Estimation of Pre-Consolidation Pressure

[Reddevils]

All,

I am doing some settlement analysis and trying to calculate the preconsolidation pressure (to check if the soil is over consolidated). I found typical pre-consolidation margin values in Coduto's book, however unable to get some kind of formulas to estimate it.

I came through google and unable to find the empirical co-relation between preconsolidation pressure with other soil parameters. But, unable to do so. If you guys have any idea, can you please share it?

Thank you in advance.

 

[oldestguy]

Here is a photo of a page in may old NAVAC manuals. It also may be on the internet.

 

[Reddevils]

Thank you so much.

 

[BigH]

Thanks for the refresh of that chart, Oldestguy. Had forgotten it was there. the NAVAC manuals are a great resource.

Another way to estimate the preconsolidation pressure if you have a handle on your undrained shear strength is to use the relationship, effective O/B pressure = Undrained shear strength divided by 0.22 to 0.25 . . . many use 0.23 (see Terzaghi, Peck and Mesri. Knowing the this effective O/B pressure and your existing effective O/B pressure, you can determine the overconsolidation ratio.

 

[BigHarvey]

An interesting article (in french, sorry !) on the subject. I'm sure BigH will love it !

 

[BigH]

BigHarvey - no problem in French . . . I have a colleague here working on the dam with me who is from Quebec . . .!