Surcharge of any structure, moving load? Can you explain your question that from where surcharge load comes on retaining wall A?

I would say that it depends on how far the different retaining walls are.

You can compute "manually" the impact of the upstream wall on the downstream using the 2H for 3V rules. If they do not interact each other, then, you just have to consider the retained soils without any surcharge.

I agree with Nathanael, it depends on how far the retaining walls are from each other.

考虑墙体自重，水平地震荷载或震动荷载，