Horizontal Consolidation
Horizontal Consolidation
(OP)
Is there any standard test to determine the coefficient of horizontal consolidation? I am assuming Cv = Ch. Is this reasonable.
Thank you.
Thank you.
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Horizontal Consolidation
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Horizontal ConsolidationHorizontal Consolidation(OP)
Is there any standard test to determine the coefficient of horizontal consolidation? I am assuming Cv = Ch. Is this reasonable.
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RE: Horizontal Consolidation
f-d
¡papá gordo ain't no madre flaca!
RE: Horizontal Consolidation
RE: Horizontal Consolidation
You can test a 90-degree sample, and you will probably find that it is substantially higher than Cv of a normal sample, but how do you use that? For typical consolidation analyses, we pretend that perfect drainage (zero excess PWP boundary condition) is provided by more pervious layers above and/or below the soft clay. What is the analogous boundary condition for horizontal consolidation?
Or, is the OP referring to vertical consolidation with radial drainage to sand drains or wick drains?
RE: Horizontal Consolidation
dgillette, Ch - coefficient of consolidation for horizontal drainage
fattad, I agree with your point
BigH, I don't think 90-degree turned sample really measures Ch. If you think about the forces acting on this sample:
Sigma(h) - vertically (i.e. on the horizontal face)
k0.Sigma(h) - radially (i.e. on the vertical face) instead of Sigma(v).
RE: Horizontal Consolidation
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RE: Horizontal Consolidation
Now if you need a value for Ch it means than you have to design a vertical drain grid. Ch can vary from 1.5 to more than 10 times Cv. Usually between 5 to 10. The more the soil is layered ( with sandy layers for example, the bigger the coefficient ). You must keep in mind that you start from a Cv value which itself is questionnable !
from my point of view, I "guesstimate" the coefficient from the geological description of the borehole logs and the confidence I have in the Cv value given to me.
The most important aspect you should keep in mind is the economics behind it. Vertical drains are cheap : check both designs with Ch = 5 Cv and Ch = 10 Cv and you will see that the extra money is generally not work the risk unless you are not in a hurry ( but who isn't nowadays !
RE: Horizontal Consolidation
For in-situ test,CPTU with dissipation test is a good and convenient way to do that.The interpretation approach could refer to http:
RE: Horizontal Consolidation
I can recall only a few jobs where the time-settlement prediction followed what the lab tests would compute out to.
Most times, the jobs settled much more rapidly than predicted.
A few jobs had a "test surcharge" to give a notion as to what to expect. Past experience in nearby sites also helped.
RE: Horizontal Consolidation
With Asaoka's method, you will have an accurate prediction of the consolidation times after a few weeks of surcharge.
RE: Horizontal Consolidation