Design and Optimization Method of Internal Support System for Prefabricated Shaft of Underground Subway Station

The research background of this paper is the research on the waist beam of the support system during the shaft construction stage of the subway tunnel construction. Because there is less comprehensive analysis and research at present, a standard design principle is needed to guide the actual construction. Therefore, according to the characteristics of the fabricated shaft and its waist beam, this paper constructs models with different spacing and size in combination with Xi'an Metro Line 8 Project. This paper analyzes the variation characteristics of displacement and stress under different factors, puts forward the design principle of the waist beam, reveals the variation characteristics of the displacement and internal force of the whole system with the depth of the shaft excavation process, and provides an important reference for the theoretical research and engineering design of the prefabricated shaft in the underground subway section. The conclusion shows that the displacement and stress increase gradually with the increase of the distance, reaching 50%, when the distance between the waist beams of the shaft changes between 2-6m, which indicates that the recommended value range of the subway shaft of this size is 4-6m.