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Recent content by casimmons

  1. casimmons

    Grouted Tie-backs in Soil for a Sheet Pile Retaining Wall

    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...
  2. casimmons

    Crushed stone turnaround area

    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...
  3. casimmons

    Shoring removal and compaction

    Why not just use some type of MSE wall? It would be left in place when the other half of the fill is constructed.
  4. casimmons

    Long Term Deformation Rockfill

    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...
  5. casimmons

    Calculating Friction Factor

    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...
  6. casimmons

    nuclear density gauges are not accurate

    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?
  7. casimmons

    DMT

    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...
  8. casimmons

    Density Tests

    wet density = dry density x (1+moisture content) with moisture content as a decimal
  9. casimmons

    Interpretation of Vibro-replacement Stone Column data

    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...
  10. casimmons

    Boundary conditions

    or you can use ground/rock anchors to resist uplift.
  11. casimmons

    Geopiers thread261-64135

    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...
  12. casimmons

    Standard Practice- Subsurface Exploration

    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...
  13. casimmons

    Standard Practice- Subsurface Exploration

    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...
  14. casimmons

    NP Non Plastic Soil Designation

    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...
  15. casimmons

    Temporary Retaining Wall

    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...

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