burn one's bridges behind (you)
    　 　 　破釜沉舟，自斷退路
    例句：
    Now we've burned our bridges behind us and we have no option but to go forward with the project.
    現(xiàn)在我們已經(jīng)破釜沉舟了，除了按計劃前進外，別無選擇。