Alternately you can build an earthen wall. You can see how to do it with less stone in yourtube vids. Building walls is quieter and won't attract all mobs from 1/2 mile. If your close to wear Trolls are, they can surprise you while axepicking.

In mean time, until you have things sorted out. If you don't have portals, you can just leave 1 fire and no beds or workbenches. a total of 3 items is needed to trigger a troll raid. These include campfires, benches, and pretty sure a bed and portals count also. I know its extreme if you base is large already. Proper moat/wall should come before base is expanded.

If its beyond hopeless at this point. You can create a new seed and join that one with your current character. Then in the new seed, do not kill elder and you won't have troll raids there.