Underground space frame structure and construction method thereof

An underground space frame structure, comprising:

• vertical support piles and multi-layer horizontal components connected to the vertical support piles;
• wherein the vertical support piles are arranged according to designed positions of the vertical support piles to form a column net;
• wherein each of the vertical support piles is a reinforced concrete bored pile;
• each of the vertical support piles comprises a pile body;
• the pile body of each vertical support pile is composed of a reinforcement cage and concrete;
• the pile body of each vertical support pile comprises:
• an upper pile body, a lower pile body, and an expansion section located between the upper pile body and the lower pile body;
• the upper pile body of each pile body is a rectangular body, and the lower pile body of each pile body is a cylindrical body;
• a cross-sectional area of the expansion section is greater than a cross-sectional area of the upper pile body and a cross-sectional area of the lower pile body in each pile body;
• and the upper pile body, the expansion section, and the lower pile body of each pile body are coaxially arranged from top to bottom in that order and formed in one body;
• and
• the multi-layer horizontal components are connected to the vertical support piles by connecting the multi-layer horizontal components to a side of the upper pile body of each vertical support pile layer by layer from top to bottom.