GIS applications in Geotechnical Engineering???

[03LabGrunt]

Im Looking for information on GIS applications in Geotechnical Engineering. Ive seen a few papers written from engineers in India, but not very much from the U.S. Does anyone know of a Civil engineering firm that makes use of this technology on a regular basis?

Thank you.

 

[jdonville]

03LabGrunt,

GIS applications are not-discipline specific. GIS software may be used in the context of an investigation, but is not necessarily limited to the geotechnical side of the project.

Software that I have used to assist with previous investigations include gINT, Global Mapper (unregistered version), and Trimble's GPS Pathfinder Office. These applications do not play with each other seamlessly, so data from one application was exported and massaged to a suitable import format for the next as needed.

Other handy software includes OmniFormat and MS Paint (for converting PDF images to a raster format) and A9CAD and Bentley Redline (for converting CAD files to DXF format).

gINT, Pathfinder Office and Bentley Redline are licensed commercial products. The remainder are available to be used under Windows or other "unregistered" (but crippled) licenses.

Obviously, this was very kludgy, but it did permit me to gain insights into the spatial relationships between the conditions encountered at the borings and other information such as USGS topo, air photos, planned construction etc.

Jeff

 

[03LabGrunt]

Jdonville,

Thanks for replying. I was begining to think no one knew what I was talking about.
My next question , or actually what I originally wanted to know was, HOW can I use GIS in Geotechnical work in all it's aspects?
Hope that makes sense.
Thanks in advance.
Regards,
Labgrunt

 

[jdonville]

Labgrunt,

Let your imagination be your guide. What information do you have that's relevant? How can you arrange the data spatially in order to provide you with an insight that you couldn't otherwise get? Be creative.

I would typically use several applications to obtain layout or approximate as-drilled coordinates for borings. Overlaying these locations on USGS topo maps can help you with the interpretation of what's fill/not fill, and approximating existing/historical surface elevations (boreholes are so rarely surveyed, a fact that disappoints me to no end).

Commercial-grade GIS systems (software packages designed for easy interoperability) can be very expensive, so they're generally not cost-effective for small projects and practically unheard of for large projects unless there is a deep-pocketed government agency (or mining company) involved as an owner/client or partner. Even then, the geotech largely has no experience exploiting the information.

Fortunately, many US states and federal agencies are beginning to develop good-quality datasets that are available for low or no cost. Well records for water oil ad gas, for example. Mine subsidence maps can also be had if you dig into state websites. NRCS Soil Survey information can be had using the online viewer (maybe even downloadable, too).

MS Word and Excel are very helpful at massaging data being transferred from one application to another. You may also find Surfer (surface and mesh generation) helpful, but it's also commercial.

Jeff

 

[geonebular]

jdon has got it right. The amount of data available for free from governemnt agencies is growing quickly. My company has someone soley dedicated to crawling state, county, city websites and downloading anything she thinks we could use. ie. USGS seimic classification data. She also is constantly compiling a data set of all our geotech and CMT job sites. This way anyone in our other depts or offices can pull up an interactive map showing where we have done work and also pull up our geotech reports and lab results.

My personal opinion is gINT/PLOG and a nice handheld GPS unit/computer interface program are worth the cost versus the headache of trouble shooting 2-3 different format jumps to make everything play nice with each other.

 

[msucog]

we use the good quality garmin's (60csx and 76csx) since the units have a superior antenna that picks up whether you're under heavy canopy, the unit is in your pocket, or even if you're inside buildings (reception varies depending on you locale but is generally <20' accuracy). we also generate our own topo maps using free software which can then download the topo to the gps. we don't just follow the gps blindly but it definitely helps to confirm your location. i'm sure most of us have been in the woods looking at a quadsheet and trying to figure out which hill top you're on. the topo maps can be generated to any interval but i usually don't get tighter than 5' spacing just for onscreen clarity. plus, the reported vertical accuracy by usgs is 3m (soon to be 1m and the data is supposedly updated several times a year). you can even overlay actual site plans with the gps data points and tracks to confirm your location pretty close. i would say that a gps can easily pay for itself in one subsurface job where clearing is required. you spend say 2 hours before you go out and you could cut field time down by 4 hours. if you're spending $100/hr for clearing equipment plus engineering time it saves a lot. i have actually cut 2 days off 5 days worth of clearing/layout time before. however, we always propose jobs like we don't have this capability since i have been in a situation where the gps malfunctioned in the field or something simply didn't work so then you resort to topo maps with a compass and pacing.
we once kept track of the lat/longs of jobsites but that managed to get screwed up since when we have repeat clients, job info sheets for past jobs are used to quickly fill out new ones to input in to the system. quite often, the lat/long would not get changed so then you end up with 20 jobs at the same location. sort of our own fault or the people inputing the information and not defaulting the lat/longs to zero.
i think it would be awesome to some how compile all of our boring data to specific lat/long and have that information available. we drill hundreds of sites a year in this area so we have the potential to have a very "complete" database. it would be a very complex and complicated task, so i'm not sure how one would accomplish compiling such a database. if you started now going forward, it should be much easier since you could update it as you go. i'm sure someone out there like usgs would be very interested in the geological information that could be obtained.

 

[msucog]

oh and by the way,

http://www.REI.com

has a sale going for the garmin 60csx for $349+$50 rebate. the unit is usually almost $500.

 

[jdonville]

msucog,

Ohio DOT requires GPS survey of all test hole locations. Using a couple of hours ahead of time to setup layout waypoints is a huge time saver - especially when you're laying out hundreds of borings (we did about 390 test borings along a 22-mile segment in my last big DOT job) across corn and bean fields.

The DOT is compiling a huge library of all new test borings performed for DOT projects across the state. Northings and Eastings are reported in State Plane coordinates.

The equipment we used was a Trimble GeoXT (2003 series) handheld that permitted post-processing of collected points against CORS data for potentially submeter horizontal accuracy. Ususally this only required about 3 minutes at each boring or feature of interest.

Submeter vertical accuracy with that GPS unit takes a lot more time (by about a factor of 5 or 10) per feature, so the usual strategy is to generate a synthetic vertical ordinate based on a sitewide survey using real-time differential GPS techniques with way more expensive equipment.

The GeoXT and software cost about $4000 a few years back. I'm sure that it's fallen a bit since then with better capabilities in the newest models.

Jeff

 

[msucog]

we looked in to the trimble geoxt but it was too pricy for management and for our current demands. the garmin 60csx and 76csx has done spectacular for less than $500. we don't publish accuracies in our report, but if dot ever told us to tighten up our accuracy, we'd fork over the money. they seem fine with our current system. i would like to have the vertical accuracy you get with the trimble since i wouldn't trust elevation data on the garmin even with an altimeter and barometer. i have calibrated it to a survey state and checked out several other stakes and it came with 2' vertical accuracy...i would definitely not call that typically though. horizontal accuracy is mainly what we look for. if we need published accuracy, we'll hire a surveyor. i do like new surveying toys though.

 

[DrillManager]

We use GIS and GPS. We use coordinates from the drawing and convert them to UTM and download into Garman GPS units. Boring layout time we find in Florida is reduced by more than half. I've found borings up to a year later on a project. We are in the process of upgrading to Autocad Map3D to allow us to use all the parcel and soils map data that is available. When clearing for drill rig, we load up the points and get on the dozer and go to the point. Clear an area, then move to the next one. On a site that is 3000'x1000' with nothing but palmettos five feet high, is where you see the real savings. We also have a Leica GS20 GPS unit that we use as well for survey grade data. GPS and all the tools around it is the only way to be competitive any more.