Remolded clays strength

[Okiryu]

I did some unconfined compression tests in undisturbed and remolded highly overconsolidated clays and the remolded strenghts are much higher than the undisturbed strengths.

Properties for these clays are:

Clays: 60.5%
Silt: 32.7%
Sand: 6.8%
Gravel: 0%
Wn: 34%
LL: 67
LP: 30.4
Ip: 36.6

Results are:

qu (undisturbed) = 142 kPa
E50 (undisturbed) = 16 MPa

qu (remolded) = 223 kPa
E50 (remolded) = 24 MPa

Interesting thing is that I did also some UU triaxial tests for the undisturbed clays: c=108 kPa, phi=8. Clays were above water surface.

Clays were remolded under natural water content so it simulates 85% compaction (Modified Proctor OMC was 22.5%). I was surprised with the results. Means that these clays may perform well as engineering fill since their relative high remolded shear strenght. Assuming 1% of the fill height for settlement estimations, these clays can work well as engineering fill under structures or medium height embankments (althouhg I would use these clays only under small-light structures).

Some thing I realized: based on UU triaxial test results, qu's are similar for the undisturbed and remolded clays (so this gives me an idea about the conservatism of the unconfined compression tests).

What do you think about the results? Are any other parameters that I may need to verify if I want to use these clays as engineering fill?

Thanks !!

 

[BigH]

You should also check out Bishop's paper in the 1960 Boulder ASCE Conference . . .

 

[Okiryu]

I have been looking for those papers for that conference... appears that there are a lot of good info there...

 

[Ron]

Overconsolidated, underconsolidated, stiff, soft.....I still wouldn't use this material as structural fill.