Self Compacting Soil (#57 stone)
Self Compacting Soil (#57 stone)
(OP)
We specify self compacting soil (#57 normally) at the back of the retaining walls. Does it mean, we do not have to compact at all? BTW, I am structural engineer. Please help.





RE: Self Compacting Soil (#57 stone)
RE: Self Compacting Soil (#57 stone)
RE: Self Compacting Soil (#57 stone)
RE: Self Compacting Soil (#57 stone)
see this (it has a little exercise i ran in our lab on #57 stone just to prove the concept)
http://www
RE: Self Compacting Soil (#57 stone)
f-d
¡papá gordo ain't no madre flaca!
RE: Self Compacting Soil (#57 stone)
Flowable fill will self compact to some degree, concrete will also self compact, after placement gravity takes over and continues the compaction process whilst the concrete is still plastic.
Theoretically a perfectly rounded single-sized material could be considered self compacting. For instance, if you tip a bag of marbles into a mould they will immediately align themselves into their densest possible configuration.
Soils and gravels require moisture and compactive effort to achieve their densest state.
Of course any soil will consolidate over time but that process is due to water ingress and overburden pressure which is basically the same as the compactive process.
To my way of thinking, in construction, any soil placed in any situation should be well compacted when it is placed.
Cheers
Michael
RE: Self Compacting Soil (#57 stone)
A good way of compacting soil without imparting pressures behind the wall is to inundate the soil with water. When it drains it will be nice and compact. Provided it is decent quality granular fill , lightly compacted, say with back of excavator bucket or 1 or 2 passes of whacker plate, then settlements will be minimal. But don't rely on it for supporting road pavement etc.
RE: Self Compacting Soil (#57 stone)
RE: Self Compacting Soil (#57 stone)
I would suggest that the wall needs to be properly designed to handle the "lateral pressures" which will imparted by the backfill. That lateral pressure should be estimated by the engineer that is specifying the type of backfill material and compaction methods. If that process is followed, then the lateral pressures experienced by the wall should not be "excessive". Given that #57 crushed rock is being specified, generally only light compaction is necessary to achieve a dense backfill. In my opinion, the combination of crushed gravel and light compaction should not result in very high lateral pressures.
RE: Self Compacting Soil (#57 stone)
RE: Self Compacting Soil (#57 stone)
Also jetting while good for sands subject to PEInc's caveats, crushed stone is generally too coarse and well drained to jet. In general, crushed stone will have better lateral strength than the soil it is replacing.