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  1. dBasement

    I need help sourcing a piece of air-handling equipment for a sewage treatment system

    I need some kind of air valve. I need the valve to cycle through 10 different outlets from one inlet that comes from a conventional air compressor. So, it would work with air like a hydrotech valve works for water. The project is a sewage treatment plant handling flows of about 10k gpd. My...
  2. dBasement

    Waterline freezing protection

    We are to install new manholes over an existing waterline that presently has sufficient soil frost-depth. The manhole will be vented to air that can reach -30c. Since we are now losing the insulating value of the soil cover by installing the manhole, do we now need to be concerned about...
  3. dBasement

    Compaction testing report

    If the percentage of oversize varies in the field from the proctor value, it makes sense to correct the field densities. It is more labour intensive to dig up each test location and assess the percentage oversize. Most techs I know use a graph of oversize values. We also developed a quick...
  4. dBasement

    Soil Properties

    Absolutely you would. If the soil underlying the proposed foundation has insufficient strength or bearing properties that deems it unacceptable for supporting the foundation, it needs to be dug out and replaced with structural fill, that means you dig out as well as down (per above).
  5. dBasement

    Best Bed for this situation...Perimeter Trench?

    Don't put the drain down-gradient of the septic field or it will be taking on effluent from the field. Above gradient it is a good idea, and I would go one step further and line the down-side of the interceptor (side of the interceptor trench closer to the field) with a 6mil poly barrier. Make...
  6. dBasement

    failing concrete cylinders

    Probably. Cash talks. You should be compensated for the potential lessened life of the pavement. There is unlikely anything will happen in five or ten years. But a 30 year life might be reduced to 25 (just pulling a number out)
  7. dBasement

    Curing concrete w/o lime water

    It depends. If it is strictly information or for QC, then it should be fine, if it is for QA purposes, potential litigation or comparison testing, then the results can't be used. Tank temperature is more important. Was the temperature of the water monitored?
  8. dBasement

    Grouting of Prestressed Rock Anchors

    Be really careful though that there is not any intended elasticity for the anchors. I have seen marine applications (dolphins specifically) where stressing the bolt is intended to provide some elasticity. In that case, grout would defeat that purpose.
  9. dBasement

    Field permeability testing

    If it was higher permeability than I would be more inclined to question the result, but low permeability would more easily be explained by the mere over-consolidation of the deposit. I have seen gravelly till soils that have much lower permeabilites than the above numbers just due to the...
  10. dBasement

    failing concrete cylinders

    I would be pulling the trigger. It is most likely that the specs read 4000psi at 28 days, not 256 or whenever the supplier is comfortable. As a result, the concrete should be considered failed. Should it be ripped out? Probably not, but certainly either a performance bond or significant...
  11. dBasement

    Boring Log - Well Log Software

    fattdad: I have to admit that I have a real problem with that. I can understand your reasoning, but why place that burden on the local consultants? There is lots of available software out there (we use Golden Strater for instance). I have a problem with government agencies in essence...
  12. dBasement

    Determining sand density at depth in a borehole

    f-d...I'm really not certain. The request came down from significantly higher up the food chain. My only additional information is that it is related to the hydrogeology on the site and that SPT information is insufficient. It wouldn't be appropriate to discuss more of the particulars on an...
  13. dBasement

    Determining sand density at depth in a borehole

    Thanks Mike. By California sampler, I am thinking a large-diameter SPT sampler? I agree and and am going to source a mud rotary rig. The o-rings I assume are to seal up the tip of the sampler. Would you just use the weight of soil recovered and the measured volume of the sampler to determine...
  14. dBasement

    Determining sand density at depth in a borehole

    Does anyone have a methodology for determining the density of non-cohesive sand at a depth up to 50m? There will be groundwater. I am considering either a hollow stem auger or sonic drilling apparatus and drilling to just above the test zone. I would then need to either use a clamshell or...
  15. dBasement

    Atterberg Test

    The biggest problem I've encountered with doing and reviewing Atterbergs (and I have done many) is that the tech is not really diligent about making sure that ALL of the material that is chosen for the test that CAN be broken down IS broken down for the test. What happens is, the tech gets...
  16. dBasement

    Field Density Test after 6 Months

    He said compacted subbase, so I assumed granular. I agree that all the rules change with expansive soils.
  17. dBasement

    Mohr Coulomb 3d tunneling: uplift issue

    I think your density value is off by a power of 10. Even 2500 kg/m3 sounds high for a non-cohesive material. Sorry, I know nothing about the rest of your question.
  18. dBasement

    Field Density Test after 6 Months

    Just keep in mind that the dry density won't change, but the moisture content will be a long way from optimum, so if there is any need for recompaction, you will need to get that moisture content back to the optimum range.
  19. dBasement

    Particle size distribution

    Does your method include this?: After the hydro test is complete, reshake the cylinder and wash everything through a 0.075mm wash and dry sieve the remaining sample. If so, just use the numbers from your dry sieve for the sizes greater than 0.075mm.
  20. dBasement

    Identifying Fill

    Good discussion. In addition to the items noted above, a couple of other means I have employed: Any twigs, roots, rootlets found in the matrix should be carefully examined. Are they broken? Are they characteristically sized according to where they would be if grown from a nearby tree...

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