Referring to the question and answer about Rinter (https://communities.bentley.com/products/geotech-analysis/f/plaxis-soilvision-forum/212033/rinter-value)
We typically do not recommend parameter values as this should be based on data collected from your investigation, laboratory data, engineering experience and judgment.
What kind of investigation or laboratory tests are most commonly carried out to obtain Rinter values?
On a very (very) rough estimation, considering interaction with sand and concrete values of Rinter between 0.8-1.0 can be used, and with clay with concrete values between 0.7-1.0. However, it is very difficult to say exactly what value would best fit your analysis.
Are there any literatures or publications that help us to roughly determine Rinter values?
Direct shear between soil and (let's say) rock surface and compare with the direct shear with soil. But it is very rare to perform these analyses.
One study is given below. Mostly Plaxis recommendations are updated in projects and academical studies.
PDF
but what about the interface between the soil layers?. This R inter generally specifies that interaction between the soil and the structure.
Rinter specifies the strength reduction between both sides of the interface. Whether one side is a structure or both sides are soil or rock doesn't matter. That in practice interfaces are mostly used between structures and soil is true, but that is because we're mostly interested in that interaction and less in the interaction between soil layers not because interfaces cannot handle soil-soil interaction.With kind regards,
Dennis Waterman
So how can we define interaction between the two soil layers by this R inter value? Is there any significant parameter in plaxis 2D dedicated for such kind of simulation?
As I have understood if there is full bonding condition between the two materials then R inter can be taken as 1 and if there is no bonding then 0.01. Is it how it is taking it? What about a partial interaction how this value will help in deciding the same?
How the Rinter value works can be found in the PLAXIS manuals, both the Reference Manual and the Material models manual. So I would suggest you look it up there. If you have partial interaction you would have to know something about for instance the reduced friction angle between the different materials to calculate that back to an Rinter value. There are some guidelines in literature, but values are mostly determined by local building codes.In general, if you have full bonding you could decide to not use an interface at all.
With kind regards,