Xiang Yu led his whole army across the river. Then, according to the Records of the Grand Historian, he “sank all the boats, broke the cooking pots, burned the huts and carried three days’ rations, to show the soldiers that they must die and that not one of them should think of returning.” The idiom 破釜沉舟, to break the pots and sink the boats, means to resolve to fight to the end.
The way back was destroyed on purpose, as an act of command.