how to modeling the geometry?

[kjm]

I want to simulate the grave.
It's form is different inside and outside.



I don't know how to consider both form.
Thickness is over 3m... I wonder how to calculate the gap between the wall(blue question mark area).
Because of geometry, I think solar radiation is not reflected enough.



How to modeling the geometry When the form is different inside and outside?
and is there material database of soil(on the grave)?

[mpazold]

Even if the geometry inside and outside is different and the walls are very thick, we would model it with the outer dimensions. However, there will be an error, e.g. a overestimated heat exchange, because of the overlapping.

For the soil material, i have attached a project with some. However, they are not official, please check the values!