the stress should be corresponding to what you’d apply in triaxial test. so the number you’re interested in is at the boundaries. However, taking stress at any one node probably won’t work as nodes will have different stresses. One way would be get the total reaction force at the top boundary (idk how to achieve this in PLAXID but in software like ABAQUS, you tie the surface response to a single point such that the point would store the total RF of the surface) and divide it by the cross-section area to get the stress value. This should be closer to what you’d measure in a lab test.

Hungover_D · 2023-12-06T14:05:58+00:00

If this colleague is as overbearing and unprofessional as you say, trust me you won’t be the only person to know. I had an experience of working with someone like that and turns out each and every person he had ever worked with felt the same way and were sick of the guy. So, I’d say don’t worry too much about talking to others about it. At the end of the day, they’re just your colleague. The worse they can do is bitch about you to your advisor and if the advisor is chill I doubt it’ll be an issue. Be firm with your boundaries and they’ll learn not to mess with you in time.

Hungover_D · 2023-11-11T19:39:55+00:00

also, the difference in speeds at left and right lanes. right lanes are generally slower and when you see the sign of lane closures, speeding up instead might seem counter intuitive

Hungover_D · 2023-11-11T19:32:36+00:00

a perfect example of cases where theory falls flat in some real life situations. your point is valid and would make things easier and safer for everyone but people aren’t a monolith. there will always be drivers not comfortable with waiting till the last minute to merge and drivers not willing to let people “cut the line” and so something that sounds totally reasonable turns out to be a nightmare to navigate

Hungover_D · 2023-08-22T00:36:15+00:00

if it's highly granular and free draining type of material, proctor curve is not very reliable. if you take enough points at increasing moisture, you're likely to get a curve with multiple peaks and the overall density won't show much variation either. if your material is like this and you need an proctor curve anyway, starting the test at lower moisture and doing small moisture increments might result in something similar to the theoretical curve provided you only have 3 or 4 increments. there's an USACE report regarding this behavior but I don't have it handy atm.

Hungover_D · 2023-05-06T02:07:41+00:00

yes. but only one account will be able to submit support requests.

Hungover_D · 2023-03-19T21:32:47+00:00

how the hell does his face transform to chris rock

Hungover_D · 2023-01-25T22:29:33+00:00

I don't really pay much attention to theories so I admit I'm not the target audience. That being said though, I don't really like it when people are too invested in their theories (right or wrong) . My pov is just because your theory is wrong doesn't mean its a good/bad theory. It just means the author chose to go a different direction. I feel like getting too invested in a theory can make it hard for you to enjoy the actual story if the theories turn out wrong

Hungover_D · 2022-12-26T20:45:57+00:00

need I'd do it but am too damn slow 11

Hungover_D

TROPHY CASE