Depth of Borehole
Depth of Borehole
(OP)
There are two silos with a distance of 10 ft. The silo diameter is B=40 ft and the foundation pressure from silo is just under 3000 psf. Two boreholes have been decided. I am advising on the depth for field investigation. It seems the site is mainly on clayey soils.
I appreciate a feedback if a depth of 40to 50 ft suffice instead of 2B = 80 ft. Thank you.
I appreciate a feedback if a depth of 40to 50 ft suffice instead of 2B = 80 ft. Thank you.





RE: Depth of Borehole
RE: Depth of Borehole
RE: Depth of Borehole
RE: Depth of Borehole
Now that is out of the way - you should always be prepared to adjust your programme and hole depths. Obviously, if you run into bedrock at 50 ft, you would core 10 ft (to prove bedrock and not a boulder - and do at least 10 ft. A geo firm in Toronto starting with a "Gol. . ." did 5 ft one time and it was ledge rock and not bedrock - oops. Similarly, you may find a reason to go deeper. Now, having said that your programme should be flexible enough to adjust borehole depths, you should also be wanting to adjust your sampling intervals and sample retrievals. When I was in India, we had 6 m of very soft clay (Su < 20 kPa); the typical borehole would be top take a sample at 1.5 m (SPT),3 m (thin walled tube), 4.5 m (SPT) and at 6 m (thin-walled tube). I thought this was ridiculous given that we would only have 3 samples in the strata that was the most important. I adjusted the investigation to take a thin walled tube at 1 m intervals (100 mm diameter tube) and then, do a split spoon down the thin-walled tube hole. This way, while, yes, the SPT might be argued to yield "bad" results, I did end up with 6 thin-walled tubes and 6 blow counts with a chance to look immediately as per any laminations within the soil on opening up the split spoon.
Oh, and be careful of desiccated crusts.
RE: Depth of Borehole
I wonder if depth to 20% stress which is ~1.5 B (Bousinesque)is taken for borehole depth that would suffice. Otherwise the client seems to have another engineer on board who has recommended a lower depth.
RE: Depth of Borehole
f-d
ípapß gordo ainÆt no madre flaca!
RE: Depth of Borehole
RE: Depth of Borehole
RE: Depth of Borehole
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