Modified CA sampler

[nagatalluri]

Guys:

In one of our projects in Oklahoma the geotechnical contractor conducted direct shear test (not sure if they reconstituted the soil) on the sample obtained from Modified CA sampler.

Do you think it is possible to get samples for consolidation test (without reconstituting the soil) using the modified CA sampler ?

Is it really representative sample, what we get from Modified CA sampler for engineering testing ?

Please advice

Thanks
NT

 

[Toxick]

A direct shear test on a reworked sample is NOT representative of the in situ soil. Period. Any sample from a Mod-CA sampler is disturbed and not accurately representative of in situ soil - but frequently is good enough for a direct shear test depending upon how it will be used and application of appropriate factor of safety.

Also, keep in mind that "disturbed" does not necessarily mean "weaker." A loose, granular soil can become denser due to vibration, some layers of thinly inter-bedded soils can be compacted, and any relatively loose soil can be compacted if the sampler is over-driven (100% recovery achieved by driving 110% of sampler length).

 

[nagatalluri]

Dear Toxick

Thanks a lot for the input.
I appreciate you taking time and educating me.

Naga Talluri