What Liquefaction Screening Assessment Methods Are People Using?

[KVgeo]

Just trying to get an idea of what the industry is using at the moment.

Boulanger and Idriss (2008)

Seed et al (2003)

or something new...

 

[msucog]

Seed et al

 

[dgillette]

By "Boulanger and Idriss 2008" you mean the EERI red book? I think it's going to be the way of the world soon. I have some doubts about their treatment of residual undrained shear strength, but the rest, as far as I can tell, is about as good as it can be with the present state of knowledge.

 

[Mccoy]

Good reference dgillette, I know the 2004 Boulanger & Idriss and idriss & Boulanger review articles and they are darn good.

Going to order the EERI book as a personal Christmas gift to myself [santa2]

 

[dgillette]

Books and wine for gifts:

You don't have to worry about whether they are the right size for the recipient.

You don't have to worry about whether they like the color, or whether it goes properly with their decor or their other clothing.

Nobody ever says "Ohhh, I already have a bottle of wine. I don't want another one." (This is somewhat of a risk with a book, however, except when giving it to yourself.)

You don't have to worry about them going out of fashion soon, unlike neckties and purses.

If you put one on the shelf and forget about it for a few years, you may come back, open it up, and find that it is full of some very good stuff you had forgotten about.

 

[KVgeo]

dgillette,

Yes I mean the EERI book.

For the most part the book is just a summary of previous papers on the subject.

I do have several issues with it regarding sections on calculating CSR i.e. recommendations for using site specific dynamic response analyses for deep profiles with no discussion regarding the methods used by B&I to calculate the CSRs used in their CSR CRR relationships.

And the treatment of fines corrections for CPTs I think is bit haphazard and doesnt take into account the significant effect of compressibility especially with silty angular soils (i.e. tailings).

Mccoy,

I just bought Zienkiewics' et al. book on Computational Geomechanics for myself for christmas. Hell of a read. Lucky I live in Canada where there is nothing better to do in winter.

KVgeo

 

[dgillette]

I'm convinced that for their CPT relationship, you need a site-specific fines correlation. Otherwise, you need to infer fines content here from that drill hole way over there. The CPT software probably produces Robertson's Ic anyway, so it may be possible to correlate Ic or some related parameter with the actual fines at the CPTs with companion drill holes, then use it to estimate thge fines content to use for the CPT holes that don't have companion drill holes. (One of the main reasons we do CPT is so we can get fast cheap data to fill in between drillholes. ) Not an optimal solution, for sure, but I'm not sure it's any worse than Robertson's way. I've never tried to do liquefaction assessment of tailings, so I didn't think about compressibility issue you bring up. Have you ever compared IB results with Robertson results?

Interestingly, for residual undrained shear strengths from CPT, Olson and Stark's data show practically no effect of fines at all. There may be different mechanisms involved, however. One of the more important dots on the plots is Mochi-Koshi gold tailings. Wonder how compressibility might have affected that.

To the best of my knowledge, they used Idriss's magnitude-dependent Cn (1999?) to get the CSRs to develop the triggering curves.

DRG