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@BigH Strangely enough, the CBR test at 100% is 17 and for 95%, 8.9, which seems to be rather high? I'm now a bit curious on how the material will behave. Interesting idea on laying PVD's horizontally!

Hi, The client wants to use a MH (USCS classification) type material for an embankment. 99% of the material is silt/clay. LL is 78%, PL is 54%. MDD for modified proctor test is only 1.22g/cm3 with a OMC = 41%. The embankment is going to be constructed on soft soils, so there will be wick drains...

@BigH We will have non woven geotextiles for drainage of induced porewater pressures. We also have a sand blanket at the ground surface to drain out all the water. At least in the FEM analysis, the walls remained vertical however there was still quite some horizontal deformation of the...

@IRstuff Will the stuff still work if it acts as the anode and cathode in an electrochemical cell where the water has all sorts of ions? @1gibson It really needs to have continuous conductivity since we want to setup an uniform electrochemical current through the soil. Also, it would be best...

@1gibson, I can't have much insulation as I want very good conductivity to setup a electrochemical current through the soil. I need the "metal" to be covered by something inert (but still quite conductive) so that the metal doesn't just corrode away and reduce the system's conductivity.

@Pud Thanks for the info, I guess using metal with a protective layer of graphite would, for now be the best option. What do you think of using that?

The reason why I'm concerned with lateral displacements is that there are adjacent properties to the site and I need to be able to roughly assess the impact on these properties (to avoid cracking other people's houses). The temporary wall heights will range from 4m-10m and we might need to...

@RFreund I'm currently using Plaxis for the modeling. I modeled the soil within the settling area (where drains are installed) as "drained" using the Soft Soil Model and the soil outside the area as undrained, using the Hardening Soil Model. However, modeling is one thing, and what happens in...

Hi IRStuff Yes, sorry I am indeed "slinging mud" to see if anything sticks. This is more as a side interest of mine to think about solutions to implement cost-effective electro-osmosis ground improvement for clays, which normally requires millions of metres of prefabricated vertical drains...

I'm designing a near-vertical temporary reinforced soil wall, to be designed to settle by using prefabricated vertical drains. The temporary FOS against slip surface failure is designed to be around 1.3. Using finite element analysis, the lateral displacements at the wall toe are about 40% of my...

@IRStuff and btrueblood What about conductive polymers or graphite? Most metals would be too expensive. This has to be installed in many millions of meters, so the unit cost is particularly important. A higher resistivity would be acceptable as well, as long as it is inert and does the job.

Sorry about the confusion. Let's say about 3A, and a resistivity less than 10^-6. What would be the suitable materials (again, they have to be inert as they have to behave as both anodes and cathodes)

@ IRstuff Thanks for the reply. This is to be combined with geosynthetics to set up a current passing through soil for soil improvement, hence it needs to be inert. Most metals wouldn't fit the bill as they would undergo corrosion and contaminate the soil. Best would be some material that can...

Hi, I'm currently looking for an flexible, inert and electrically conductive material that can be mass produced. Cost would be the largest issue here. I'm thinking of either electrically conductive plastics or graphite strips. Would like some advice on this. Thank you!

@oldestguy The lack of space is due to a public road which is next to the site. However, this embankment is going to be offset some distance away from the public road, with the rest of the permanent embankment being constructed at a later stage, supported by settlement reducing piles. We...

Hi all, For some reason, the client is unwilling to use cohesionless backfill for a temporary reinforced earth wall (using wraparounds) for the edge of an embankment fill. So far, they are proposing the use of MH type soils. I'm concerned about the problems that using cohesive fill might cause...

From what I know, there's two distinct methods of designing for earthquake resistance, one for underground structures and one for above-ground structures. For underground structures you look at the soil displacement during the earthquake and assume that the soil "imposes" the displacement on...

@rilxouss. Yes, I agree that it would be easier to directly measure the shear strength either with a vane or a cone, but for some reason, some jobs have SPT sampling with only extensive index testing and limited triaxial testing. In many textbooks they mention that the undrained shear...

Has anyone tried to correlate clay undrained shear strength with basic index properties such as water content, LL, PL, overburden stress, etc...? How successful would that be?

@dgillette This is the approach that I'm currently using. What representative value of S would you recommend, perhaps about 0.23? Do we have literature to adapt SHANSEP to residual volcanic soils? I always wondered why the undrained shear strength of a clay wasn't plotted against the void...