Effect of compaction on lateral pressure.
Effect of compaction on lateral pressure.
(OP)
How does compaction of fill affect the lateral presssure on a rigid/fixed retaining wall? Besides the change in density and therefore the overall vertical pressure and change in the friction angle value, is there anything else that will affect the value of coffiecient of lateral pressure? If yes, what is the equation and where can I find it?





RE: Effect of compaction on lateral pressure.
RE: Effect of compaction on lateral pressure.
you can perform any test to check out the density of the soil. and regarding calculating the new friction angle u can preform the SPT test.
regards
Amanpreet
RE: Effect of compaction on lateral pressure.
amanpreet, I have already considered the density and friction angle factors....I am looking for a different kind of effect that leaves a residual lateral pressure even after the compacting force (or overburden)is removed (I assume that case exists).
Any more help is welcome.
RE: Effect of compaction on lateral pressure.
Ko=(1-sin(phi))+[(Gamma(d)/Gamma(dmin))-1]*5.5
where:
Gamma(d)=actual compacted dry unit weight
Gamma(dnmin)=dry unit weight of the sand in its loosest state
For clays, figure the OCR of the compacted material and multiply Ko by the square root of the OCR. If you are using clay backfill (local practice when expansive clayes is the retained material), I would limit the level of compaction only to what is needed to reduce settlement. This would result in not being over consolidated, and the above would not apply.
RE: Effect of compaction on lateral pressure.
RE: Effect of compaction on lateral pressure.
Ingold, T.S., Retaining Wall Performance During Backfilling, Journal of the Geotechnical Engineering Division, ASCE, Vol. 105, GT5, 1979.
Jeff
Jeffrey T. Donville, PE
TTL Associates, Inc.
www.ttlassoc.com
RE: Effect of compaction on lateral pressure.
RE: Effect of compaction on lateral pressure.
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RE: Effect of compaction on lateral pressure.
i cant find the reference to that figure...do u know where it came from?
RE: Effect of compaction on lateral pressure.
I drew that for answering your post, and is what I use for estimates. You can make your own chart from this older Soil Engineering by by Spangler and Handy, 4th Ed, 1982. It is on pages 564-565. Basically what they found is that the pressure induced by the rollers are double of that estimated by Boussinesq's line load stress distrubuition for the upper 4-5 feet. Below this depth it follows the Boussinesq stress line. Also Gerber found similar resultes in 1929. Try online bookstores for a copy of thie soil engineering book-4th ed.