In most cases, piling dirt up WILL kill them. You can maybe put a max of 2" or so of dirt on them.

Could you get away with maybe a single "ditch" for drainage? Just digging a ditch that runs all the water out of the area. You might cut SOME roots, but it would be less invasive to the tree if done properly and far enough from the trunks.

"so how can I ensure that piling dirt around them wont kill them? "

Short answer is you can't. While the effects can vary from tree to tree and how widespread the increased soil elevation is with regards to the root system, any elevation change can have some seriously negative impacts. Even just a couple of inches of soil can smother roots and kill the tree.

cut them down... back fill right over the stumps..

plant new trees.. further from the house

trees or backfill.. one or the other.. no way to deal with both

if they were properly sited ... as to size .. i cant contemplate how some soil settling.. near the house is impacting them .. suggesting.. they are to close to the house ...

but i am guessing w/o pix

i know its not what you want to hear ... sorry

ken