Variation of the coefficient of consolidation with time
Variation of the coefficient of consolidation with time
(OP)
Hello everybody,
Does anyone know anything about the variation of the coefficient of consolidation (Cv) with time (i.e. as consolidation is going on)?
My goal is to obtain a rough estimate of Cv when the consolidation process began, knowing its present value.
Has any study been performed on this question? I couldn't find anything in the literature.
Thank you for your help.
Ben
Does anyone know anything about the variation of the coefficient of consolidation (Cv) with time (i.e. as consolidation is going on)?
My goal is to obtain a rough estimate of Cv when the consolidation process began, knowing its present value.
Has any study been performed on this question? I couldn't find anything in the literature.
Thank you for your help.
Ben





RE: Variation of the coefficient of consolidation with time
I haven't ever seen an analysis where Cv was considered as a variable. Instead, for finite-strain analysis of plastic mine tailings and dredge spoil, what I have seen is skipping the whole notion of Cv and working with permeability and compressibility directly as fns of void ratio (or K as a fn of e, and e as a fn of sigma'v). If that's what you need to do, I can dig out refs. (I worked with tailings and dredge spoil in the '80s, but that stuff is all in boxes.)
What's the situation you are analyzing?
RE: Variation of the coefficient of consolidation with time
So I'm more looking for some sort of correlation between Cv(t=0) and Cv(t=t1).
RE: Variation of the coefficient of consolidation with time
Cv will change depending on stress levels, so "age" isn't really going to change Cv all that much. It will vary with stress, and possibly signifcantly in the overconsolidated versus normally consolidated region, so it's important to look at it in the context of your case.
RE: Variation of the coefficient of consolidation with time
Second, I know of no way to project a different Cv backwards in time like that. To do that, you would need to somehow obtain estimates of K and m-v at the two different times. I suppose, you could do that, in theory anyway, if you knew the original void ratio and the present values of e, K, and m-v, plus some way of relating K and m-v to void ratio, but I wouldn't recommend that as a real-world solution.
Have you thought about shoving a vibrating wire piezometer into the center of the layer to check for excess pore pressure?
RE: Variation of the coefficient of consolidation with time
RE: Variation of the coefficient of consolidation with time
RE: Variation of the coefficient of consolidation with time
The Cv values obtained from the CRS-tests are fairly constant with the effective stress (between 10^-7 and 10^-8 m2/s).
Field investigations cannot be performed anymore in this case, but I'll consider it next time.