I wonder if the holes are just becoming oversized because of the granular soils and the drilling method. Does it look like an excessive amount of cuttings are coming out of the holes? If that is happening, all this loss of ground could lead to subsidence at the ground surface, or of nearby...
Why not do a pavement design using the AASHTO method to calculate the required gravel thickness? You will need the CBR value, the ESALS (you can calculate knowing the number of trucks per day), as well as some other factors. Also make sure the owner knows that the gravel pavement will require...
Sounds like pretty heavy loads for fill (50 psi=7200 psf) and strict settlement criteria. What structures will be supported by this rock fill? Full scale load testing and settlement monitoring would be a good start. I don't know if your loading/settlement criteria is achievable with shallow...
I have wrestled with this same question- what is the depth of gravel required below a retaining wall footing to effectively increase its sliding resistance. As stated above, if there is only a thin layer of gravel the sliding forces are simply transferred to the underlying soil. I have not...
What about the nuke gauge operators? In my experience, incorrect proctor selection is more responsible for bad compaction test results than the nuke data. How many times have you heard a technician say they used curve X because the numbers seemed reasonable, and make no mention of soil type?
The DMT is a valuable tool, depending on the soil conditions. It works well in sands, silts, and clays, as long as they aren't too dense/hard to push the blade. It is no good for rocky or gravelly materials. The DMT gives modulus info, and undrained shear strength. I like it better than the...
I'm still not sure why you need to interpret this data. Is someone challenging the effectiveness of the ground improvement program? We typically just have a performance spec (i.e. bearing and settlement criteria) for the design-build contractor. And the contractor generally does a load test...
Yes, geopiers can be effective below the water table, depending on the soil type. However, keep in mind that the presence of water makes construction is more difficult- casing the holes will likely be needed and open graded stone backfill is necessary.
Geopiers don't really "take" lateral...
Mazzman- do you really think "public safety" is at stake here? My guess is that a poor geotech could result in excessive settlement and building cracks, but not some kind of collapse that would endanger public safety. Civilperson has a good point, what recommendations or judgments of the...
Let's not get too excited here. Obvoiusly what this guy did is below the normal standard of care. But consider what's being built- a one story wood frame building. In my area those are built all the time without any geotechnical. And if the soils are typical residual soils the geotechnical...
What's the real issue here? Do you just want to know the "clay content?" If so, run a hydrometer. But it sounds like you are trying to derive some shear strength parameters. If that's the case then we can't answer your question on this forum without a lot more information. But ignoring any...
Is the first floor a ground supported slab? If so, you should probably compact the fill so that it can provide adequate slab support.
Also, I'm sure you realize that the wall will have lateral pressure on it after the floor slab is in place, and that those at-rest pressures will be higher than...
How is a 6ft (2.0 m) undercut going to help with the area load from a 75 ft diameter tank, expecially when you don't know how deep the fill is, or what it is like below the depth you explored (only 3 m)? Depending on the depth of fill dynamic compaction could work. I don't think that...
The "boulder" wall that you are describing sounds like a gravity wall and normally these walls are sized so that geogrids are not necessary. The walls that utilize geogrid reinforcement generally use blocks that are specifically manufactured for that purpose, such as Keystone, Redi Rock, etc.
Compaction should have little affect on whether ko or ka is applicable. Compaction results in increased density of the backfill, along with increased shear strength. You can have some direct shear or triaxial tests run on samples remolded to varying degrees of compaction to see this...
Scienceguy57, something doesn't add up with your nuke gauge readings. DD=88 pcf, moisture=8-10% and WD=118-125 pcf? In my experience even when the nuke gauge moisture content reading is off, the moisture density relationships (i.e. WD=DD(1+M)) still hold true. If the gauge was reading an...
