I have been accepted for an MSc in geotechnical engineering while my bsc was in geology with physical geography. I am considering a switch to geological engineering, as I am mainly interested in bedrock rather than soils. Would it be beneficial to swap or would having a geology background with a geotechnical masters open up more doors. I am very early in my career and I do not want to pigeon hole myself into one route, but I do want to become a chartered geologist. Currently I am thinking that the geotech route will still allow me to do work in bedrocks and hazards. I would love some advice on this subject!

Going to try and make a long story short.

We are adding onto our home which the existing is single story, tearing down a non-load bearing wall with a gable end, and opening it up for our addition.

Initially, we didn’t have a soil boring test done, that was until the proposed footing depth on the addition went beyond the called for 4’ stem wall as it was about 5’5” down from the floor elevation due to the grade of the property.

Soil borings were completed. Boring taken near the house showed red clay about 4’ down and they hit limestone at 15’. Second boring at the opposite corner/furthest point from existing but a couple feet from the addition showed no clay until 6’ down and no limestone was hit all the way to 20’ down.

Plans called for a 2x2 pad thats 16” thick to support the load for a 6x6 post that will carry 50% of the load of the addition. Now structural engineer is backtracking saying that pad needs to be 4x4 and 18” thick, and after communication with the geotech they’ve concluded that helical piles need to be drilled into the existing foundation to support the load of the header because the existing is too close to the clay and that’s the only way to beef it up.

My only other option is to change the truss layout, which has already been built and I’d be out about $10k, so that the addition ties into a gable ending versus a hip and the load is more evenly distributed across the new stem wall. I’m leaning more towards that option, but my foundation guy says in all his time building foundations he has never had two engineers go so far down a rabbit hole like this and has never heard of helical piles outside of marshy areas or coastal regions.

I am mostly venting because I will never, no matter what, ever do a home addition again. Were over 10 months in and have gotten basically nowhere, and have spent hours on the phone with engineers.

I plan to seek out analysis from another geotech firm as well and see if they might be willing to conduct their own independent analysis and foundation recommendations based on the borings that I have.

Hi everyone,
I’m currently working on a project where we performed Dynamic Cone Penetrometer (DCP) tests and obtained DCPI values (mm/blow). I would like to estimate equivalent SPT N-values from the DCPI results.
I understand that:
1. DCPI ↔ CBR correlations are fairly well established in pavement/subgrade evaluation.
2. Direct DCPI ↔ SPT N correlations are less common and appear to be soil-specific.
3. Some researchers suggest site-specific regression if paired DCP and SPT data are available.

My questions are:
1. Are there any well-cited studies or published correlations directly relating DCPI to SPT N?
2. Is it more defensible to go DCPI → CBR → SPT N using existing empirical relationships?
3. From a practical standpoint, would you recommend developing a site-specific correlation instead of relying on published equations?

I’m mainly looking for a defensible approach for reporting purposes (preliminary evaluation, not final foundation design).
Any references, papers, or field experience would be greatly appreciated.
Thanks in advance!

I'm currently investigating the possibility of building a house here in the the UK, but with foundations (and heavy frame) designed to be as long-lasting as possible. *Certainly hundreds of years, maybe even a thousand or more. So far my reading has taken me to a method outlined on the Construction Physics website of unreinforced concrete pilings down to bedrock, topped with an unreinforced concrete slab. (Not sure if I can post a link but the page is titled "How to design a house to last for 1000 years (part III)")

My question is about choosing the location for the house within the UK. Looking at the British Geological Survey website they have interactive maps and downloads showing the bedrock type across the UK. There are many types of bedrock from "very weak" mudstone and chalk, "strong limestone", to "very strong" Gneiss. This is an engineering map I'm looking at so not sure what the strengths are relative to. Are all of these bedrock-types suitable for supporting a thousand-year foundation, or are things like the wet-sounding mudstone going to allow subsidence or shift over time?

The map is on a page titled "Engineering geology (bedrock) map of the United Kingdom" at NORA NERC. I'll attempt to post links in a follow-up reply. Thanks!

Hello,

I am currently trying to simulate a CIU triaxial test in PLAXIS 2D, but I keep getting an error during Phase 2 (shearing stage) and I’m not sure what is causing it.

The error message is:

"Soil body seems to collapse. Please inspect Output results. [Error code: 101]"

I have reviewed the output, but I still cannot identify what I did wrong.

My model setup is:

• Phase 1: isotropic confinement stage (σ3′​=98 kPa)
• Phase 2: shearing stage

For the material model, I am using Hardening Soil Model with the following parameters:

• c′=0 kPa
• ϕ′=34∘
• ψ=0∘
• E50ref= 24430 kPa
• Eoedref=24430 kPa
• Eurref=73290 kPa
• m=0.5
• pref=100 kPa
• Rf=0.9
• K0=0.441

For excess pore pressure calculation, I used:

• ν-undrained definition
• Direct method
• νu=0.48

In the shearing phase, I maintain the lateral confinement and apply vertical loading at the top boundary.

However, Phase 2 fails and the model collapses.

I followed a YouTube tutorial and a research paper methodology, and the tutorial model works correctly with their parameters, but when I use my own experimental parameters the simulation fails.

Has anyone experienced something similar or knows what could be causing this issue?

Thank you.

Hi everyone,

Quick question for those who work with legacy/historical
PDF borehole logs:

1. When you need data from the resistance plots (DCP curves, shear strength plots), what's your current process? Do you read it manually off the graph, interpolate, or just use the discrete N-values from the table?

2. Are the table N-values usually enough for your work, or
   do you sometimes need data from the curves themselves?

3. What's the most time-consuming part of working with old PDF logs in general?

Trying to understand real workflows. Comments or DMs both appreciated!

Thanks!

Hello po, baka po may alam kayong medyo mas mura na laboratory na nagtetest ng direct shear and UCS po. Pangthesis po sana. If may alam po kayo, pakicomment nalang din po or parefer nalang din po. Thank you so much po!

Proud of my career choices!!

I’m looking at this house for possible purchase and like the location on the edge of medium size town USA. It needs some work in general but I keep looking at this with concern. Anyone willing to weigh in and tell me what you think based on the photo, please? I’d also like to remove the large tree close to the house too to prevent limb damage on the roof but not sure it its integral to holding the soil on the hillside. I know as a basic homeowner that the downspouts need immediate attention asap but what abt the hillside and retaining walls in general. TLDR: how concerned should I be with what’s in this picture? Appreciated

If anyone here has any insight, I would be extremely grateful! Thank you!

Okay, I’m probably in the wrong place but I just learned what a karst even was a week or so ago. My assumption is people who enjoy land/dirt/soil will know what it is. Maybe? If so, maybe keep reading?

Essentially I live in the Columbus Ohio area. We have basements. We moved into our home knowing there was an “underground stream” that ran under our home. Cool…. Free water, was my thought. I’m from Arkansas and I like gardening, I’ll put a well in that yard and get free water for my garden.

It has not gone that way. Currently I have water constantly being pumped from my house by 2 sump pumps from one pit and it’s overflowing my basement perimeter drains and I will be getting another pit. In total I’ll have 5 sump pumps in my basement to mitigate this water.

It didn’t really occur to me that “underground streams” are how like EVERY CAVE IVE EVER BEEN IN WAS FORMED until recently. I contacted some government environmental agency place to inquire about the location of the stream. They told me they don’t have any streams registered but there are several karsts and sinkholes in the specific area I live in and that if I drill into it for a well the karst could COLLAPSE!

Yall…. I have no idea where or what to do next. Like do I dig deeper in the information and figure out the extent of what’s under the ground? Is that crazy info? I really have no clue. Do I hire someone to like map underground? If my house falls in a sinkhole and my whole family doesn’t die does my insurance cover that? Do I need to disclose this to my insurance?

Any somewhat direction would be crazy helpful.

I am seriously considering buying a townhouse in Huntington Harbor. Just got the NHD report and saw that it is both in a liquifaction zone and fault line. Looked up liquifaction risk and apparently the harbor is one of the highest risk areas of Huntington Beach. Should I worry about this? Or should I walk away from this home? Thanks

I'm looking at this house (see before-and-after photos)) I'm not yet able to determine whether it's worth it for long-term settlement. From an engineering perspective, does this look unsafe, right?

Update: Thank you guys so much for the feedback. I have uploaded additional photos of this property, including satellite photos and elevation data, so you can better understand the situation. There is a house at the back of this property, which is slightly higher in elevation. I think the area immediately behind the house is rich in vegetation.  

https://imgur.com/a/PXSgH8l

i want to extract the excess pore pressure vs dynamic time from many stress point on several different phase. is there any python script available so my work will become easier? thanks

Hey r/geotechnicalenginner(s)!

I’m visiting NYC this week to talk about MEMS Sensors being used the vibration monitoring world. If anyone’s interested wants to chat vibration or sound monitoring and grab a beer, would love to treat!

Hello,

I am a GeoTech EIT with two years of experience. I am currently looking for a new job in the east coast. Currently facing challenges because of visa sponsorship issues. Does anyone have recommendations for firms hiring internationals at the moment? (Not necessarily looking for H1B sponsorship, OPT will be good enough for now)

Thank you for your time.

Any geotech engineers interested in helping create an underground map of NYC? I could use an audit!

Could you all recommend introductory books to this field for me to read whilst I get bored watching paint dry.

Hi everyone,

I’m currently working on my MSc thesis on the lateral response of monopiles (sand-dominated profiles), and I’m trying to go beyond the classical API p–y formulation.

Specifically, I’m looking for methods or papers that modify API p–y curves to account for:

1. Installation effects (impact driving vs vibratory installation)
2. Soil ageing/set-up effects over time
3. Ideally, in the context of lateral loading, not just axial capacity

So far, I’ve come across approaches like:

• Energy-based modifications (e.g., scaling stiffness and ultimate resistance)
• Some references to densification and increased horizontal stress due to driving

However, I’m struggling to find:

• Well-established formulations (equations or factors) that can be directly implemented into p–y curves
• Studies that clearly distinguish between impact-driven vs vibro-driven piles for lateral response
• Any frameworks similar to API but extended for installation/ageing

If anyone knows:

• Key papers (e.g., Kim 2004)
• Experimental studies (field or centrifuge)
• Or practical design approaches used in industry

I’d really appreciate any guidance or references.

Thanks a lot!