Clay fill over Rockfill

[atlanticcanada]

We typically require a screening material like 1" to 3" gravel over rockfill (18" minus) to prevent fines from getting down into the rockfill. However, if the contractor does not place this screening zone in the fill, what are the chances of the clay settling? No water will get to the clay fill because it will be underneath the building slab and there are only scattered areas that are bony while other areas have sufficient fines in the rockfill. The clay has been compacted in 8" lifts and has been coming up 100% standard proctor. The pad has about 3 feet of clay fill on it. Thanks for any advice.

 

[GeoPaveTraffic]

I would require a graded zone between the rock fill and the clay. You say no water can there, but what happens if there is a water or sewer pipe leak?