compaction problem.
compaction problem.
(OP)
Been doing this 26 years so no dummy here. I got this pink silty whatever, it not a sand, not a clay. It classified as a SM. its almost talcom powder. It wont get over 92% modified. I have double check nuke, sand cone ,drive tube all within a pound. double check PD. one points under nuke, still on curve.
Pd is 121 at 12 but I cant get over 110 lbs no matter what. Huge vibration steel wheel, rattle the building. 6 inch lifts. I cant figure this dirt out I can do a one point at the nuke moisture under the nuke and get 119 lb so that mean the roller should get close to 116 lbs, cant get over 110.
anybody have any ideas?
I,m flooding it right now hoping to use the water as a lubicant to get the final compaction 2 % Its not pumping and never had pump. the soil under it is white beach sand.I got about six feet of this pink
Pd is 121 at 12 but I cant get over 110 lbs no matter what. Huge vibration steel wheel, rattle the building. 6 inch lifts. I cant figure this dirt out I can do a one point at the nuke moisture under the nuke and get 119 lb so that mean the roller should get close to 116 lbs, cant get over 110.
anybody have any ideas?
I,m flooding it right now hoping to use the water as a lubicant to get the final compaction 2 % Its not pumping and never had pump. the soil under it is white beach sand.I got about six feet of this pink





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I have check three nukes today, one being an asphalt nuke, sandcone, drive tube, all withing a pound of each other. Just cant get it in the field. thinking it might need a day of wobbly wheel
RE: compaction problem.
RE: compaction problem.
A wobble wheel won't get you as far as a sheepsfoot will with this type of material.
Post your gradation...we'd be interested in seeing it. Also post one of your Proctor curves.
RE: compaction problem.
you checked the lift under the previous since you might have confinement issues with the compaction at surface.
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Sounds like economics are coming into play.
What will the embankment support?
Is the pit/cut area at the contractor's discretion/choice?
What is the avg fill height/CY to be placed?
Is stabilization possible? Or a change in borrow sources?
The experiences with silt I have encountered were not easy to work through. If I am remembering correctly...the borrow source was in close proximity to an old waterway that had been around a long long time.
I would be interested in knowing what the atterberg limits are. Also would like to know the pyramid of shots (roller/compactor passes) as this material is being placed and at what point it stops gaining.
RE: compaction problem.
The solution for the monitoring of the density of the fill was from a multiple approach, including looking at the air void content and the variation in MDD between the 2.5 (standard) and 4.5 (modified) rammers. I also used the DIN 18134 plate load test as a rapid means of assessing the abiltiy of the ground to be further compacted. If you are not familar with the test, the set-up is pretty similar to a normal plate test, but the manner of loading and the calcs are very different. The test uses a 300mm diameter plate and is loaded in 2 cycles. The first cycle has 6 loads and 3 unload stages, and the second just has the first 5 loading cycles again. For each load cycle you determine Ev, then do the Ev2/Ev1 ratio. German (DIN) guidance then provides data on the acceptable ratio for different materials and different degrees of compaction. Test only takes around 25mins as each load is kept on for a maximum time, not till all settlement stops so its very different from a lot of the other plate test methods out there.
Finally, in order to be able to compact the fill, each and every layer had to be dampled down. As the material was relatively free-draining, any wind or sun would dry the surface and you just could not compact the fill.
Of key note was that the minimum air void content you could achieve was ony around 5%, so we widended the envelope to less than 8% (actualy did the calcs on sphere packing and came up with very similar densities to what could be acheived on site, next step would have been to do a petroraghic analysis and check shape of silt fines). Any clay fines would increase the density which would be achieved. When the material was not confined (i.e. in a mould in the lab) the top 200-300mm always seemed to act loose, so we resorted to excavating the top 150mm and only testing the material below. The MDD between the 2.5kg and 4.5kg was often very similar. The compaction curves were very flat. All plate testing was done using multiple cycles (not just the DIN) method and it took a couple of load cycles to get the material to act elastically. Finally, once the slabs were down we did drilling and TRL DCP probing through them to check the stiffness and performance of the fill. Once it was confined under the slab and roads, the stiffness/CBR was what you would have expected, just very difficult to prove this when the upper surface is unconfined.
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