Clay/Gravel Mix - PVR Question

[jpw2913]

I have a question regarding a gravel and clay mix and how/if the gravel effects the actual design PVR (potential vertical rise) of the soil profile. Assume that the clay, having some PVR, is actually mixed with gravel in the actual in-situ soil profile. Does the presence of the gravel (or any other non-plastic soil material) have an effect on the actual PVR of the soil profile?
In other words, would a soil profile of 100% clay, having a PI of say 30 have more, less, or the same PVR as a soil profile consisting of 50% of that same clay and 50% gravel?

Thanks for any input.

 

[MTNClimber]

Generally the more non-expansive material mixed in with the expansive clay will result in less overall expansion.

 

[EireChch]

Yes, the less CLAY the less PVR (never heard of that terminology). Specifically, you need to consider The Modified Plasticity Index (I'p) which is defined as the Plasticity Index (Ip) of the soil multiplied by the percentage of particles less than 425µm.