Secondary Consolidation of Compacted Clay Fill
Secondary Consolidation of Compacted Clay Fill
(OP)
Hi. I have a proposed residential site where up to 5m of clay fill (glacial till, from various new and old stockpiles) is proposed to be compacted at 95% maximum dry density on a 300mm granular drainage layer. The houses will be piled however is long term settlement of the fill itself an issue for the roads, kerbs, patios, services etc? Thanks





RE: Secondary Consolidation of Compacted Clay Fill
RE: Secondary Consolidation of Compacted Clay Fill
What soil conditions are under the fill?
You have two considerations to make....one is settlement of the new fill. You can reduce that even more by requiring more compaction....why not 100% of the standard Proctor? Not that much more effort required assuming the moisture content can be controlled.
The second consideration is the soils underlying the fill. What is their settlement potential? If this is new fill, you are going to be adding somewhere around 1500 psf (72 kPa) to the top of the underlying soil.....how will this affect it? Is it sand? Silt? Clay? Overconsolidated or underconsolidated?
Will settlement of the fill add to downdrag on the piles?
A few things to consider.
RE: Secondary Consolidation of Compacted Clay Fill
RE: Secondary Consolidation of Compacted Clay Fill
So the real question may just be the compressibility of the fill - under the roads if compacted to 95% standard Proctor within a couple of percent of optimum, I wouldn't see 5 m of fill causing any problems with settlement over the long term within the fill itself - so the roads, kerbs, etc should be okay. If the soil is wetter than that, you should give consideration of aerating it to reduce the moisture content. There are other toys that could be used. Make sure you put in joints at 2 to 3 m for the kerbs if done by slipform kerbing machine. As for downdrag on the piles, I would think that the fill wouldn't settle sufficient for any major downdrag forces - and if the pile tip can "give" a bit, it would be less. You can look up Fellinius to see what downdrag might have/occur.
Just some thoughts - provide some details as noted in the first paragraph and you might get some better response.
RE: Secondary Consolidation of Compacted Clay Fill
RE: Secondary Consolidation of Compacted Clay Fill
RE: Secondary Consolidation of Compacted Clay Fill
RE: Secondary Consolidation of Compacted Clay Fill