This is nonsense. The tunnel will be far deeper than any possible archaeological remains. Ancient man may have built interesting stone monuments above the ground but he didn't go down very deep, so the tunnel cannot possibly have any effect on the strata that might contain dig sites.
Here's a simple solution: Kill all humanity.
So its people like you that make life difficult for us, we've been wanting to do this for so long. We gotta ease congestion somehow. Not to mention the number of cars on the road is always increasing. 🙄
These schemes are done with a long term view, they don't just decide to start one. There's a very very long process where the project is questioned relentlessly to ensure it is justified.
future archaeologists wonder "what could be signified by their placing these stones immediately over a tunnel?"
we should bite the stone axe-head and return Stonehenge to Wales. there are hundreds of square miles of ancient countryside in Pembrokeshire where it would feel right at home. then there would be no need to dig tunnels etc in Wiltshire.
Whoever planned the original A303 didn't futureproof it at all. It's lead to this current situation where it can't be widened without campaign groups bickering about it.
If the original A303 passed much closer to Salisbury we wouldn't be talking about this problem