go down a blind alley

To pursue something that ultimately does not lead to a fruitful or satisfactory outcome. After spending years trying to prove his hypothesis but failing to get the results he had hoped for, the physicist feared that he gone down a blind alley. Please tell me we haven't gone down a blind alley in our investigation. I'm nervous they're going to cut my funding because my research has gone down a blind alley—every experiment I've tried so far has failed.