saturation the dry sand for triaxial test

[avirut]

Hello,

Let say, I have been carried out a triaxial test in sand.
I have prepared the dry sand and applied the back pressure for saturation the sample. I applied the cell pressure and back pressure with 10 kPa diffrence, i.e. 100/90 kpa, 200/190 kPa, and so on.
However, I already applied the back pressure of 490 kPa but the B value is only 0.60. I am wondering ifthere is something wrong.
Do any one have any comment or suggestion to saturate the dry san. in triaxial cell.

Awaiting for comment.

 

[eline123]

I think that for soil with low compressibility coefficient (cd< 0.145e-04) where the squeleton of the soil is rigid, you won't be able to reach a B value superior than 0.69 for a Sr of even 99.5%. (see Black and Lee, 1983)

 

[avirut]

Thank eline123.
I have also found some similar argument in Head Vol.3

 

[rtcjmp]

Percolate the sample with water using a low vacuum, make sure you are using deaired water. I run these frequently and never have a problem geting a B value of 0.95 for backpressures less than 80 psi (550 kPa).

If this does not work read Nader and Clough (1985), "new proc. for saturating sand specimens" JGE Vol 110, NO. 9. This method works great