Shear force diagram of spring support

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Can someone help to explain the shape of the shear force diagram? Here’s a box culvert model subjected to UDL on top slab. The box drain is supported by pile below , which model as spring, the bottom slab is supported by line spring as well.

Here’s the result of the analysis. I found that in shear force diagram, action is drawn upwards, restraint reaction is drawn downwards. I don’t understand the result. I think it should be like this (blue part), red part is teh original analysis results. Corect me if I am wrong.