Good evening everyone... In my opinion (the model on the left in the picture), it seems more logical that the well curtains sit on a raft foundation and the foundation beams sit on these curtains that are equal to the thickness of the continuous foundation beams. In this system, all internal forces can be safely transmitted to the ground. In the other model, there is a step between the foundation beams and some foundation beams around the low beam are placed on the embankment or loose ground. Because the excavation floor level will be partially adjusted according to the lower foundation beams. This situation leads to sudden and different sittings. As a result, the model on the left seems to me more logical and safe as long as the shears to be placed under the foundation beam are at least as rigid as the foundation beams.