Subway tunnel construction vertical shaft foundation pit supporting structure without inner support and construction method

The invention provides a subway tunnel construction vertical shaft foundation pit supporting structure without an inner support and a construction method. The supporting structure comprises fender posts, high-pressure jet grouting piles, concrete enclosing purlins and cushion layers, wherein the high-pressure jet grouting piles, the fender posts and the concrete enclosing purlins are sequentially arranged in the direction from outside to inside of the foundation pit, the high-pressure jet grouting piles and the fender posts are arranged in an engaged mode, the concrete enclosing purlins are horizontally arranged on the vertical face of the foundation pit at certain intervals, and the four edges of the concrete enclosing purlins are connected to the fender posts through embedded steel bars and steel bar connectors correspondingly. According to the subway tunnel vertical shaft foundation pit supporting structure without the inner support and the construction method, on the premise that the construction site is