all these comments regarding a moat/trench are the solution. when i first get a new location i use the hoe to raise the ground. it is a non-destructible wall. then i build my base inside and start to lower the ground outside to create a moat/trench. this is then at least 2 core beams away from the raised ground. the rock throw troll still can reach farther and it is very annoying, yet it can be easy to fix things when they break it.

one other building concept i start is when in the Black Forest or Swamp i use the Burial Chambers and Crypts as my foundation for a raised base. it is small yet very effective and makes dealing with the risk of death minimal.