Study on Mechanical Characteristics of Sidewall of Long-span Working Shaft during Shield Transit

With the continuous development of ultra-long shield tunnels in cities, the safety of long-span working shaft is particularly important. This paper relies on the Wuzhou Road working shaft of Shanghai Beiheng passage project to research the mechanical characteristics of sidewall during the transit stage. By comparing the effects of pilasters on the long-span sidewall, it is concluded that pilasters can effectively share part of the lateral pressure, so as to improve the mechanical performance of the superposition wall. Based on the distribution characteristics of internal force in the shaft wall after setting pilasters and considering the influence of joints in the underground diaphragm wall, the three-dimensional structure model of orthogonal anisotropy is proposed. Compared with the simulated results, the internal force of non-perforated shaft lining, perforated shaft lining and pilasters are analyzed, which can reflect the rule of variation. The research results can provide theoretical support and guidance for the design optimization and construction practice of similar projects in the future.