come to a dead end
1. Literally, to reach the end of a route where one cannot continue traveling. I knew my GPS was wrong when it told me to turn onto a road that came to a dead end.
2. By extension, to reach a point after which no more progress is possible, as in a project. My research has come to a dead end—every experiment I've tried so far has failed.
come to a dead end
and reach a dead end 1. Lit. to reach a point where one can go no farther and can turn in no new direction. The road comes to a dead end about a mile farther.
2. Fig. to have run out of possible ideas, solutions, energy, etc. I've come to a dead end. I'm fresh out of ideas. The committee reached a dead end on the matter and tabled the whole business.