Unconsolidated, unsaturated material strength

[gostillers]

Looking for suggestions on how to characterize the strength of unconsolidated, dry or moist spoil. The proposal is to construct a cut slope in a previously strip-mined area. The area was reclaimed with cast (loose) spoil. In-place density testing indicates the spoil is between 80-90% MDD. Material is generally classified as GC. Some of the material is moist, but none of it is saturated.

My previous thoughts --

(1) Effective strength from a CU test would not characterize the material as the test consolidates the material before shearing. This does not represent proposed conditions.

(2) I have been told total strength from a UU-test would not apply as the material is not saturated, although the UU could simulate the in-place density.

Anyone run into a similar situation in the past or have any suggestions to test the strength of this material? Thank you for any help you can lend.

 

[fattdad]

METHOD 1:
Take a bulk sample, recompact it to the field density and run a direct shear test on it.

METHOD 2:
Guess that the friction angle will be about 33 degrees (or so) and design a slope for 2H:1V.

f-d

¡papá gordo ain’t no madre flaca!