Varying slices

Hello,
I am building a 3D GW model using Feflow. The model has 2 different soil layers. The topography has a slope shape going from 300 m asl (above sea level) to 250 m asl. The first layer is 20 m thick and the second layer is parallel to the topography. When I create my model I have all the slices parallel. However, I want to insert a slice at 270 m asl of constant elevation (horizontal slice). If I do so, I will intercept the top slice and the bottom slice. I need that slice to model a foundation of constant elevation at 270 m asl. Is there a way to do that? Or should I divide my model into tiny slices and model the foundation as cutting through different slices?
Thank you
Sam

Yes, you could use thin layers. Below please find a sketch which schematically illustrates a cross-section. Black lines indicate the input model, blue lines represent “dummy-slices” to model the foundation and the red line is the foundation.

BTW: These dummy-slices are not required anymore with the upcoming FEFLOW 7.0 release. FEFLOW 7.0 will provide the capability to use fully unstructured meshes (e.g. elements of type tetrahedra)

Depending on the spatial discretization you probably need to insert more slices/layers. The sketch roughly shows the framework.