Saturation of Clay in Triaxial
Saturation of Clay in Triaxial
(OP)
hi everyone
I am working on a phd project where we \re using Lambeth group clay (LL 60% PL 26% OMC 19% particle density 2.7)I have collected disturbed samples from site and remolded them into 100mm dia 200mm length mould applying specific compaction effort. I am trying to saturate the sample in triaxial equipment aplaying 50kpa cell and 30 kpa back presure. I have been waiting for few days and there is no hope. Anyone has any saggestions for making saturation process faster or possible .Concern is that during compaction samples from the site chopped into 10 to 15mm small pads and brought to OMC inorder to simulate site condition. I think this is causing some discontinuitys within the sample and not allow full saturation. Any comments, new ideas can help.
Thankyou
I am working on a phd project where we \re using Lambeth group clay (LL 60% PL 26% OMC 19% particle density 2.7)I have collected disturbed samples from site and remolded them into 100mm dia 200mm length mould applying specific compaction effort. I am trying to saturate the sample in triaxial equipment aplaying 50kpa cell and 30 kpa back presure. I have been waiting for few days and there is no hope. Anyone has any saggestions for making saturation process faster or possible .Concern is that during compaction samples from the site chopped into 10 to 15mm small pads and brought to OMC inorder to simulate site condition. I think this is causing some discontinuitys within the sample and not allow full saturation. Any comments, new ideas can help.
Thankyou





RE: Saturation of Clay in Triaxial
I'd recommend that you take the bulk sample and prepare it at 90 percent saturation to the relative compaction you are interested in (this will likely be a point on the wet side of the standard Proctor curve). I'd add the water, seal the sample in a bag and let it sit for 24 hours (i.e., moisture condition the sample).
I'd compact the sample, trim it and put it into the triaxial cell.
I'd expect you'd need somewhere around 70 to 90 psi of back pressure to get all the air into solution (480 to 620 kPa). So, you're nowhere close to what you'll need.
f-d
¡papá gordo ain't no madre flaca!
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
Drained and undrained laboratory element tests will be performed on saturated samples to characterise the behaviour(Critical state soil mechanics).
We will test laboratory compacted and insitu compacted (obtained by block sampling method (undisturbed)samples. Therefore they should carry same properties. If I increase the moisture content and compact the sample the formation will not be similar to the insitu sample.
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
You should include research into the behavoir of compaction clays as strength corelations that don't account for compaction moisture content would be remiss.
f-d
¡papá gordo ain't no madre flaca!
RE: Saturation of Clay in Triaxial
Soils that was extracted from the site and sealed in plastic bags was chopped in to small pieces from 10mm to 15mm.
This was done because in-situ ped size will be too large to avoid scale effects within the triaxial apparatus.
From same bag another compaction test was carried out to obtain Optimum moisture content and Maximum dry density
(Please See attached Image for Compaction curve. please avoide the teriminology such as classic compaction and 24ht compaction they are for my use compaction curve is red one)
Once the optimum moisture content was obtained the soil in the barrel should either let to dry or moisture should be added to achieve optimum moisture content
To achieve the desired moisture content, distilled water was sprayed at intervals onto the soil over a period of several hours
This will enable the water to penetrate the granules and achieve equilibrium
Clay was moistened to 1-2% wet of their respective optimum values and sealed back into the barrel and stored in a controlled humidity room for several days
100 x 200mm compaction mould was used with specific compaction effort to prepare sample ( 5 layers 25 blows) BS 1377-4:1990
Immediately after the compaction, compacted samples were placed in highly sealed begs and stored for Triaxial tests
Then saturation problem as I mentioned above.
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
You can also try presaturating under vacuum. When the sample is in the membrane, apply a vacuum to the sample. Then run water through the sample using elevation head (<3 feet) to drive the water though.
The key is patience and high pressure.
RE: Saturation of Clay in Triaxial
Any idea on what was the cause of decrease last night and what do you think will this specimen saturate with current set-up?
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
RE: Saturation of Clay in Triaxial
http:
Please ignore this attachment its wrong figure.
Yes drain line is draining to the flask which is open to the atmosphere. Yes thats the total amount of water gone into the sample in 24 hours. Seems to me that it will take ages to saturate.
RE: Saturation of Clay in Triaxial